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Watanabe A, Arqam I, Taylor MJ, Molnar JL. Revisiting Old Questions With New Methods: The Effect of Embryonic Motility on Skull Development in the Domestic Chick. J Morphol 2024; 285:e21785. [PMID: 39434454 DOI: 10.1002/jmor.21785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 09/11/2024] [Accepted: 09/30/2024] [Indexed: 10/23/2024]
Abstract
Muscle loading is known to influence skeletal morphology. Therefore, modification of the biomechanical environment is expected to cause coordinated morphological changes to the bony and cartilaginous tissues. Understanding how this musculoskeletal coordination contributes to morphological variation has relevance to health sciences, developmental biology, and evolutionary biology. To investigate how muscle loading influences skeletal morphology, we replicate a classic in ovo embryology experiment in the domestic chick (Gallus gallus domesticus) while harnessing modern methodologies that allow us to quantify skeletal anatomy more precisely and in situ. We induced rigid muscle paralysis in developing chicks mid-incubation, then compared the morphology of the cranium and mandible between immobilized and untreated embryos using microcomputed tomography and landmark-based geometric morphometric methods. Like earlier studies, we found predictable differences in the size and shape of the cranium and mandible in paralyzed chicks. These differences were concentrated in areas known to experience high strains during feeding, including the jaw joint and jaw muscle attachment sites. These results highlight specific areas of the skull that appear to be mechanosensitive and suggest muscles that could produce the biomechanical stimuli necessary for normal hatchling morphology. Interestingly, these same areas correspond to areas that show the greatest disparity and fastest evolutionary rates across the avian diversity, which suggests that the musculoskeletal integration observed during development extends to macroevolutionary scales. Thus, selection and evolutionary changes to muscle physiology and architecture could generate large and predictable changes to skull morphology. Building upon previous work, the adoption of modern imaging and morphometric techniques allows richer characterization of musculoskeletal integration that empowers researchers to understand how tissue-to-tissue interactions contribute to overall phenotypic variation.
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Affiliation(s)
- Akinobu Watanabe
- New York Institute of Technology, College of Osteopathic Medicine, Old Westbury, New York, USA
- Division of Paleontology, American Museum of Natural History, New York, New York, USA
- Life Sciences Department, Natural History Museum, London, UK
| | - Izza Arqam
- New York Institute of Technology, College of Osteopathic Medicine, Old Westbury, New York, USA
| | - Meredith J Taylor
- New York Institute of Technology, College of Osteopathic Medicine, Old Westbury, New York, USA
| | - Julia L Molnar
- New York Institute of Technology, College of Osteopathic Medicine, Old Westbury, New York, USA
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2
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Tseng ZJ, Terhune CE. Sexual Dimorphism and Divergent Evolutionary Pathways in Primate Cranial Biomechanics: Insights From a Theoretical Morphology Framework. J Morphol 2024; 285:e21780. [PMID: 39385398 DOI: 10.1002/jmor.21780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2024] [Revised: 09/20/2024] [Accepted: 09/25/2024] [Indexed: 10/12/2024]
Abstract
The mammalian order Primates is known for widespread sexual dimorphism in size and phenotype. Despite repeated speculation that primate sexual size dimorphism either facilitates or is in part driven by functional differences in how males and females interact with their environments, few studies have directly assessed the influence of sexual dimorphism on performance traits. Here, we use a theoretical morphology framework to show that sexual dimorphism in primate crania is associated with divergent biomechanical performance traits. The degree of dimorphism is a significant covariate in biomechanical trait divergence between sexes. Males exhibit less efficient but stiffer cranial shapes and significant evolutionary allometry in biomechanical performance, whereas females maintain performance stability across their size spectrum. Evolutionary rates are elevated for efficiency in females whereas males emphasize size-dependent cranial stiffness. These findings support a hypothesis of sex-linked bifurcation in masticatory system performance: larger male crania and faster size evolution partially compensate for low efficiency and reflect a de-emphasis of mechanical leverage, whereas female crania maintain higher mechanical efficiency overall and evolve more rapidly in molar-based masticatory performance. The evolutionary checks-and-balances between size dimorphism and cranial mechanical performance may be a more important driver of primate phenotypic evolution than has been hitherto appreciated.
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Affiliation(s)
- Z Jack Tseng
- Department of Integrative Biology and Museum of Paleontology, University of California, Berkeley, California, USA
| | - Claire E Terhune
- Department of Anthropology, University of Arkansas, Fayetteville, Arkansas, USA
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3
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Forcellati MR, Green TL, Watanabe A. Brain shapes of large-bodied, flightless ratites (Aves: Palaeognathae) emerge through distinct developmental allometries. ROYAL SOCIETY OPEN SCIENCE 2024; 11:240765. [PMID: 39263457 PMCID: PMC11387061 DOI: 10.1098/rsos.240765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 07/27/2024] [Accepted: 07/31/2024] [Indexed: 09/13/2024]
Abstract
Comparative neuroanatomical studies have long debated the role of development in the evolution of novel and disparate brain morphologies. Historically, these studies have emphasized whether evolutionary shifts along conserved or distinct developmental allometric trends cause changes in brain morphologies. However, the degree to which interspecific differences between variably sized taxa originate through modifying developmental allometry remains largely untested. Taxa with disparate brain shapes and sizes thus allow for investigation into how developmental trends contribute to neuroanatomical diversification. Here, we examine a developmental series of large-bodied ratite birds (approx. 60-140 kg). We use three-dimensional geometric morphometrics on cephalic endocasts of common ostriches, emus and southern cassowaries and compare their developmental trajectories with those of the more modestly sized domestic chicken, previously shown to be in the same allometric grade as ratites. The results suggest that ratites and chickens exhibit disparate endocranial shapes not simply accounted for by their size differences. When shape and age are examined, chickens partly exhibit more accelerated and mature brain shapes than ratites of similar size and age. Taken together, our study indicates that disparate brain shapes between these differently sized taxa have emerged from the evolution of distinct developmental allometries, rather than simply following conserved scaling trends.
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Affiliation(s)
- Meghan R Forcellati
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY 10027, USA
- Richard Gilder Graduate School, American Museum of Natural History, New York, NY 10024, USA
| | - Todd L Green
- Biomedical and Anatomical Sciences, New York Institute of Technology, College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR 72401, USA
- Department of Anatomy, New York Institute of Technology, College of Osteopathic Medicine, Old Westbury, NY 11568, USA
| | - Akinobu Watanabe
- Department of Anatomy, New York Institute of Technology, College of Osteopathic Medicine, Old Westbury, NY 11568, USA
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
- Life Sciences Department, Natural History Museum, London SW7 5BD, UK
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4
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Mobbs AED, Boag S. A social science trust taxonomy with emergent vectors and symmetry. Front Psychol 2024; 15:1335020. [PMID: 39282665 PMCID: PMC11392760 DOI: 10.3389/fpsyg.2024.1335020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 08/19/2024] [Indexed: 09/19/2024] Open
Abstract
Introduction Trust is foundational to all social science domains, but to date, there is no unifying theory or consistent measurement basis spanning the social sciences. This research hypothesized that trust forms the basis of an ontology that could unify the social science domains. The proposed ontology comprises a Cartesian plane with axes self-trust and other-trust. Self-trust manifests in dominant behaviors, and other-trust manifests in cooperative behaviors. Both axes are divided into five discrete categories, creating a matrix of 25 cells. All words in the lexicon are allocated into one of these 25 cells. Methods This research started with an existing 14,000-word lexicon of dominance and affiliation. The lexicon was extended by manually identifying and including socially descriptive words with information regarding self-trust, other-trust, dominance, and cooperation. The taxonomy was optimized using the Gradient Descent machine learning algorithm and commercially curated synonyms and antonyms. The t-test was employed as the objective (or loss) function for Gradient Descent optimization. Word vectors were identified using groups of four words related as synonyms and antonyms. Results Over 30,000 words were identified and included in the lexicon. The optimization process yielded a t-score of over 1,000. Over 226,000 vectors were identified, such as malevolent-mean-gentle-benevolent. A new form of symmetry was identified between adjectives and verbs with a common root; for example, the words reject and rejected are horizontally reflected. Discussion The word vectors can create a metrologically compliant basis for psychometric testing. The symmetries provide insight into causes (verbs) and effects (adjectives) in social interactions. These vectors and symmetries offer the social sciences a basis of commonality with natural sciences, enabling unprecedented accuracy and precision in social science measurement.
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Affiliation(s)
- Anthony E D Mobbs
- School of Psychological Sciences, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
| | - Simon Boag
- School of Psychological Sciences, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, Australia
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5
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King L, Zhao Q, Dufeau DL, Kawabe S, Witmer L, Zhou CF, Rayfield EJ, Benton MJ, Watanabe A. Endocranial development in non-avian dinosaurs reveals an ontogenetic brain trajectory distinct from extant archosaurs. Nat Commun 2024; 15:7415. [PMID: 39198439 PMCID: PMC11358377 DOI: 10.1038/s41467-024-51627-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 08/13/2024] [Indexed: 09/01/2024] Open
Abstract
Modern birds possess highly encephalized brains that evolved from non-avian dinosaurs. Evolutionary shifts in developmental timing, namely juvenilization of adult phenotypes, have been proposed as a driver of head evolution along the dinosaur-bird transition, including brain morphology. Testing this hypothesis requires a sufficient developmental sampling of brain morphology in non-avian dinosaurs. In this study, we harness brain endocasts of a postnatal growth series of the ornithischian dinosaur Psittacosaurus and several other immature and mature non-avian dinosaurs to investigate how evolutionary changes to brain development are implicated in the origin of the avian brain. Using three-dimensional characterization of neuroanatomical shape across archosaurian reptiles, we demonstrate that (i) the brain of non-avian dinosaurs underwent a distinct developmental trajectory compared to alligators and crown birds; (ii) ornithischian and non-avialan theropod dinosaurs shared a similar developmental trajectory, suggesting that their derived trajectory evolved in their common ancestor; and (iii) the evolutionary shift in developmental trajectories is partly consistent with paedomorphosis underlying overall brain shape evolution along the dinosaur-bird transition; however, the heterochronic signal is not uniform across time and neuroanatomical region suggesting a highly mosaic acquisition of the avian brain form.
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Affiliation(s)
- Logan King
- Institute of Vertebrate Paleontology & Paleoanthropology, Chinese Academy of Sciences, Beijing, China.
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, UK.
| | - Qi Zhao
- Institute of Vertebrate Paleontology & Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| | - David L Dufeau
- Department of Anatomy and Pathology, Marian University College of Osteopathic Medicine, Indianapolis, IN, USA
| | - Soichiro Kawabe
- Institute of Dinosaur Research, Fukui Prefectural University, Eiheiji, Fukui, Japan
- Fukui Prefectural Dinosaur Museum, Katsuyama, Fukui, Japan
| | - Lawrence Witmer
- Department of Biomedical Sciences, Ohio University Heritage College of Osteopathic Medicine, Athens, OH, USA
- Ohio Center for Ecology and Evolutionary Studies, Ohio University, Athens, OH, USA
| | - Chang-Fu Zhou
- College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, Shandong, China
| | - Emily J Rayfield
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, UK
| | - Michael J Benton
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, UK
| | - Akinobu Watanabe
- Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA.
- Division of Paleontology, American Museum of Natural History, New York, NY, USA.
- Life Sciences Department, Natural History Museum, London, UK.
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6
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Merchant HN, Portugal SJ, Bennett NC, Janse van Vuuren AK, Faulkes CG, Bowen J, Hart DW. New insights into morphological adaptation in common mole-rats ( Cryptomys hottentotus hottentotus) along an aridity gradient. Ecol Evol 2024; 14:e11301. [PMID: 38651162 PMCID: PMC11033624 DOI: 10.1002/ece3.11301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 03/28/2024] [Accepted: 04/05/2024] [Indexed: 04/25/2024] Open
Abstract
Morphological adaptation is the change in the form of an organism that benefits the individual in its current habitat. Mole-rats (family Bathyergidae), despite being subterranean, are impacted by both local and broad-scale environmental conditions that occur above ground. Common mole-rats (Cryptomys hottentotus hottentotus) present an ideal mammalian model system for the study of morphological variation in response to ecology, as this species is found along an aridity gradient and thus can be sampled from geographically non-overlapping populations of the same species along an environmental longitudinal cline. Using the mass of five internal organs, ten skeletal measurements and 3D morphometric analyses of skulls, we assessed the morphology of wild non-breeding individuals from five common mole-rat populations in South Africa. We found that the body mass and mean relative mass of the spleen and kidneys in arid populations was larger, and individuals from arid regions possessed shorter legs and larger inter-shoulder widths compared to individuals from mesic regions. Additionally, arid populations demonstrated greater skull depth, and shape change of features such as angular processes of the lower jaw than mesic individuals, indicating that these distinct geographic populations show differences corresponding to the aridity gradient, potentially in response to environmental factors such as the variation in food sources found between different habitats, in addition to different soil compositions found in the different regions. Arid populations potentially require a stronger jaw and neck musculature associated with mastication to chew xeric-adapted plants and to dig through hard soil types, whereas mesic populations excavate through soft, looser soil and may make use of their front limbs to aid the movement of soils when digging. Aridity influences the morphology of this species and could indicate the impact of environmental changes on speciation and mammalian skull morphology.
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Affiliation(s)
- Hana N. Merchant
- Department of Biological Sciences, School of Life and Environmental SciencesRoyal Holloway University of LondonEgham, SurreyUK
- School of Biological and Behavioural SciencesQueen Mary University of LondonLondonUK
| | - Steven J. Portugal
- Department of Biological Sciences, School of Life and Environmental SciencesRoyal Holloway University of LondonEgham, SurreyUK
| | - Nigel C. Bennett
- Department of Zoology and EntomologyUniversity of PretoriaPretoriaGautengSouth Africa
| | | | - Chris G. Faulkes
- School of Biological and Behavioural SciencesQueen Mary University of LondonLondonUK
| | - James Bowen
- Faculty of Science, Technology, Engineering, and MathematicsOpen UniversityMilton KeynesUK
| | - Daniel W. Hart
- Department of Zoology and EntomologyUniversity of PretoriaPretoriaGautengSouth Africa
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7
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Pandelis GG, Grundler MC, Rabosky DL. Ecological correlates of cranial evolution in the megaradiation of dipsadine snakes. BMC Ecol Evol 2023; 23:48. [PMID: 37679675 PMCID: PMC10485986 DOI: 10.1186/s12862-023-02157-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 08/22/2023] [Indexed: 09/09/2023] Open
Abstract
BACKGROUND Dipsadine snakes represent one of the most spectacular vertebrate radiations that have occurred in any continental setting, with over 800 species in South and Central America. Their species richness is paralleled by stunning ecological diversity, ranging from arboreal snail-eating and aquatic eel-eating specialists to terrestrial generalists. Despite the ecological importance of this clade, little is known about the extent to which ecological specialization shapes broader patterns of phenotypic diversity within the group. Here, we test how habitat use and diet have influenced morphological diversification in skull shape across 160 dipsadine species using micro-CT and 3-D geometric morphometrics, and we use a phylogenetic comparative approach to test the contributions of habitat use and diet composition to variation in skull shape among species. RESULTS We demonstrate that while both habitat use and diet are significant predictors of shape in many regions of the skull, habitat use significantly predicts shape in a greater number of skull regions when compared to diet. We also find that across ecological groupings, fossorial and aquatic behaviors result in the strongest deviations in morphospace for several skull regions. We use simulations to address the robustness of our results and describe statistical anomalies that can arise from the application of phylogenetic generalized least squares to complex shape data. CONCLUSIONS Both habitat and dietary ecology are significantly correlated with skull shape in dipsadines; the strongest relationships involved skull shape in snakes with aquatic and fossorial lifestyles. This association between skull morphology and multiple ecological axes is consistent with a classic model of adaptive radiation and suggests that ecological factors were an important component in driving morphological diversification in the dipsadine megaradiation.
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Affiliation(s)
- Gregory G Pandelis
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, 48109, USA.
- Museum of Zoology, University of Michigan, Ann Arbor, Michigan, 48109, USA.
- Amphibian and Reptile Diversity Research Center, Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019, USA.
| | - Michael C Grundler
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, 48109, USA
- Museum of Zoology, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | - Daniel L Rabosky
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, Michigan, 48109, USA
- Museum of Zoology, University of Michigan, Ann Arbor, Michigan, 48109, USA
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8
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Watanabe A, Marshall SS, Gignac PM. Dumbbell-shaped brains of Polish crested chickens as a model system for the evolution of novel brain morphologies. J Anat 2023; 243:421-430. [PMID: 37165612 PMCID: PMC10439378 DOI: 10.1111/joa.13883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 03/28/2023] [Accepted: 04/27/2023] [Indexed: 05/12/2023] Open
Abstract
The evolutionary history of vertebrates is replete with emergence of novel brain morphologies, including the origin of the human brain. Existing model organisms and toolkits for investigating drivers of neuroanatomical innovations have largely proceeded on mammals. As such, a compelling non-mammalian model system would facilitate our understanding of how unique brain morphologies evolve across vertebrates. Here, we present the domestic chicken breed, white crested Polish chickens, as an avian model for investigating how novel brain morphologies originate. Most notably, these crested chickens exhibit cerebral herniation from anterodorsal displacement of the telencephalon, which results in a prominent protuberance on the dorsal aspect of the skull. We use a high-density geometric morphometric approach on cephalic endocasts to characterize their brain morphology. Compared with standard white Leghorn chickens (WLCs) and modern avian diversity, the results demonstrate that crested chickens possess a highly variable and unique overall brain configuration. Proportional sizes of neuroanatomical regions are within the observed range of extant birds sampled in this study, but Polish chickens differ from WLCs in possessing a relatively larger cerebrum and smaller cerebellum and medulla. Given their accessibility, phylogenetic proximity, and unique neuroanatomy, we propose that crested breeds, combined with standard chickens, form a promising comparative system for investigating the emergence of novel brain morphologies.
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Affiliation(s)
- Akinobu Watanabe
- Department of AnatomyNew York Institute of Technology College of Osteopathic MedicineOld WestburyNew YorkUSA
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNew YorkUSA
- Department of Life SciencesNatural History MuseumLondonUK
| | - Sylvia S. Marshall
- Department of AnatomyNew York Institute of Technology College of Osteopathic MedicineOld WestburyNew YorkUSA
| | - Paul M. Gignac
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNew YorkUSA
- Department of Cellular and Molecular MedicineUniversity of Arizona College of MedicineTucsonArizonaUSA
- MicroCT Imaging Consortium for Research and OutreachUniversity of ArkansasFayettevilleArkansasUSA
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9
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Tharakan S, Shepherd N, Gower DJ, Stanley EL, Felice RN, Goswami A, Watanabe A. High-Density Geometric Morphometric Analysis of Intraspecific Cranial Integration in the Barred Grass Snake ( Natrix helvetica) and Green Anole ( Anolis carolinensis). Integr Org Biol 2023; 5:obad022. [PMID: 37397233 PMCID: PMC10311474 DOI: 10.1093/iob/obad022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 04/30/2023] [Accepted: 06/02/2023] [Indexed: 07/04/2023] Open
Abstract
How do phenotypic associations intrinsic to an organism, such as developmental and mechanical processes, direct morphological evolution? Comparisons of intraspecific and clade-wide patterns of phenotypic covariation could inform how population-level trends ultimately dictate macroevolutionary changes. However, most studies have focused on analyzing integration and modularity either at macroevolutionary or intraspecific levels, without a shared analytical framework unifying these temporal scales. In this study, we investigate the intraspecific patterns of cranial integration in two squamate species: Natrix helvetica and Anolis carolinensis. We analyze their cranial integration patterns using the same high-density three-dimensional geometric morphometric approach used in a prior squamate-wide evolutionary study. Our results indicate that Natrix and Anolis exhibit shared intraspecific cranial integration patterns, with some differences, including a more integrated rostrum in the latter. Notably, these differences in intraspecific patterns correspond to their respective interspecific patterns in snakes and lizards, with few exceptions. These results suggest that interspecific patterns of cranial integration reflect intraspecific patterns. Hence, our study suggests that the phenotypic associations that direct morphological variation within species extend across micro- and macroevolutionary levels, bridging these two scales.
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Affiliation(s)
- S Tharakan
- Department of Anatomy, New York Institute of Technology, College of Osteopathic Medicine, 100 Northern Boulevard, Old Westbury, NY 11568, USA
| | - N Shepherd
- Department of Genetics, Evolution, and Environment, University College London, Gower Street, London, WC1E 6BT, UK
| | - D J Gower
- Life Sciences Division, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - E L Stanley
- Digital Imaging Division, Florida Museum of Natural History, University of Florida, Gainesville, FL 32611-0001, USA
| | - R N Felice
- Department of Genetics, Evolution, and Environment, University College London, Gower Street, London, WC1E 6BT, UK
- Life Sciences Division, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
- Centre for Integrative Anatomy, Department of Cell and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - A Goswami
- Department of Genetics, Evolution, and Environment, University College London, Gower Street, London, WC1E 6BT, UK
- Life Sciences Division, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
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10
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White HE, Tucker AS, Fernandez V, Portela Miguez R, Hautier L, Herrel A, Urban DJ, Sears KE, Goswami A. Pedomorphosis in the ancestry of marsupial mammals. Curr Biol 2023:S0960-9822(23)00457-8. [PMID: 37119816 DOI: 10.1016/j.cub.2023.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 02/27/2023] [Accepted: 04/05/2023] [Indexed: 05/01/2023]
Abstract
Within mammals, different reproductive strategies (e.g., egg laying, live birth of extremely underdeveloped young, and live birth of well-developed young) have been linked to divergent evolutionary histories. How and when developmental variation across mammals arose is unclear. While egg laying is unquestionably considered the ancestral state for all mammals, many long-standing biases treat the extreme underdeveloped state of marsupial young as the ancestral state for therian mammals (clade including both marsupials and placentals), with the well-developed young of placentals often considered the derived mode of development. Here, we quantify mammalian cranial morphological development and estimate ancestral patterns of cranial shape development using geometric morphometric analysis of the largest comparative ontogenetic dataset of mammals to date (165 specimens, 22 species). We identify a conserved region of cranial morphospace for fetal specimens, after which cranial morphology diversified through ontogeny in a cone-shaped pattern. This cone-shaped pattern of development distinctively reflected the upper half of the developmental hourglass model. Moreover, cranial morphological variation was found to be significantly associated with the level of development (position on the altricial-precocial spectrum) exhibited at birth. Estimation of ancestral state allometry (size-related shape change) reconstructs marsupials as pedomorphic relative to the ancestral therian mammal. In contrast, the estimated allometries for the ancestral placental and ancestral therian were indistinguishable. Thus, from our results, we hypothesize that placental mammal cranial development most closely reflects that of the ancestral therian mammal, while marsupial cranial development represents a more derived mode of mammalian development, in stark contrast to many interpretations of mammalian evolution.
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Affiliation(s)
- Heather E White
- Science Department, Natural History Museum, Cromwell Road, London SW7 5BD, UK; Centre for Craniofacial and Regenerative Biology, King's College London, Great Maze Pond, London SE1 9RT, UK; Division of Biosciences, University College London, Gower Street, London WC1E 6DE, UK.
| | - Abigail S Tucker
- Centre for Craniofacial and Regenerative Biology, King's College London, Great Maze Pond, London SE1 9RT, UK
| | - Vincent Fernandez
- European Synchrotron Radiation Facility, 71 rue des Martyrs, 38000 Grenoble, France
| | | | - Lionel Hautier
- Science Department, Natural History Museum, Cromwell Road, London SW7 5BD, UK; Institut des Sciences de l'Evolution, Université de Montpellier, CNRS, IRD, EPHE, Montpellier 34095, France
| | - Anthony Herrel
- UMR 7179, Centre National de la Recherche Scientifique/Muséum National d'Histoire Naturelle, Département Adaptations du Vivant, 55 rue Buffon, 75005 Paris, France
| | - Daniel J Urban
- Institute of Genomic Biology, University of Illinois, Urbana, IL 61801, USA
| | - Karen E Sears
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Anjali Goswami
- Science Department, Natural History Museum, Cromwell Road, London SW7 5BD, UK; Division of Biosciences, University College London, Gower Street, London WC1E 6DE, UK
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11
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Cordero GA, Birk K, Ruane S, Dinkelacker SA, Janzen FJ. Effects of the egg incubation environment on turtle carapace development. Evol Dev 2023; 25:153-169. [PMID: 36373204 DOI: 10.1111/ede.12425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 08/24/2022] [Accepted: 10/28/2022] [Indexed: 11/16/2022]
Abstract
Developing organisms are often exposed to fluctuating environments that destabilize tissue-scale processes and induce abnormal phenotypes. This might be common in species that lay eggs in the external environment and with little parental care, such as many reptiles. In turtles, morphological development has provided striking examples of abnormal phenotypic patterns, though the influence of the environment remains unclear. To this end, we compared fluctuating asymmetry, as a proxy for developmental instability, in turtle hatchlings incubated in controlled laboratory and unstable natural conditions. Wild and laboratory hatchlings featured similar proportions of supernumerary scales (scutes) on the dorsal shell (carapace). Such abnormal scutes likely elevated shape asymmetry, which was highest in natural nests. Moreover, we tested the hypothesis that hot and dry environments cause abnormal scute formation by subjecting eggs to a range of hydric and thermal laboratory incubation regimes. Shape asymmetry was similar in hatchlings incubated at five constant temperatures (26-30°C). A hot (30°C) and severely Dry substrate yielded smaller hatchlings but scutes were not overtly affected. Our study suggests that changing nest environments contribute to fluctuating asymmetry in egg-laying reptiles, while clarifying the conditions at which turtle shell development remains buffered from the external environment.
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Affiliation(s)
- Gerardo A Cordero
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA.,Department of Animal Biology, Centre for Ecology, Evolution and Environmental Changes, University of Lisbon, Lisbon, Portugal
| | - Katie Birk
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
| | - Sarah Ruane
- Department of Biology, Framingham State University, Framingham, Massachusetts, USA
| | - Stephen A Dinkelacker
- Life Sciences Section, Negaunee Integrative Research Center, Field Museum, Chicago, Illinois, USA
| | - Fredric J Janzen
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
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12
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Vanhaesebroucke O, Larouche O, Cloutier R. Whole-body variational modularity in the zebrafish: an inside-out story of a model species. Biol Lett 2023; 19:20220454. [PMID: 36974665 PMCID: PMC9943880 DOI: 10.1098/rsbl.2022.0454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 02/01/2023] [Indexed: 02/24/2023] Open
Abstract
Actinopterygians are the most diversified clade of extant vertebrates. Their impressive morphological disparity bears witness to tremendous ecological diversity. Modularity, the organization of biological systems into quasi-independent anatomical/morphological units, is thought to increase evolvability of organisms and facilitate morphological diversification. Our study aims to quantify patterns of variational modularity in a model actinopterygian, the zebrafish (Danio rerio), using three-dimensional geometric morphometrics on osteological structures isolated from micro-CT scans. A total of 72 landmarks were digitized along cranial and postcranial ossified regions of 30 adult zebrafishes. Two methods were used to test modularity hypotheses, the covariance ratio and the distance matrix approach. We find strong support for two modules, one comprised paired fins and the other comprised median fins, that are best explained by functional properties of subcarangiform swimming. While the skull is tightly integrated with the rest of the body, its intrinsic integration is relatively weak supporting previous findings that the fish skull is a modular structure. Our results provide additional support for the recognition of similar hypotheses of modularity identified based on external morphology in various teleosts, and at least two variational modules are proposed. Thus, our results hint at the possibility that internal and external modularity patterns may be congruent.
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Affiliation(s)
- Olivia Vanhaesebroucke
- Laboratoire de Paléontologie et Biologie évolutive, Département de biologie, chimie et géographie, Université du Québec à Rimouski, Rimouski, Québec, Canada G5L 3A1
| | - Olivier Larouche
- Laboratoire de Paléontologie et Biologie évolutive, Département de biologie, chimie et géographie, Université du Québec à Rimouski, Rimouski, Québec, Canada G5L 3A1
- Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA
| | - Richard Cloutier
- Laboratoire de Paléontologie et Biologie évolutive, Département de biologie, chimie et géographie, Université du Québec à Rimouski, Rimouski, Québec, Canada G5L 3A1
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13
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Decoupled Patterns of Diversity and Disparity Characterize an Ecologically Specialized Lineage of Neotropical Cricetids. Evol Biol 2023. [DOI: 10.1007/s11692-022-09596-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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14
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Vargas‐Parra EE, Hopkins MJ. Modularity in the trilobite head consistent with the hypothesized segmental origin of the eyes. Evol Dev 2022; 24:177-188. [PMID: 36111749 PMCID: PMC9786538 DOI: 10.1111/ede.12418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 07/06/2022] [Accepted: 08/18/2022] [Indexed: 12/30/2022]
Abstract
The trilobite head served multiple functions and was composed of several fused segments. Yet, the underlying organization of the trilobite head, and whether patterns are conserved across trilobites, remains unclear. Modeling the head as being composed of modules, or subunits that vary and thus have the potential to evolve semi-independently can reveal underlying patterns of organization. Hypotheses of modular organization based on the comparative developmental biology of arthropods were evaluated using geometric morphometrics. Two-dimensional (semi)landmark datasets collected from the cranidia of two Ordovician trilobite species, Calyptaulax annulata (Phacopida) and Cloacaspis senilis (Olenida sensu Adrain, 2011) were analyzed. The degree and pattern of modularity were assessed using the covariance ratio (CR), which compares the covariation within putative modules to the covariation between them, and the fit of different models was compared using an effect size measure derived from the CR. When treating the eyes as a distinct module, the best modular hypothesis identified for C. annulata shows the eyes and anteriormost region of the head integrated as a single module. The best modular hypotheses for C. senilis are more complex but the eyes still covary mostly strongly with the anterior part of the head. The latter is also the case for all other well-supported models for both species. These results can be interpreted as a developmental signal corresponding to the anteriormost ocular segment of early arthropods that is retained throughout development, despite any likely selective pressures related to functional needs.
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Affiliation(s)
| | - Melanie J. Hopkins
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNew YorkUSA
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15
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Russo LF, Meloro C, De Silvestri M, Chadwick EA, Loy A. Better sturdy or slender? Eurasian otter skull plasticity in response to feeding ecology. PLoS One 2022; 17:e0274893. [PMID: 36174011 PMCID: PMC9521905 DOI: 10.1371/journal.pone.0274893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 09/06/2022] [Indexed: 11/18/2022] Open
Abstract
Otters are semi-aquatic mammals specialized in feeding on aquatic prey. The Eurasian otter Lutra lutra is the most widely distributed otter species. Despite a low degree of genetic variation across its European range, the population from Great Britain exhibits distinct genetic structuring. We examined 43 skulls of adult Eurasian otters belonging to 18 sampling localities and three genetic clusters (Shetlands, Wales and Scotland). For each sample location, information regarding climate was described using bioclimatic variables from WorldClim, and information on otter diet was extracted from the literature. By using photogrammetry, 3D models were obtained for each skull. To explore any evidence of adaptive divergence within these areas we used a three dimensional geometric morphometric approach to test differences in skull size and shape between areas with genetically distinct populations, as well as the influence of diet, isolation by distance and climate. Males were significantly larger in skull size than females across all the three genetic clusters. Skull shape, but not size, appeared to differ significantly among genetic clusters, with otters from Shetland exhibiting wider zygomatic arches and longer snouts compared to otters from Wales, whereas otters from Scotland displayed intermediate traits. A significant relationship could also be found between skull shape variation, diet as well as climate. Specifically, otters feeding on freshwater fish had more slender and short-snouted skulls compared to otters feeding mostly on marine fish. Individuals living along the coast are characterised by a mixed feeding regime based on marine fish and crustaceans and their skull showed an intermediate shape. Coastal and island otters also had larger orbits and eyes more oriented toward the ground, a larger nasal cavity, and a larger distance between postorbital processes and zygomatic arch. These functional traits could also represent an adaptation to favour the duration and depth of diving, while the slender skull of freshwater feeding otters could improve the hydrodynamics.
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Affiliation(s)
- Luca Francesco Russo
- EnvixLab, Department of Biosciences and Territory, Università degli Studi del Molise, Pesche, Italy
| | - Carlo Meloro
- Research Centre in Evolutionary Anthropology and Palaeoecology, Liverpool John Moores University, Liverpool, United Kingdom
- * E-mail:
| | - Mara De Silvestri
- EnvixLab, Department of Biosciences and Territory, Università degli Studi del Molise, Pesche, Italy
| | - Elizabeth A. Chadwick
- Cardiff University, Biomedical Science Building, Museum Avenue, Cardiff, United Kingdom
| | - Anna Loy
- EnvixLab, Department of Biosciences and Territory, Università degli Studi del Molise, Pesche, Italy
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16
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Miranda FR, Garbino GST, Machado FA, Perini FA, Santos FR, Casali DM. Taxonomic revision of maned sloths, subgenus Bradypus ( Scaeopus), Pilosa, Bradypodidae, with revalidation of Bradypus crinitus Gray, 1850. J Mammal 2022. [DOI: 10.1093/jmammal/gyac059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
We present a taxonomic revision of maned sloths, subgenus Bradypus (Scaeopus), a taxon endemic to the Brazilian Atlantic Forest and currently composed of a single species, the vulnerable Bradypus torquatus. Our review is based on coalescent species delimitation analyses using mitochondrial and nuclear DNA, morphological analyses, and field observations. Our integrative approach demonstrates that two species of maned sloth can be recognized: the northern maned sloth (Bradypus torquatusIlliger, 1811) occurring in the Brazilian states of Bahia and Sergipe, and the southern maned sloth (Bradypus crinitusGray, 1850), occurring in Rio de Janeiro and Espirito Santo states. The two species diverged in the Early Pliocene and are allopatrically distributed. We discuss the biogeographic pattern of the two maned sloth species, comparing it with other Atlantic Forest mammals. We also suggest that the conservation status of both maned sloths needs to be reassessed after this taxonomic rearrangement.
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Affiliation(s)
- Flavia R Miranda
- Universidade Estadual de Santa Cruz, Campus Soane Nazaré de Andrade , Rod. Jorge Amado, Km 16 - Salobrinho, 45662-900 Ilhéus, Bahia, 64200-240 , Brazil
- Instituto de Pesquisa e Conservação de Tamanduás no Brasil , Rua do Comercio, s/n, Sala 130 Conjunto Porto das Barcas, Parnaíba, Piauí, 64200-240 , Brazil
| | - Guilherme S T Garbino
- Universidade Federal de Viçosa (UFV), Museu de Zoologia João Moojen, Departamento de Biologia Animal , Avenida Peter Henry Rolfs, s/n, Campus Universitário, 36570-900 Viçosa, Minas Gerais , Brazil
| | - Fabio A Machado
- Department of Biological Sciences, Virginia Tech , 926 West Campus Drive, Blacksburg, Virginia 24061 , USA
| | - Fernando A Perini
- Universidade Federal de Minas Gerais, Laboratório de Evolução de Mamíferos , Av. Antônio Carlos, 6627, 31270-901 Belo Horizonte, Minas Gerais , Brazil
| | - Fabricio R Santos
- Universidade Federal de Minas Gerais, Laboratório de Biodiversidade e Evolução Molecular , Av. Antônio Carlos, 6627, 31270-901 Belo Horizonte, Minas Gerais , Brazil
| | - Daniel M Casali
- Universidade Federal de Minas Gerais, Laboratório de Evolução de Mamíferos , Av. Antônio Carlos, 6627, 31270-901 Belo Horizonte, Minas Gerais , Brazil
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17
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The tempo of cetacean cranial evolution. Curr Biol 2022; 32:2233-2247.e4. [DOI: 10.1016/j.cub.2022.04.060] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/28/2022] [Accepted: 04/21/2022] [Indexed: 01/05/2023]
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18
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Pilatti P, Moratelli R, Aguiar LMS, Astúa D. Distribution and Morphological Variation of Xeronycteris vieirai Gregorin and Ditchfield, 2005 (Chiroptera, Phyllostomidae). ACTA CHIROPTEROLOGICA 2022. [DOI: 10.3161/15081109acc2021.23.2.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Patricia Pilatti
- Laboratório de Mastozoologia, Departamento de Zoologia, Universidade Federal de Pernambuco. Avenida Professor Moraes Rêgo, s/n, Cidade Universitária, Recife, PE, 50670-901, Brazil
| | - Ricardo Moratelli
- Fiocruz Mata Atlântica, Fundação Oswaldo Cruz. Rua Sampaio Corrêa s/n, Colônia Juliano Moreira, Taquara, Rio de Janeiro, RJ, 22713-375, Brazil
| | - Ludmilla M. S. Aguiar
- Laboratório de Biologia e Conservação de Morcegos, Departamento de Zoologia, Instituto de Biologia, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Asa Norte, Brasília, DF, 70910-900, Brazil
| | - Diego Astúa
- Laboratório de Mastozoologia, Departamento de Zoologia, Universidade Federal de Pernambuco. Avenida Professor Moraes Rêgo, s/n, Cidade Universitária, Recife, PE, 50670-901, Brazil
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19
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Hou M, Fagan MJ. Assessments of bilateral asymmetry with application in human skull analysis. PLoS One 2021; 16:e0258146. [PMID: 34614014 PMCID: PMC8494363 DOI: 10.1371/journal.pone.0258146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 09/21/2021] [Indexed: 11/19/2022] Open
Abstract
As a common feature, bilateral symmetry of biological forms is ubiquitous, but in fact rarely exact. In a setting of analytic geometry, bilateral symmetry is defined with respect to a point, line or plane, and the well-known notions of fluctuating asymmetry, directional asymmetry and antisymmetry are recast. A meticulous scheme for asymmetry assessments is proposed and explicit solutions to them are derived. An investigation into observational errors of points representing the geometric structure of an object offers a baseline reference for asymmetry assessment of the object. The proposed assessments are applicable to individual, part or all point pairs at both individual and collective levels. The exact relationship between the developed treatments and the widely used Procrustes method in asymmetry assessment is examined. An application of the proposed assessments to a large collection of human skull data in the form of 3D landmark coordinates finds: (a) asymmetry of most skulls is not fluctuating, but directional if measured about a plane fitted to shared landmarks or side landmarks for balancing; (b) asymmetry becomes completely fluctuating if one side of a skull could be slightly rotated and translated with respect to the other side; (c) female skulls are more asymmetric than male skulls. The methodology developed in this study is rigorous and transparent, and lays an analytical base for investigation of structural symmetries and asymmetries in a wide range of biological and medical applications.
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Affiliation(s)
- M. Hou
- Department of Engineering, Medical and Biological Engineering, Faculty of Science & Engineering, University of Hull, Hull, United Kingdom
| | - M. J. Fagan
- Department of Engineering, Medical and Biological Engineering, Faculty of Science & Engineering, University of Hull, Hull, United Kingdom
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20
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Taverne M, Dutel H, Fagan M, Štambuk A, Lisičić D, Tadić Z, Fabre AC, Herrel A. From micro to macroevolution: drivers of shape variation in an island radiation of Podarcis lizards. Evolution 2021; 75:2685-2707. [PMID: 34382693 DOI: 10.1111/evo.14326] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 07/16/2021] [Accepted: 07/21/2021] [Indexed: 11/30/2022]
Abstract
Phenotypictraits have been shown to evolve in response to variation in the environment. However, the evolutionary processes underlying the emergence of phenotypic diversity can typically only be understood at the population level. Consequently, how subtle phenotypic differences at the intraspecific level can give rise to larger-scale changes in performance and ecology remains poorly understood. We here tested for the covariation between ecology, bite force, jaw muscle architecture, and the three-dimensional shape of the cranium and mandible in 16 insular populations of the lizards Podarcis melisellensis and P. sicula. We then compared the patterns observed at the among-population level with those observed at the interspecific level. We found that three-dimensional head shape as well as jaw musculature evolve similarly under similar ecological circumstances. Depending on the type of food consumed or on the level of sexual competition, different muscle groups were more developed and appeared to underlie changes in cranium and mandible shape. Our findings show that the local selective regimes are primary drivers of phenotypic variation resulting in predictable patterns of form and function. Moreover, intraspecific patterns of variation were generally consistent with those at the interspecific level, suggesting that microevolutionary variation may translate into macroevolutionary patterns of ecomorphological diversity.
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Affiliation(s)
- Maxime Taverne
- UMR 7179, Département Adaptations du Vivant, Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, Paris, France
| | - Hugo Dutel
- School of Earth Sciences, University of Bristol, Bristol, UK.,Department of Engineering, Medical and Biological Engineering Research Group, University of Hull, Hull, UK
| | - Michael Fagan
- Department of Engineering, Medical and Biological Engineering Research Group, University of Hull, Hull, UK
| | - Anamaria Štambuk
- Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Duje Lisičić
- Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Zoran Tadić
- Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | | | - Anthony Herrel
- UMR 7179, Département Adaptations du Vivant, Muséum National d'Histoire Naturelle, Centre National de la Recherche Scientifique, Paris, France
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21
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Moraes ABDE, DE Moraes DCS, Alencar CERD, Freire FAM. Native and non-native species of Litopenaeus Pérez-Farfante, 1969 (Crustacea: Penaeidae) from the East Atlantic: Geometric morphometrics as a tool for taxonomic discrimination. AN ACAD BRAS CIENC 2021; 93:e20200107. [PMID: 34231756 DOI: 10.1590/0001-3765202120200107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 10/25/2020] [Indexed: 11/21/2022] Open
Abstract
The shape of the secondary sexual characters is, traditionally, used to discriminate the marine shrimps at the species level. However, the qualitative evaluation of structures that are morphologically variable in the taxonomy of species can favor misunderstandings and misidentifications. These possibilities of taxonomic inaccuracies are especially alarming when there is a need to evaluate the invasion of introduced species. The present study used geometric morphometric analyses to identify differences in the cephalothorax shape that would help discriminate the native and non-native species of Litopenaeus of the South American coast. The comparative morphology analysis was conducted using the right profile of adult males' cephalothorax of L. schmitti, captured in the natural environment, and L. vannamei captured in the natural environment or grown in shrimp farms. In intraspecific evaluation, it was not possible to distinguish the specimens of L. vannamei that were grown in shrimp farms from those acclimated to the natural environment. However, significant interspecific differences in shape were found in the shape of this body structure. Additionally, the base position of the first rostral spine to the tip of the hepatic spine is indicated as a characteristic that can be used to distinguish these two species by eye in the field.
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Affiliation(s)
- Alex B DE Moraes
- Universidade Federal do Rio Grande do Norte, Departamento de Botânica e Zoologia, Laboratório de Biologia, Ecologia e Evolução de Crustáceos (LABEEC), Campus Universitário Lagoa Nova, Caixa Postal 1524, 59072-970 Natal, RN, Brazil
| | - Daniele C S DE Moraes
- Universidade Federal do Rio Grande do Norte, Departamento de Botânica e Zoologia, Laboratório de Biologia, Ecologia e Evolução de Crustáceos (LABEEC), Campus Universitário Lagoa Nova, Caixa Postal 1524, 59072-970 Natal, RN, Brazil
| | - Carlos Eduardo R D Alencar
- Universidade Federal do Rio Grande do Norte, Departamento de Botânica e Zoologia, Laboratório de Biologia, Ecologia e Evolução de Crustáceos (LABEEC), Campus Universitário Lagoa Nova, Caixa Postal 1524, 59072-970 Natal, RN, Brazil.,Universidade Regional do Cariri, Departamento de Ciências Biológicas, Laboratório de Crustáceos do Semiárido (LACRUSE), Rua Cel. Antônio Luiz, 1161, 63105-000 Crato, CE, Brazil
| | - Fúlvio A M Freire
- Universidade Federal do Rio Grande do Norte, Departamento de Botânica e Zoologia, Laboratório de Biologia, Ecologia e Evolução de Crustáceos (LABEEC), Campus Universitário Lagoa Nova, Caixa Postal 1524, 59072-970 Natal, RN, Brazil
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22
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Watanabe A, Balanoff AM, Gignac PM, Gold MEL, Norell MA. Novel neuroanatomical integration and scaling define avian brain shape evolution and development. eLife 2021; 10:68809. [PMID: 34227464 PMCID: PMC8260227 DOI: 10.7554/elife.68809] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 06/15/2021] [Indexed: 12/17/2022] Open
Abstract
How do large and unique brains evolve? Historically, comparative neuroanatomical studies have attributed the evolutionary genesis of highly encephalized brains to deviations along, as well as from, conserved scaling relationships among brain regions. However, the relative contributions of these concerted (integrated) and mosaic (modular) processes as drivers of brain evolution remain unclear, especially in non-mammalian groups. While proportional brain sizes have been the predominant metric used to characterize brain morphology to date, we perform a high-density geometric morphometric analysis on the encephalized brains of crown birds (Neornithes or Aves) compared to their stem taxa—the non-avialan coelurosaurian dinosaurs and Archaeopteryx. When analyzed together with developmental neuroanatomical data of model archosaurs (Gallus, Alligator), crown birds exhibit a distinct allometric relationship that dictates their brain evolution and development. Furthermore, analyses by neuroanatomical regions reveal that the acquisition of this derived shape-to-size scaling relationship occurred in a mosaic pattern, where the avian-grade optic lobe and cerebellum evolved first among non-avialan dinosaurs, followed by major changes to the evolutionary and developmental dynamics of cerebrum shape after the origin of Avialae. Notably, the brain of crown birds is a more integrated structure than non-avialan archosaurs, implying that diversification of brain morphologies within Neornithes proceeded in a more coordinated manner, perhaps due to spatial constraints and abbreviated growth period. Collectively, these patterns demonstrate a plurality in evolutionary processes that generate encephalized brains in archosaurs and across vertebrates.
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Affiliation(s)
- Akinobu Watanabe
- Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, United States.,Division of Paleontology, American Museum of Natural History, New York, United States.,Department of Life Sciences Vertebrates Division, Natural History Museum, London, United Kingdom
| | - Amy M Balanoff
- Division of Paleontology, American Museum of Natural History, New York, United States.,Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, United States
| | - Paul M Gignac
- Division of Paleontology, American Museum of Natural History, New York, United States.,Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, United States
| | - M Eugenia L Gold
- Division of Paleontology, American Museum of Natural History, New York, United States.,Biology Department, Suffolk University, Boston, United States
| | - Mark A Norell
- Division of Paleontology, American Museum of Natural History, New York, United States
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23
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Wilson JD, Zapata LV, Barone ML, Cotoras DD, Poy D, Ramírez MJ. Geometric morphometrics reveal sister species in sympatry and a cline in genital morphology in a ghost spider genus. ZOOL SCR 2021. [DOI: 10.1111/zsc.12478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jeremy D. Wilson
- Museo Argentino de Ciencias Naturales Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires Argentina
| | - Lorena V. Zapata
- Museo Argentino de Ciencias Naturales Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires Argentina
| | - Mariana L. Barone
- Museo Argentino de Ciencias Naturales Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires Argentina
| | - Darko D. Cotoras
- Department of Entomology California Academy of Sciences San Francisco California
| | - Dante Poy
- Museo Argentino de Ciencias Naturales Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires Argentina
| | - Martín J. Ramírez
- Museo Argentino de Ciencias Naturales Consejo Nacional de Investigaciones Científicas y Técnicas Buenos Aires Argentina
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24
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Scarsbrook L, Sherratt E, Hitchmough RA, Rawlence NJ. Skeletal variation in extant species enables systematic identification of New Zealand's large, subfossil diplodactylids. BMC Ecol Evol 2021; 21:67. [PMID: 33906608 PMCID: PMC8080345 DOI: 10.1186/s12862-021-01808-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/23/2021] [Indexed: 11/17/2022] Open
Abstract
New Zealand’s diplodactylid geckos exhibit high species-level diversity, largely independent of discernible osteological changes. Consequently, systematic affinities of isolated skeletal elements (fossils) are primarily determined by comparisons of size, particularly in the identification of Hoplodactylus duvaucelii, New Zealand’s largest extant gecko species. Here, three-dimensional geometric morphometrics of maxillae (a common fossilized element) was used to determine whether consistent shape and size differences exist between genera, and if cryptic extinctions have occurred in subfossil ‘Hoplodactylus cf. duvaucelii’. Sampling included 13 diplodactylid species from five genera, and 11 Holocene subfossil ‘H. cf. duvaucelii’ individuals. We found phylogenetic history was the most important predictor of maxilla morphology among extant diplodactylid genera. Size comparisons could only differentiate Hoplodactylus from other genera, with the remaining genera exhibiting variable degrees of overlap. Six subfossils were positively identified as H. duvaucelii, confirming their proposed Holocene distribution throughout New Zealand. Conversely, five subfossils showed no clear affinities with any modern diplodactylid genera, implying either increased morphological diversity in mainland ‘H. cf. duvaucelii’ or the presence of at least one extinct, large, broad-toed diplodactylid species.
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Affiliation(s)
- Lachie Scarsbrook
- Otago Paleogenetics Laboratory, Department of Zoology, University of Otago, Dunedin, New Zealand.
| | - Emma Sherratt
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | | | - Nicolas J Rawlence
- Otago Paleogenetics Laboratory, Department of Zoology, University of Otago, Dunedin, New Zealand
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25
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Mitchell MJ, Goswami A, Felice RN. Cranial integration in the ring-necked parakeet, Psittacula krameri (Psittaciformes: Psittaculidae). Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
The study of integration and modularity aims to describe the organization of components that make up organisms, and the evolutionary, developmental and functional relationships among them. Both have been studied at the interspecific (evolutionary) and intraspecific (phenotypic and ontogenetic) levels to different degrees across various clades. Although evolutionary modularity and integration are well-characterized across birds, knowledge of intraspecific patterns is lacking. Here, we use a high-density, three-dimensional geometric morphometric approach to investigate patterns of integration and modularity in Psittacula krameri, a highly successful invasive parrot species that exhibits the derived vertical palate and cranio-facial hinge of the Psittaciformes. Showing a pattern of nine distinct cranial modules, our results support findings from recent research that uses similar methods to investigate interspecific integration in birds. Allometry is not a significant influence on cranial shape variation within this species; however, within-module integration is significantly negatively correlated with disparity, with high variation concentrated in the weakly integrated rostrum, palate and vault modules. As previous studies have demonstrated differences in beak shape between invasive and native populations, variation in the weakly integrated palate and rostrum may have facilitated evolutionary change in these parts of the skull, contributing to the ring-necked parakeet’s success as an invasive species.
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Affiliation(s)
- Matthew J Mitchell
- Department of Life Sciences, Natural History Museum, Kensington, London, UK
- Centre for Integrative Anatomy, Department of Cell and Developmental Biology, University College London, Bloomsbury, London, UK
| | - Anjali Goswami
- Department of Life Sciences, Natural History Museum, Kensington, London, UK
| | - Ryan N Felice
- Centre for Integrative Anatomy, Department of Cell and Developmental Biology, University College London, Bloomsbury, London, UK
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26
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Moore AJ. Vertebral pneumaticity is correlated with serial variation in vertebral shape in storks. J Anat 2021; 238:615-625. [PMID: 32981054 PMCID: PMC7855073 DOI: 10.1111/joa.13322] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 08/23/2020] [Accepted: 09/09/2020] [Indexed: 11/29/2022] Open
Abstract
Birds and their ornithodiran ancestors are unique among vertebrates in exhibiting air-filled sinuses in their postcranial bones, a phenomenon called postcranial skeletal pneumaticity. The factors that account for serial and interspecific variation in postcranial skeletal pneumaticity are poorly understood, although body size, ecology, and bone biomechanics have all been implicated as influencing the extent to which pneumatizing epithelia invade the skeleton and induce bone resorption. Here, I use high-resolution computed-tomography to holistically quantify vertebral pneumaticity in members of the neognath family Ciconiidae (storks), with pneumaticity measured as the relative volume of internal air space. These data are used to describe serial variation in extent of pneumaticity and to assess whether and how pneumaticity varies with the size and shape of a vertebra. Pneumaticity increases dramatically from the middle of the neck onwards, contrary to previous predictions that cervical pneumaticity should decrease toward the thorax to maintain structural integrity as the mass and bending moments of the neck increase. Although the largest vertebrae sampled are also the most pneumatic, vertebral size cannot on its own account for serial or interspecific variation in extent of pneumaticity. Vertebral shape, as quantified by three-dimensional geometric morphometrics, is found to be significantly correlated with extent of pneumaticity, with elongate vertebrae being less pneumatic than craniocaudally short and dorsoventrally tall vertebrae. Considered together, the results of this study are consistent with the hypothesis that shape- and position-specific biomechanics influence the amount of bone loss that can be safely tolerated. These results have potentially important implications for the evolution of vertebral morphology in birds and their extinct relatives.
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Affiliation(s)
- Andrew J. Moore
- Department of Biological SciencesThe George Washington UniversityWashingtonDCUSA,Department of Anatomical SciencesStony Brook UniversityStony BrookNYUSA
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27
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Bjarnason A, Benson R. A 3D geometric morphometric dataset quantifying skeletal variation in birds. ACTA ACUST UNITED AC 2021. [DOI: 10.18563/journal.m3.125] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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28
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Ferrón HG, Martínez-Pérez C, Rahman IA, Selles de Lucas V, Botella H, Donoghue PCJ. Functional assessment of morphological homoplasy in stem-gnathostomes. Proc Biol Sci 2021; 288:20202719. [PMID: 33467997 PMCID: PMC7893270 DOI: 10.1098/rspb.2020.2719] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/22/2020] [Indexed: 11/12/2022] Open
Abstract
Osteostraci and Galeaspida are stem-gnathostomes, occupying a key phylogenetic position for resolving the nature of the jawless ancestor from which jawed vertebrates evolved more than 400 million years ago. Both groups are characterized by the presence of rigid headshields that share a number of common morphological traits, in some cases hindering the resolution of their interrelationships and the exact nature of their affinities with jawed vertebrates. Here, we explore the morphological and functional diversity of osteostracan and galeaspid headshields using geometric morphometrics and computational fluid dynamics to constrain the factors that promoted the evolution of their similar morphologies and informing on the ecological scenario under which jawed vertebrates emerged. Phylomorphospace, Mantel analysis and Stayton metrics demonstrate a high degree of homoplasy. Computational fluid dynamics reveals similar hydrodynamic performance among morphologically convergent species, indicating the independent acquisition of the same morphofunctional traits and, potentially, equivalent lifestyles. These results confirm that a number of the characters typically used to infer the evolutionary relationships among galeaspids, osteostracans and jawed vertebrates are convergent in nature, potentially obscuring understanding of the assembly of the gnathostome bodyplan. Ultimately, our results reveal that while the jawless relatives of the earliest jawed vertebrates were ecologically diverse, widespread convergence on the same hydrodynamic adaptations suggests they had reached the limits of their potential ecological diversity-overcome by jawed vertebrates and their later innovations.
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Affiliation(s)
- Humberto G. Ferrón
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
- Instituto Cavanilles de Biodiversidad i Biología Evolutiva, Universitat de València, C/ Catedrático José Beltrán Martínez, 2, 46980 Paterna, Valencia, Spain
| | - Carlos Martínez-Pérez
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
- Instituto Cavanilles de Biodiversidad i Biología Evolutiva, Universitat de València, C/ Catedrático José Beltrán Martínez, 2, 46980 Paterna, Valencia, Spain
| | - Imran A. Rahman
- Oxford University Museum of Natural History, Parks Road, Oxford OX1 3PW, UK
| | - Víctor Selles de Lucas
- School of Engineering and Computer Science, University of Hull, Cottingham Rd, Hull HU6 7RX, UK
| | - Héctor Botella
- Instituto Cavanilles de Biodiversidad i Biología Evolutiva, Universitat de València, C/ Catedrático José Beltrán Martínez, 2, 46980 Paterna, Valencia, Spain
| | - Philip C. J. Donoghue
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
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29
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MacLeod N, Kolska Horwitz L. Machine-learning strategies for testing patterns of morphological variation in small samples: sexual dimorphism in gray wolf (Canis lupus) crania. BMC Biol 2020; 18:113. [PMID: 32883273 PMCID: PMC7470621 DOI: 10.1186/s12915-020-00832-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 07/20/2020] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Studies of mammalian sexual dimorphism have traditionally involved the measurement of selected dimensions of particular skeletal elements and use of single data-analysis procedures. Consequently, such studies have been limited by a variety of both practical and conceptual constraints. To compare and contrast what might be gained from a more exploratory, multifactorial approach to the quantitative assessment of form-variation, images of a small sample of modern Israeli gray wolf (Canis lupus) crania were analyzed via elliptical Fourier analysis of cranial outlines, a Naïve Bayes machine-learning approach to the analysis of these same outline data, and a deep-learning analysis of whole images in which all aspects of these cranial morphologies were represented. The statistical significance and stability of each discriminant result were tested using bootstrap and jackknife procedures. RESULTS Our results reveal no evidence for statistically significant sexual size dimorphism, but significant sex-mediated shape dimorphism. These are consistent with the findings of prior wolf sexual dimorphism studies and extend these studies by identifying new aspects of dimorphic variation. Additionally, our results suggest that shape-based sexual dimorphism in the C. lupus cranial complex may be more widespread morphologically than had been appreciated by previous researchers. CONCLUSION Our results suggest that size and shape dimorphism can be detected in small samples and may be dissociated in mammalian morphologies. This result is particularly noteworthy in that it implies there may be a need to refine allometric hypothesis tests that seek to account for phenotypic sexual dimorphism. The methods we employed in this investigation are fully generalizable and can be applied to a wide range of biological materials and could facilitate the rapid evaluation of a diverse array of morphological/phenomic hypotheses.
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Affiliation(s)
- Norman MacLeod
- School of Earth Science and Engineering, Zhu Gongshan Building, Nanjing University, 163 Xianlin Avenue, Nanjing, 210023 Jiangsu China
| | - Liora Kolska Horwitz
- National Natural History Collections, Faculty of Life Sciences, The Hebrew University of Jerusalem, The Edmond J. Safra Campus - Givat Ram, 9190401 Jerusalem, Israel
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30
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Clinal and Allometric Variation in the Skull of Sexually Dimorphic Opossums. J MAMM EVOL 2020. [DOI: 10.1007/s10914-020-09513-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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31
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Vrdoljak J, Sanchez KI, Arreola-Ramos R, Diaz Huesa EG, Villagra A, Avila LJ, Morando M. Testing repeatability, measurement error and species differentiation when using geometric morphometrics on complex shapes: a case study of Patagonian lizards of the genus Liolaemus (Squamata: Liolaemini). Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
The repeatability of findings is the key factor behind scientific reliability, and the failure to reproduce scientific findings has been termed the ‘replication crisis’. Geometric morphometrics is an established tool in evolutionary biology. However, different operators (and/or different methods) could act as large sources of variation in the data obtained. Here, we investigated inter-operator error in geometric morphometric protocols on complex shapes of Liolaemus lizards, as well as measurement error in three taxa varying in their difficulty of digitalization. We also examined the potential for these protocols to discriminate among complex shapes in closely related species. We found a wide range of inter-operator error, contributing between 19.5% and 60% to the total variation. Moreover, measurement error increased with the complexity of the quantified shape. All protocols were able to discriminate between species, but the use of more landmarks did not imply better performance. We present evidence that complex shapes reduce repeatability, highlighting the need to explore different sources of variation that could lead to such low repeatability. Lastly, we suggest some recommendations to improve the repeatability and reliability of geometric morphometrics results.
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Affiliation(s)
- Juan Vrdoljak
- Instituto Patagónico para el Estudio de los Ecosistemas Continentales, Consejo Nacional de Investigaciones Científicas y Técnicas (IPEEC-CONICET), Puerto Madryn, Chubut, Argentina
| | - Kevin Imanol Sanchez
- Instituto Patagónico para el Estudio de los Ecosistemas Continentales, Consejo Nacional de Investigaciones Científicas y Técnicas (IPEEC-CONICET), Puerto Madryn, Chubut, Argentina
| | - Roberto Arreola-Ramos
- Instituto Patagónico para el Estudio de los Ecosistemas Continentales, Consejo Nacional de Investigaciones Científicas y Técnicas (IPEEC-CONICET), Puerto Madryn, Chubut, Argentina
| | - Emilce Guadalupe Diaz Huesa
- Instituto de Diversidad y Evolución Austral, Consejo Nacional de Investigaciones Científicas y Técnicas (IDEAUS-CONICET), Puerto Madryn, Chubut, Argentina
| | - Alejandro Villagra
- Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), Puerto Madryn, Chubut, Argentina
| | - Luciano Javier Avila
- Instituto Patagónico para el Estudio de los Ecosistemas Continentales, Consejo Nacional de Investigaciones Científicas y Técnicas (IPEEC-CONICET), Puerto Madryn, Chubut, Argentina
| | - Mariana Morando
- Instituto Patagónico para el Estudio de los Ecosistemas Continentales, Consejo Nacional de Investigaciones Científicas y Técnicas (IPEEC-CONICET), Puerto Madryn, Chubut, Argentina
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32
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Metamorphosis shapes cranial diversity and rate of evolution in salamanders. Nat Ecol Evol 2020; 4:1129-1140. [PMID: 32572219 DOI: 10.1038/s41559-020-1225-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 05/14/2020] [Indexed: 12/21/2022]
Abstract
Metamorphosis is widespread across the animal kingdom and induces fundamental changes in the morphology, habitat and resources used by an organism during its lifetime. Metamorphic species are likely to experience more dynamic selective pressures through ontogeny compared with species with single-phase life cycles, which may drive divergent evolutionary dynamics. Here, we reconstruct the cranial evolution of the salamander using geometric morphometric data from 148 species spanning the order's full phylogenetic, developmental and ecological diversity. We demonstrate that life cycle influences cranial shape diversity and rate of evolution. Shifts in the rate of cranial evolution are consistently associated with transitions from biphasic to either direct-developing or paedomorphic life cycle strategies. Direct-developers exhibit the slowest rates of evolution and the lowest disparity, and paedomorphic species the highest. Species undergoing complete metamorphosis (biphasic and direct-developing) exhibit greater cranial modularity (evolutionary independence among regions) than do paedomorphic species, which undergo differential metamorphosis. Biphasic and direct-developing species also display elevated disparity relative to the evolutionary rate for bones associated with feeding, whereas this is not the case for paedomorphic species. Metamorphosis has profoundly influenced salamander cranial evolution, requiring greater autonomy of cranial elements and facilitating the rapid evolution of regions that are remodelled through ontogeny. Rather than compounding functional constraints on variation, metamorphosis seems to have promoted the morphological evolution of salamanders over 180 million years, which may explain the ubiquity of this complex life cycle strategy across disparate organisms.
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33
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The Occasional Perils of Reflection (Across the Midline; in Geometric Morphometrics). Evol Biol 2020. [DOI: 10.1007/s11692-020-09501-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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34
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Bon M, Bardua C, Goswami A, Fabre AC. Cranial integration in the fire salamander, Salamandra salamandra (Caudata: Salamandridae). Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Abstract
Phenotypic integration and modularity are concepts that represent the pattern of connectivity of morphological structures within an organism. Integration describes the coordinated variation of traits, and analyses of these relationships among traits often reveals the presence of modules, sets of traits that are highly integrated but relatively independent of other traits. Phenotypic integration and modularity have been studied at both the evolutionary and static level across a variety of clades, although most studies thus far are focused on amniotes, and especially mammals. Using a high-dimensional geometric morphometric approach, we investigated the pattern of cranial integration and modularity of the Italian fire salamander (Salamandra salamandra giglioli). We recovered a highly modular pattern, but this pattern did not support either entirely developmental or functional hypotheses of cranial organisation, possibly reflecting complex interactions amongst multiple influencing factors. We found that size had no significant effect on cranial shape, and that morphological variance of individual modules had no significant relationship with degree of within-module integration. The pattern of cranial integration in the fire salamander is similar to that previously recovered for caecilians, with highly integrated jaw suspensorium and occipital regions, suggesting possible conservation of patterns across lissamphibians.
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Affiliation(s)
- Margot Bon
- Department of Life Sciences, Natural History Museum, Kensington, London, UK
| | - Carla Bardua
- Department of Life Sciences, Natural History Museum, Kensington, London, UK
- Department of Genetics, Evolution & Environment, University College London, Bloomsbury, London, UK
| | - Anjali Goswami
- Department of Life Sciences, Natural History Museum, Kensington, London, UK
| | - Anne-Claire Fabre
- Department of Life Sciences, Natural History Museum, Kensington, London, UK
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35
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Cardini A, Chiapelli M. How flat can a horse be? Exploring 2D approximations of 3D crania in equids. ZOOLOGY 2020; 139:125746. [PMID: 32086141 DOI: 10.1016/j.zool.2020.125746] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 01/15/2020] [Accepted: 01/16/2020] [Indexed: 01/13/2023]
Abstract
Quantitative analyses of morphological variation using geometric morphometrics are often performed on 2D photos of 3D structures. It is generally assumed that the error due to the flattening of the third dimension is negligible. However, despite hundreds of 2D studies, few have actually tested this assumption and none has done it on large animals, such as those typically classified as megafauna. We explore this issue in living equids, focusing on ventral cranial variation at both micro- and macro-evolutionary levels. By comparing 2D and 3D data, we found that size is well approximated, whereas shape is more strongly impacted by 2D inaccuracies, as it is especially evident in intra-specific analyses. The 2D approximation improves when shape differences are larger, as in macroevolution, but even at this level precise inter-individual similarity relationships are altered. Despite this, main patterns of sex, species and allometric variation in 2D were the same as in 3D, thus suggesting that 2D may be a source of 'noise' that does not mask the main signal in the data. However, the picture that emerges from this and other recent studies on 2D approximation of 3D structures is complex and any generalization premature. Morphometricians should therefore test the appropriateness of 2D using preliminary investigations in relation to the specific study questions in their own samples. We discuss whether this might be feasible using a reduced landmark configuration and smaller samples, which would save time and money. In an exploratory analysis, we found that in equids results seem robust to sampling, but become less precise and, with fewer landmarks, may slightly overestimate 2D inaccuracies.
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Affiliation(s)
- Andrea Cardini
- Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, Via Campi 103, 41125, Modena, Italy; Centre for Forensic Anatomy and Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.
| | - Marika Chiapelli
- Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, Via Campi 103, 41125, Modena, Italy
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36
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Felice RN, Watanabe A, Cuff AR, Noirault E, Pol D, Witmer LM, Norell MA, O'Connor PM, Goswami A. Evolutionary Integration and Modularity in the Archosaur Cranium. Integr Comp Biol 2019; 59:371-382. [PMID: 31120528 DOI: 10.1093/icb/icz052] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Complex structures, like the vertebrate skull, are composed of numerous elements or traits that must develop and evolve in a coordinated manner to achieve multiple functions. The strength of association among phenotypic traits (i.e., integration), and their organization into highly-correlated, semi-independent subunits termed modules, is a result of the pleiotropic and genetic correlations that generate traits. As such, patterns of integration and modularity are thought to be key factors constraining or facilitating the evolution of phenotypic disparity by influencing the patterns of variation upon which selection can act. It is often hypothesized that selection can reshape patterns of integration, parceling single structures into multiple modules or merging ancestrally semi-independent traits into a strongly correlated unit. However, evolutionary shifts in patterns of trait integration are seldom assessed in a unified quantitative framework. Here, we quantify patterns of evolutionary integration among regions of the archosaur skull to investigate whether patterns of cranial integration are conserved or variable across this diverse group. Using high-dimensional geometric morphometric data from 3D surface scans and computed tomography scans of modern birds (n = 352), fossil non-avian dinosaurs (n = 27), and modern and fossil mesoeucrocodylians (n = 38), we demonstrate that some aspects of cranial integration are conserved across these taxonomic groups, despite their major differences in cranial form, function, and development. All three groups are highly modular and consistently exhibit high integration within the occipital region. However, there are also substantial divergences in correlation patterns. Birds uniquely exhibit high correlation between the pterygoid and quadrate, components of the cranial kinesis apparatus, whereas the non-avian dinosaur quadrate is more closely associated with the jugal and quadratojugal. Mesoeucrocodylians exhibit a slightly more integrated facial skeleton overall than the other grades. Overall, patterns of trait integration are shown to be stable among archosaurs, which is surprising given the cranial diversity exhibited by the clade. At the same time, evolutionary innovations such as cranial kinesis that reorganize the structure and function of complex traits can result in modifications of trait correlations and modularity.
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Affiliation(s)
- Ryan N Felice
- Centre for Integrative Anatomy, Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK.,Life Sciences Department, Vertebrates Division, Natural History Museum, London, SW7 5BD, UK
| | - Akinobu Watanabe
- Life Sciences Department, Vertebrates Division, Natural History Museum, London, SW7 5BD, UK.,Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY 11568, USA.,Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
| | - Andrew R Cuff
- Structure and Motion Laboratory, Department of Comparative Biomedical Sciences, Royal Veterinary College, Hawkshead Lane, North Mymms, Hertfordshire, AL9 7TA, UK
| | - Eve Noirault
- Life Sciences Department, Vertebrates Division, Natural History Museum, London, SW7 5BD, UK
| | - Diego Pol
- CONICET. Museo Paleontológico Egidio Feruglio, Av. Fontana 140, Trelew, Chubut, U9100GYO, Argentina
| | - Lawrence M Witmer
- Department of Biomedical Sciences, Ohio University Heritage College of Osteopathic Medicine, Athens, OH, USA
| | - Mark A Norell
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
| | - Patrick M O'Connor
- Department of Biomedical Sciences, Ohio University Heritage College of Osteopathic Medicine, Athens, OH, USA.,Ohio Center for Ecology and Evolutionary Studies, Ohio University, Athens, OH, USA
| | - Anjali Goswami
- Life Sciences Department, Vertebrates Division, Natural History Museum, London, SW7 5BD, UK.,Department of Genetics, Evolution, and Environment, University College London, London, WC1E 6BT, UK
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37
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Drumheller SK, Wilberg EW. A synthetic approach for assessing the interplay of form and function in the crocodyliform snout. Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zlz081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Existing classifications of snout shape within Crocodylia are supported by functional studies, but ecological surveys often reveal a higher than expected diversity of prey items within putatively specialist groups, and research into bite force and predation behaviour does not always reveal significant differences between snout shape groups. The addition of more distantly related crocodyliforms complicates the ecomorphological signal, because these groups often occupy a larger area of morphospace than the crown group alone. Here, we present an expanded classification of snout shapes and diets across Crocodyliformes, bringing together geometric morphometrics, non-hierarchical cluster analyses, phylogenetic analyses, ancestral state reconstructions, ecological surveys of diet, and feeding traces from the fossil record to build and test predictive models for linking snout shape and function across the clade. When applied to living members of the group, these new classifications partition out based on differences in predator body mass and maximal prey size. When applied to fossils, these classifications predict potential prey items and identify possible examples of scavenging. In a phylogenetic context, these ecomorphs reveal differences in dietary strategies and diversity within major crocodyliform clades. Taken together, these patterns suggest that crocodyliform diversity, in terms of both morphology and diet, has been underestimated.
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Affiliation(s)
- Stephanie K Drumheller
- Department of Earth and Planetary Sciences, University of Tennessee–Knoxville, Knoxville, TN, USA
| | - Eric W Wilberg
- Department of Anatomical Sciences, Stony Brook University, Health Sciences Center, Stony Brook, NY, USA
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38
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Djurakic MR, Milankov VR. The utility of plastron shape for uncovering cryptic diversity in Hermann's tortoise. J Zool (1987) 2019. [DOI: 10.1111/jzo.12736] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. R. Djurakic
- Department of Biology and Ecology Faculty of Sciences University of Novi Sad Novi Sad Serbia
| | - V. R. Milankov
- Department of Biology and Ecology Faculty of Sciences University of Novi Sad Novi Sad Serbia
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39
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The Shape of Weaver: Investigating Shape Disparity in Orb-Weaving Spiders (Araneae, Araneidae) Using Geometric Morphometrics. Evol Biol 2019. [DOI: 10.1007/s11692-019-09482-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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40
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Cordero GA, Stearns S, Quinteros K, Berns CM, Binz SM, Janzen F. The postembryonic transformation of the shell in emydine box turtles. Evol Dev 2019; 21:297-310. [PMID: 31441599 DOI: 10.1111/ede.12307] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A key trend in the 210-million-year-old history of modern turtles was the evolution of shell kinesis, that is, shell movement during neck and limb retraction. Kinesis is hypothesized to enhance predator defense in small terrestrial and semiaquatic turtles and has evolved multiple times since the early Cretaceous. This complex phenotype is nonfunctional and far from fully differentiated following embryogenesis. Instead, kinesis develops slowly in juveniles, providing a unique opportunity to illustrate the postembryonic origins of an adaptive trait. To this end, we examined ventral shell (plastral) kinesis in emydine box turtles and found that hatchling plastron shape differs from that of akinetic-shelled relatives, particularly where the hinge that enables kinesis differentiates. We also demonstrated shape changes relative to plastron size in juveniles, coinciding with a shift in the carapace-plastron structural connection, rearrangement of ectodermal plates, and bone repatterning. Furthermore, because the shell grows larger relative to the head, complete concealment of the head and extremities is only achieved after relative shell proportions increase. Structural alterations that facilitate the box turtle's transformation are probably prepatterned in embryos but require function-induced changes to differentiate in juveniles. This mode of delayed trait differentiation is essential to phenotypic diversification in turtles and perhaps other tetrapods.
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Affiliation(s)
- Gerardo A Cordero
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA.,Department of Geosciences, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Samantha Stearns
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
| | - Kevin Quinteros
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
| | - Chelsea M Berns
- Department of Biology, Salisbury University, Salisbury, Maryland, USA
| | - Steven M Binz
- Department of Physics, Salisbury University, Salisbury, Maryland, USA
| | - Fredric Janzen
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
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41
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Bardua C, Felice RN, Watanabe A, Fabre AC, Goswami A. A Practical Guide to Sliding and Surface Semilandmarks in Morphometric Analyses. Integr Org Biol 2019; 1:obz016. [PMID: 33791531 PMCID: PMC7780474 DOI: 10.1093/iob/obz016] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Advances in imaging technologies, such as computed tomography (CT) and surface scanning, have facilitated the rapid generation of large datasets of high-resolution three-dimensional (3D) specimen reconstructions in recent years. The wealth of phenotypic information available from these datasets has the potential to inform our understanding of morphological variation and evolution. However, the ever-increasing ease of compiling 3D datasets has created an urgent need for sophisticated methods of capturing high-density shape data that reflect the biological complexity in form. Landmarks often do not take full advantage of the rich shape information available from high-resolution 3D specimen reconstructions, as they are typically restricted to sutures or processes that can be reliably identified across specimens and exclude most of the surface morphology. The development of sliding and surface semilandmark techniques has greatly enhanced the quantification of shape, but their application to diverse datasets can be challenging, especially when dealing with the variable absence of some regions within a structure. Using comprehensive 3D datasets of crania that span the entire clades of birds, squamates and caecilians, we demonstrate methods for capturing morphology across incredibly diverse shapes. We detail many of the difficulties associated with applying semilandmarks to comparable regions across highly disparate structures, and provide solutions to some of these challenges, while considering the consequences of decisions one makes in applying these approaches. Finally, we analyze the benefits of high-density sliding semilandmark approaches over landmark-only studies for capturing shape across diverse organisms and discuss the promise of these approaches for the study of organismal form.
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Affiliation(s)
- C Bardua
- Department of Life Sciences, Natural History Museum, Cromwell Rd, Kensington, London, SW7 5BD, UK.,Department of Genetics, Evolution & Environment, University College London, Gower St, Bloomsbury, London, WC1E 6BT, UK
| | - R N Felice
- Centre for Integrative Anatomy, Department of Cell and Developmental Biology, University College London, Gower St, Bloomsbury, London, WC1E 6BT, UK
| | - A Watanabe
- Department of Life Sciences, Natural History Museum, Cromwell Rd, Kensington, London, SW7 5BD, UK.,Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, Northern Blvd, Old Westbury, NY 11568, USA.,Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA
| | - A-C Fabre
- Department of Life Sciences, Natural History Museum, Cromwell Rd, Kensington, London, SW7 5BD, UK
| | - A Goswami
- Department of Life Sciences, Natural History Museum, Cromwell Rd, Kensington, London, SW7 5BD, UK.,Department of Genetics, Evolution & Environment, University College London, Gower St, Bloomsbury, London, WC1E 6BT, UK
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42
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Pokhojaev A, Avni H, Sella-Tunis T, Sarig R, May H. Changes in human mandibular shape during the Terminal Pleistocene-Holocene Levant. Sci Rep 2019; 9:8799. [PMID: 31217474 PMCID: PMC6584575 DOI: 10.1038/s41598-019-45279-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 06/04/2019] [Indexed: 11/16/2022] Open
Abstract
The transition to food production, exploitation of 'secondary' products (e.g., milk), and advances in cookware technology have affected all aspects of human life. The aim of the present study was to follow changes in mandibular form and shape throughout the terminal Pleistocene-Holocene Levant. The hemimandibles of four populations were included in this study: Natufian hunter-gatherers (n = 10), Pre-pottery Neolithic early farmers (n = 6), Chalcolithic farmers (n = 9), Roman-Byzantine (n = 16), and modern (n = 63) populations. A surface mesh of each mandible was reconstructed from CT or surface scans. Changes in mandibular form and shape were studied using the Procrustes-based geometric morphometrics method. Univariate and multivariate analyses were carried out to examine differences in size and shape between the studied populations. Our results reveal considerable temporal changes in mandibular shape throughout the Holocene Levant, mainly between the pre-agricultural population (the Natufian) and the succeeding ones, and between the post-industrial (the Modern) and the pre-industrial populations. A tendency for a reduction in mandibular size was identified between the pre-agricultural population and the farmers. Most regions of the mandible underwent shape changes. In conclusion, substantial changes in mandibular shape occurred throughout the Holocene Levant, especially following the agricultural revolution. These changes can be explained by the "masticatory-functional hypothesis".
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Affiliation(s)
- Ariel Pokhojaev
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
- Shmunis Family Anthropology Institute, Dan David Center for Human Evolution and Biohistory Research, Sackler Faculty of Medicine, Steinhardt Natural History Museum, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
- Departments of Orthodontics and Oral Biology, The Maurice and Gabriela Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
| | - Hadas Avni
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
- Shmunis Family Anthropology Institute, Dan David Center for Human Evolution and Biohistory Research, Sackler Faculty of Medicine, Steinhardt Natural History Museum, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
| | - Tatiana Sella-Tunis
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
- Shmunis Family Anthropology Institute, Dan David Center for Human Evolution and Biohistory Research, Sackler Faculty of Medicine, Steinhardt Natural History Museum, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
- Departments of Orthodontics and Oral Biology, The Maurice and Gabriela Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
| | - Rachel Sarig
- Shmunis Family Anthropology Institute, Dan David Center for Human Evolution and Biohistory Research, Sackler Faculty of Medicine, Steinhardt Natural History Museum, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
- Departments of Orthodontics and Oral Biology, The Maurice and Gabriela Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
| | - Hila May
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel.
- Shmunis Family Anthropology Institute, Dan David Center for Human Evolution and Biohistory Research, Sackler Faculty of Medicine, Steinhardt Natural History Museum, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel.
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43
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Stayton CT. Performance in three shell functions predicts the phenotypic distribution of hard-shelled turtles. Evolution 2019; 73:720-734. [PMID: 30820948 DOI: 10.1111/evo.13709] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 01/28/2019] [Indexed: 01/30/2023]
Abstract
Adaptive landscapes have served as fruitful guides to evolutionary research for nearly a century. Current methods guided by landscape frameworks mostly utilize evolutionary modeling (e.g., fitting data to Ornstein-Uhlenbeck models) to make inferences about adaptive peaks. Recent alternative methods utilize known relationships between phenotypes and functional performance to derive information about adaptive landscapes; this information can then help explain the distribution of species in phenotypic space and help infer the relative importance of various functions for guiding diversification. Here, data on performance for three turtle shell functions-strength, hydrodynamic efficiency, and self-righting ability-are used to develop a set of predicted performance optima in shell shape space. The distribution of performance optima shows significant similarity to the distribution of existing turtle species and helps explain the absence of shells in otherwise anomalously empty regions of morphospace. The method outperforms a modeling-based approach in inferring the location of reasonable adaptive peaks and in explaining the shape of the phenotypic distributions of turtle shells. Performance surface-based methods allow researchers to more directly connect functional performance with macroevolutionary diversification, and to explain the distribution of species (including presences and absences) across phenotypic space.
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Affiliation(s)
- C Tristan Stayton
- Department of Biology, Bucknell University, Lewisburg, Pennsylvania, 17837
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44
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Watanabe A, Gignac PM, Balanoff AM, Green TL, Kley NJ, Norell MA. Are endocasts good proxies for brain size and shape in archosaurs throughout ontogeny? J Anat 2019; 234:291-305. [PMID: 30506962 PMCID: PMC6365484 DOI: 10.1111/joa.12918] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2018] [Indexed: 12/21/2022] Open
Abstract
Cranial endocasts, or the internal molds of the braincase, are a crucial correlate for investigating the neuroanatomy of extinct vertebrates and tracking brain evolution through deep time. Nevertheless, the validity of such studies pivots on the reliability of endocasts as a proxy for brain morphology. Here, we employ micro-computed tomography imaging, including diffusible iodine-based contrast-enhanced CT, and a three-dimensional geometric morphometric framework to examine both size and shape differences between brains and endocasts of two exemplar archosaur taxa - the American alligator (Alligator mississippiensis) and the domestic chicken (Gallus gallus). With ontogenetic sampling, we quantitatively evaluate how endocasts differ from brains and whether this deviation changes during development. We find strong size and shape correlations between brains and endocasts, divergent ontogenetic trends in the brain-to-endocast correspondence between alligators and chickens, and a comparable magnitude between brain-endocast shape differences and intraspecific neuroanatomical variation. The results have important implications for paleoneurological studies in archosaurs. Notably, we demonstrate that the pattern of endocranial shape variation closely reflects brain shape variation. Therefore, analyses of endocranial morphology are unlikely to generate spurious conclusions about large-scale trends in brain size and shape. To mitigate any artifacts, however, paleoneurological studies should consider the lower brain-endocast correspondence in the hindbrain relative to the forebrain; higher size and shape correspondences in chickens than alligators throughout postnatal ontogeny; artificially 'pedomorphic' shape of endocasts relative to their corresponding brains; and potential biases in both size and shape data due to the lack of control for ontogenetic stages in endocranial sampling.
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Affiliation(s)
- Akinobu Watanabe
- Department of AnatomyNew York Institute of Technology College of Osteopathic MedicineOld WestburyNYUSA
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
- Richard Gilder Graduate SchoolAmerican Museum of Natural HistoryNew YorkNYUSA
- Department of Life Sciences Vertebrates DivisionNatural History MuseumLondonUK
| | - Paul M. Gignac
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
- Department of Anatomy and Cell BiologyOklahoma State University Center for Health SciencesTulsaOKUSA
| | - Amy M. Balanoff
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
- Center for Functional Anatomy and EvolutionJohns Hopkins University School of MedicineBaltimoreMDUSA
| | - Todd L. Green
- Department of Anatomy and Cell BiologyOklahoma State University Center for Health SciencesTulsaOKUSA
| | - Nathan J. Kley
- Department of Anatomical SciencesStony Brook UniversityStony BrookNYUSA
| | - Mark A. Norell
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNYUSA
- Richard Gilder Graduate SchoolAmerican Museum of Natural HistoryNew YorkNYUSA
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45
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How many landmarks are enough to characterize shape and size variation? PLoS One 2018; 13:e0198341. [PMID: 29864151 PMCID: PMC5986137 DOI: 10.1371/journal.pone.0198341] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 05/17/2018] [Indexed: 11/19/2022] Open
Abstract
Accurate characterization of morphological variation is crucial for generating reliable results and conclusions concerning changes and differences in form. Despite the prevalence of landmark-based geometric morphometric (GM) data in the scientific literature, a formal treatment of whether sampled landmarks adequately capture shape variation has remained elusive. Here, I introduce LaSEC (Landmark Sampling Evaluation Curve), a computational tool to assess the fidelity of morphological characterization by landmarks. This task is achieved by calculating how subsampled data converge to the pattern of shape variation in the full dataset as landmark sampling is increased incrementally. While the number of landmarks needed for adequate shape variation is dependent on individual datasets, LaSEC helps the user (1) identify under- and oversampling of landmarks; (2) assess robustness of morphological characterization; and (3) determine the number of landmarks that can be removed without compromising shape information. In practice, this knowledge could reduce time and cost associated with data collection, maintain statistical power in certain analyses, and enable the incorporation of incomplete, but important, specimens to the dataset. Results based on simulated shape data also reveal general properties of landmark data, including statistical consistency where sampling additional landmarks has the tendency to asymptotically improve the accuracy of morphological characterization. As landmark-based GM data become more widely adopted, LaSEC provides a systematic approach to evaluate and refine the collection of shape data--a goal paramount for accumulation and analysis of accurate morphological information.
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46
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Quantifying the shape variation of the elytra in Patagonian populations of the ground beetle Ceroglossus chilensis (Coleoptera: Carabidae). ZOOL ANZ 2018. [DOI: 10.1016/j.jcz.2018.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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47
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Alhajeri BH, Steppan SJ. Disparity and Evolutionary Rate Do Not Explain Diversity Patterns in Muroid Rodents (Rodentia: Muroidea). Evol Biol 2018. [DOI: 10.1007/s11692-018-9453-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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48
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Vitek NS. Delineating modern variation from extinct morphology in the fossil record using shells of the Eastern Box Turtle (Terrapene carolina). PLoS One 2018; 13:e0193437. [PMID: 29513709 PMCID: PMC5841793 DOI: 10.1371/journal.pone.0193437] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 02/09/2018] [Indexed: 11/30/2022] Open
Abstract
Characterization of morphological variation in the shells of extant Eastern Box Turtles, Terrapene carolina, provides a baseline for comparison to fossil populations. It also provides an example of the difficulties inherent to recognizing intraspecific diversity in the fossil record. The degree to which variation in fossils of T. carolina can be accommodated by extant variation in the species has been disagreed upon for over eighty years. Using morphometric analyses of the carapace, I address the relationship between modern and fossil T. carolina in terms of sexual dimorphism, geographic and subspecific variation, and allometric variation. Modern T. carolina display weak male-biased sexual size dimorphism. Sexual shape dimorphism cannot be reliably detected in the fossil record. Rather than a four-part subspecific division, patterns of geographic variation are more consistent with clinal variation between various regions in the species distribution. Allometric patterns are qualitatively similar to those documented in other emydid turtles and explain a significant amount of shape variation. When allometric patterns are accounted for, Holocene specimens are not significantly different from modern specimens. In contrast, several geologically older specimens have significantly different carapace shape with no modern analogue. Those large, fossilized specimens represent extinct variation occupying novel portions of morphospace. This study highlights the need for additional documentation of modern osteological variation that can be used to test hypotheses of intraspecific evolution in the fossil record.
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Affiliation(s)
- Natasha S. Vitek
- Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas, Florida Museum of Natural History and Department of Biology, the University of Florida, Gainesville, Florida, United States of America
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49
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Patterns of integration in the canine skull: an inside view into the relationship of the skull modules of domestic dogs and wolves. ZOOLOGY 2017; 125:1-9. [DOI: 10.1016/j.zool.2017.06.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 06/02/2017] [Accepted: 06/02/2017] [Indexed: 12/27/2022]
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50
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Hernandez G, Garcia S, Vilela JF, de la Sancha NU. Ontogenetic variation of an omnivorous generalist rodent: the case of the montane akodont (Akodon montensis). J Mammal 2017. [DOI: 10.1093/jmammal/gyx135] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Affiliation(s)
- Gabriel Hernandez
- Department of Biological Sciences, Chicago State University, 9501 S. King Drive, Chicago, IL 60628, USA (GH, NUDLS)
- Integrative Research Center, The Field Museum of Natural History, 1400 S. Lake Shore Drive, Chicago, IL 60605, USA (GH, JFV, NUDLS)
| | - Soraida Garcia
- Department of Ecological Sciences and Engineering, Purdue University, 610 Purdue Mall, West Lafayette, IN 47907, USA (SG)
| | - Júlio F Vilela
- Integrative Research Center, The Field Museum of Natural History, 1400 S. Lake Shore Drive, Chicago, IL 60605, USA (GH, JFV, NUDLS)
| | - Noé U de la Sancha
- Department of Biological Sciences, Chicago State University, 9501 S. King Drive, Chicago, IL 60628, USA (GH, NUDLS)
- Integrative Research Center, The Field Museum of Natural History, 1400 S. Lake Shore Drive, Chicago, IL 60605, USA (GH, JFV, NUDLS)
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