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Tse YT, Miller CV, Pittman M. Morphological disparity and structural performance of the dromaeosaurid skull informs ecology and evolutionary history. BMC Ecol Evol 2024; 24:39. [PMID: 38622512 PMCID: PMC11020771 DOI: 10.1186/s12862-024-02222-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 03/11/2024] [Indexed: 04/17/2024] Open
Abstract
Non-avialan theropod dinosaurs had diverse ecologies and varied skull morphologies. Previous studies of theropod cranial morphology mostly focused on higher-level taxa or characteristics associated with herbivory. To better understand morphological disparity and function within carnivorous theropod families, here we focus on the Dromaeosauridae, 'raptors' traditionally seen as agile carnivorous hunters.We applied 2D geometric morphometrics to quantify skull shape, performed mechanical advantage analysis to assess the efficiency of bite force transfer, and performed finite element analysis to examine strain distribution in the skull during biting. We find that dromaeosaurid skull morphology was less disparate than most non-avialan theropod groups. Their skulls show a continuum of form between those that are tall and short and those that are flat and long. We hypothesise that this narrower morphological disparity indicates developmental constraint on skull shape, as observed in some mammalian families. Mechanical advantage indicates that Dromaeosaurus albertensis and Deinonychus antirrhopus were adapted for relatively high bite forces, while Halszkaraptor escuilliei was adapted for high bite speed, and other dromaeosaurids for intermediate bite forces and speeds. Finite element analysis indicates regions of high strain are consistent within dromaeosaurid families but differ between them. Average strain levels do not follow any phylogenetic pattern, possibly due to ecological convergence between distantly-related taxa.Combining our new morphofunctional data with a re-evaluation of previous evidence, we find piscivorous reconstructions of Halszkaraptor escuilliei to be unlikely, and instead suggest an invertivorous diet and possible adaptations for feeding in murky water or other low-visibility conditions. We support Deinonychus antirrhopus as being adapted for taking large vertebrate prey, but we find that its skull is relatively less resistant to bite forces than other dromaeosaurids. Given the recovery of high bite force resistance for Velociraptor mongoliensis, which is believed to have regularly engaged in scavenging behaviour, we suggest that higher bite force resistance in a dromaeosaurid taxon may reflect a greater reliance on scavenging rather than fresh kills.Comparisons to the troodontid Gobivenator mongoliensis suggest that a gracile rostrum like that of Velociraptor mongoliensis is ancestral to their closest common ancestor (Deinonychosauria) and the robust rostra of Dromaeosaurus albertensis and Deinonychus antirrhopus are a derived condition. Gobivenator mongoliensis also displays a higher jaw mechanical advantage and lower resistance to bite force than the examined dromaeosaurids, but given the hypothesised ecological divergence of troodontids from dromaeosaurids it is unclear which group, if either, represents the ancestral condition. Future work extending sampling to troodontids would therefore be invaluable and provide much needed context to the origin of skull form and function in early birds. This study illustrates how skull shape and functional metrics can discern non-avialan theropod ecology at lower taxonomic levels and identify variants of carnivorous feeding.
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Affiliation(s)
- Yuen Ting Tse
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Case Vincent Miller
- Department of Earth Sciences, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Michael Pittman
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
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2
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Mitchell DR, Sherratt E, Weisbecker V. Facing the facts: adaptive trade-offs along body size ranges determine mammalian craniofacial scaling. Biol Rev Camb Philos Soc 2024; 99:496-524. [PMID: 38029779 DOI: 10.1111/brv.13032] [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: 03/27/2023] [Revised: 11/12/2023] [Accepted: 11/14/2023] [Indexed: 12/01/2023]
Abstract
The mammalian cranium (skull without lower jaw) is representative of mammalian diversity and is thus of particular interest to mammalian biologists across disciplines. One widely retrieved pattern accompanying mammalian cranial diversification is referred to as 'craniofacial evolutionary allometry' (CREA). This posits that adults of larger species, in a group of closely related mammals, tend to have relatively longer faces and smaller braincases. However, no process has been officially suggested to explain this pattern, there are many apparent exceptions, and its predictions potentially conflict with well-established biomechanical principles. Understanding the mechanisms behind CREA and causes for deviations from the pattern therefore has tremendous potential to explain allometry and diversification of the mammalian cranium. Here, we propose an amended framework to characterise the CREA pattern more clearly, in that 'longer faces' can arise through several kinds of evolutionary change, including elongation of the rostrum, retraction of the jaw muscles, or a more narrow or shallow skull, which all result in a generalised gracilisation of the facial skeleton with increased size. We define a standardised workflow to test for the presence of the pattern, using allometric shape predictions derived from geometric morphometrics analysis, and apply this to 22 mammalian families including marsupials, rabbits, rodents, bats, carnivores, antelopes, and whales. Our results show that increasing facial gracility with size is common, but not necessarily as ubiquitous as previously suggested. To address the mechanistic basis for this variation, we then review cranial adaptations for harder biting. These dictate that a more gracile cranium in larger species must represent a structural sacrifice in the ability to produce or withstand harder bites, relative to size. This leads us to propose that facial gracilisation in larger species is often a product of bite force allometry and phylogenetic niche conservatism, where more closely related species tend to exhibit more similar feeding ecology and biting behaviours and, therefore, absolute (size-independent) bite force requirements. Since larger species can produce the same absolute bite forces as smaller species with less effort, we propose that relaxed bite force demands can permit facial gracility in response to bone optimisation and alternative selection pressures. Thus, mammalian facial scaling represents an adaptive by-product of the shifting importance of selective pressures occurring with increased size. A reverse pattern of facial 'shortening' can accordingly also be found, and is retrieved in several cases here, where larger species incorporate novel feeding behaviours involving greater bite forces. We discuss multiple exceptions to a bite force-mediated influence on facial proportions across mammals which lead us to argue that ecomorphological specialisation of the cranium is likely to be the primary driver of facial scaling patterns, with some developmental constraints as possible secondary factors. A potential for larger species to have a wider range of cranial functions when less constrained by bite force demands might also explain why selection for larger sizes seems to be prevalent in some mammalian clades. The interplay between adaptation and constraint across size ranges thus presents an interesting consideration for a mechanistically grounded investigation of mammalian cranial allometry.
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Affiliation(s)
- D Rex Mitchell
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, New South Wales, 2522, Australia
| | - Emma Sherratt
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, 5005, Australia
- South Australian Museum, Adelaide, South Australia, 5000, Australia
| | - Vera Weisbecker
- College of Science and Engineering, Flinders University, GPO Box 2100, Adelaide, South Australia, 5001, Australia
- Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, Wollongong, New South Wales, 2522, Australia
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3
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Law CJ, Hlusko LJ, Tseng ZJ. Uncovering the mosaic evolution of the carnivoran skeletal system. Biol Lett 2024; 20:20230526. [PMID: 38263882 PMCID: PMC10806395 DOI: 10.1098/rsbl.2023.0526] [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: 11/09/2023] [Accepted: 12/21/2023] [Indexed: 01/25/2024] Open
Abstract
The diversity of vertebrate skeletons is often attributed to adaptations to distinct ecological factors such as diet, locomotion, and sensory environment. Although the adaptive evolution of skull, appendicular skeleton, and vertebral column is well studied in vertebrates, comprehensive investigations of all skeletal components simultaneously are rarely performed. Consequently, we know little of how modes of evolution differ among skeletal components. Here, we tested if ecological and phylogenetic effects led to distinct modes of evolution among the cranial, appendicular and vertebral regions in extant carnivoran skeletons. Using multivariate evolutionary models, we found mosaic evolution in which only the mandible, hindlimb and posterior (i.e. last thoracic and lumbar) vertebrae showed evidence of adaptation towards ecological regimes whereas the remaining skeletal components reflect clade-specific evolutionary shifts. We hypothesize that the decoupled evolution of individual skeletal components may have led to the origination of distinct adaptive zones and morphologies among extant carnivoran families that reflect phylogenetic hierarchies. Overall, our work highlights the importance of examining multiple skeletal components simultaneously in ecomorphological analyses. Ongoing work integrating the fossil and palaeoenvironmental record will further clarify deep-time drivers that govern the carnivoran diversity we see today and reveal the complexity of evolutionary processes in multicomponent systems.
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Affiliation(s)
- Chris J. Law
- Department of Integrative Biology, University of Texas, Austin, TX, USA
- Burke Museum and Department of Biology, University of Washington, Seattle, WA, USA
- Department of Integrative Biology, University of California, Berkeley, CA, USA
| | - Leslea J. Hlusko
- National Research Center on Human Evolution (CENIEH), Burgos, Spain
| | - Z. Jack Tseng
- Department of Integrative Biology, University of California, Berkeley, CA, USA
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4
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Schwab JA, Figueirido B, Martín-Serra A, van der Hoek J, Flink T, Kort A, Esteban Núñez JM, Jones KE. Evolutionary ecomorphology for the twenty-first century: examples from mammalian carnivores. Proc Biol Sci 2023; 290:20231400. [PMID: 38018109 PMCID: PMC10685142 DOI: 10.1098/rspb.2023.1400] [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: 06/21/2023] [Accepted: 11/06/2023] [Indexed: 11/30/2023] Open
Abstract
Carnivores (cats, dogs and kin) are a diverse group of mammals that inhabit a remarkable range of ecological niches. While the relationship between ecology and morphology has long been of interest in carnivorans, the application of quantitative techniques has resulted in a recent explosion of work in the field. Therefore, they provide a case study of how quantitative techniques, such as geometric morphometrics (GMM), have impacted our ability to tease apart complex ecological signals from skeletal anatomy, and the implications for our understanding of the relationships between form, function and ecological specialization. This review provides a synthesis of current research on carnivoran ecomorphology, with the goal of illustrating the complex interaction between ecology and morphology in the skeleton. We explore the ecomorphological diversity across major carnivoran lineages and anatomical systems. We examine cranial elements (skull, sensory systems) and postcranial elements (limbs, vertebral column) to reveal mosaic patterns of adaptation related to feeding and hunting strategies, locomotion and habitat preference. We highlight the crucial role that new approaches have played in advancing our understanding of carnivoran ecomorphology, while addressing challenges that remain in the field, such as ecological classifications, form-function relationships and multi-element analysis, offering new avenues for future research.
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Affiliation(s)
- Julia A. Schwab
- Department of Earth and Environmental Sciences, University of Manchester, M13 9PL Manchester, UK
| | - Borja Figueirido
- Departamento de Ecología y Geología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Alberto Martín-Serra
- Departamento de Ecología y Geología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain
| | - Julien van der Hoek
- Department of Earth and Environmental Sciences, University of Manchester, M13 9PL Manchester, UK
| | - Therese Flink
- Department of Palaeobiology, Swedish Museum of Natural History, PO Box 50007, 10405 Stockholm, Sweden
| | - Anne Kort
- Department of Earth and Atmospheric Sciences, Indiana University Bloomington, 1001 E 10th St, Bloomington, IN, USA
- Department of Earth and Environmental Sciences, University of Michigan, 1100 N University Ave, Ann Arbor, MI 48109, USA
| | | | - Katrina E. Jones
- Department of Earth and Environmental Sciences, University of Manchester, M13 9PL Manchester, UK
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5
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Linden TJ, Burtner AE, Rickman J, McFeely A, Santana SE, Law CJ. Scaling patterns of body plans differ among squirrel ecotypes. PeerJ 2023; 11:e14800. [PMID: 36718452 PMCID: PMC9884040 DOI: 10.7717/peerj.14800] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/04/2023] [Indexed: 01/26/2023] Open
Abstract
Body size is often hypothesized to facilitate or constrain morphological diversity in the cranial, appendicular, and axial skeletons. However, how overall body shape scales with body size (i.e., body shape allometry) and whether these scaling patterns differ between ecological groups remains poorly investigated. Here, we test whether and how the relationships between body shape, body size, and limb lengths differ among species with different locomotor specializations, and describe the underlying morphological components that contribute to body shape evolution among squirrel (Sciuridae) ecotypes. We quantified the body size and shape of 87 squirrel species from osteological specimens held at museum collections. Using phylogenetic comparative methods, we first found that body shape and its underlying morphological components scale allometrically with body size, but these allometric patterns differ among squirrel ecotypes: chipmunks and gliding squirrels exhibited more elongate bodies with increasing body sizes whereas ground squirrels exhibited more robust bodies with increasing body size. Second, we found that only ground squirrels exhibit a relationship between forelimb length and body shape, where more elongate species exhibit relatively shorter forelimbs. Third, we found that the relative length of the ribs and elongation or shortening of the thoracic region contributes the most to body shape evolution across squirrels. Overall, our work contributes to the growing understanding of mammalian body shape evolution and how it is influenced by body size and locomotor ecology, in this case from robust subterranean to gracile gliding squirrels.
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Affiliation(s)
- Tate J. Linden
- University of Washington, Seattle, WA, United States of America
| | | | | | - Annika McFeely
- University of Washington, Seattle, WA, United States of America
| | | | - Chris J. Law
- University of Washington, Seattle, WA, United States of America,University of Texas at Austin, Austin, TX, United States of America,American Museum of Natural History, New York, NY, United States of America
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6
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Law CJ, Blackwell EA, Curtis AA, Dickinson E, Hartstone-Rose A, Santana SE. Decoupled evolution of the cranium and mandible in carnivoran mammals. Evolution 2022; 76:2959-2974. [PMID: 35875871 DOI: 10.1111/evo.14578] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 06/06/2022] [Accepted: 06/17/2022] [Indexed: 01/22/2023]
Abstract
The relationship between skull morphology and diet is a prime example of adaptive evolution. In mammals, the skull consists of the cranium and the mandible. Although the mandible is expected to evolve more directly in response to dietary changes, dietary regimes may have less influence on the cranium because additional sensory and brain-protection functions may impose constraints on its morphological evolution. Here, we tested this hypothesis by comparing the evolutionary patterns of cranium and mandible shape and size across 100+ species of carnivoran mammals with distinct feeding ecologies. Our results show decoupled modes of evolution in cranial and mandibular shape; cranial shape follows clade-based evolutionary shifts, whereas mandibular shape evolution is linked to broad dietary regimes. These results are consistent with previous hypotheses regarding hierarchical morphological evolution in carnivorans and greater evolutionary lability of the mandible with respect to diet. Furthermore, in hypercarnivores, the evolution of both cranial and mandibular size is associated with relative prey size. This demonstrates that dietary diversity can be loosely structured by craniomandibular size within some guilds. Our results suggest that mammal skull morphological evolution is shaped by mechanisms beyond dietary adaptation alone.
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Affiliation(s)
- Chris J Law
- Department of Integrative Biology, University of Texas, Austin, Texas, 78712.,Department of Biology, University of Washington, Seattle, Washington, 98105.,Burke Museum of Natural History and Culture, University of Washington, Seattle, Washington, 98105.,Richard Gilder Graduate School, American Museum of Natural History, New York, New York, 10024.,Department of Mammalogy, American Museum of Natural History, New York, New York, 10024.,Division of Paleontology, American Museum of Natural History, New York, New York, 10024
| | - Emily A Blackwell
- Richard Gilder Graduate School, American Museum of Natural History, New York, New York, 10024.,Department of Mammalogy, American Museum of Natural History, New York, New York, 10024.,Division of Paleontology, American Museum of Natural History, New York, New York, 10024.,Department of Biological Sciences, Smith College, Northampton, Massachusetts, 01063
| | - Abigail A Curtis
- Department of Biology, University of Washington, Seattle, Washington, 98105.,Burke Museum of Natural History and Culture, University of Washington, Seattle, Washington, 98105
| | - Edwin Dickinson
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, 27695.,Department of Anatomy, New York Institute of Technology College of Osteopathic Medicine, New York, New York, 11545
| | - Adam Hartstone-Rose
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, 27695
| | - Sharlene E Santana
- Department of Biology, University of Washington, Seattle, Washington, 98105.,Burke Museum of Natural History and Culture, University of Washington, Seattle, Washington, 98105
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7
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Hermanson G, Benson RBJ, Farina BM, Ferreira GS, Langer MC, Evers SW. Cranial ecomorphology of turtles and neck retraction as a possible trigger of ecological diversification. Evolution 2022; 76:2566-2586. [PMID: 36117268 PMCID: PMC9828723 DOI: 10.1111/evo.14629] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 08/24/2022] [Accepted: 08/29/2022] [Indexed: 01/22/2023]
Abstract
Turtles have a highly modified body plan, including a rigid shell that constrains postcranial anatomy. Skull morphology and neck mobility may therefore be key to ecological specialization in turtles. However, the ecological signal of turtle skull morphologies has not been rigorously evaluated, leaving uncertainties about the roles of ecological adaptation and convergence. We evaluate turtle cranial ecomorphology using three-dimensional geometric morphometrics and phylogenetic comparative methods. Skull shape correlates with allometry, neck retraction capability, and different aquatic feeding ecologies. We find that ecological variables influence skull shape only, whereas a key functional variable (the capacity for neck retraction) influences both shape and size. Ecology and functional predictions from three-dimensional shape are validated by high success rates for extant species, outperforming previous two-dimensional approaches. We use this to infer ecological and functional traits of extinct species. Neck retraction evolved among crownward stem-turtles by the Late Jurassic, signaling functional decoupling of the skull and neck from the shell, possibly linked to a major episode of ecomorphological diversification. We also find strong evidence for convergent ecological adaptations among marine groups. This includes parallel loss of neck retraction, evidence for active hunting, possible grazing, and suction feeding in extinct marine groups. Our large-scale assessment of dietary and functional adaptation throughout turtle evolution reveals the timing and origin of their distinct ecomorphologies, and highlights the potential for ecology and function to have distinct effects on skull form.
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Affiliation(s)
- Guilherme Hermanson
- Department of GeosciencesUniversity of FribourgFribourgCH‐1700Switzerland,Department of Earth SciencesUniversity of OxfordOxfordOX1 3ANUnited Kingdom,Laboratório de Paleontologia de Ribeirão PretoUniversidade de São PauloRibeirão Preto14040‐091Brazil
| | - Roger B. J. Benson
- Department of Earth SciencesUniversity of OxfordOxfordOX1 3ANUnited Kingdom
| | - Bruna M. Farina
- Laboratório de Paleontologia de Ribeirão PretoUniversidade de São PauloRibeirão Preto14040‐091Brazil,Department of BiologyUniversity of FribourgFribourgCH‐1700Switzerland
| | - Gabriel S. Ferreira
- Senckenberg Centre for Human Evolution and Palaeoenvironment (HEP)Eberhard Karls Universität Tübingen72076TübingenGermany,Fachbereich GeowissenschaftenUniversität Tübingen72074TübingenGermany
| | - Max C. Langer
- Laboratório de Paleontologia de Ribeirão PretoUniversidade de São PauloRibeirão Preto14040‐091Brazil
| | - Serjoscha W. Evers
- Department of GeosciencesUniversity of FribourgFribourgCH‐1700Switzerland
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8
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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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9
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Savvidou A, Youlatos D, Spassov N, Tamvakis A, Kostopoulos DS. Ecomorphology of the Early Pleistocene Badger Meles dimitrius from Greece. J MAMM EVOL 2022. [DOI: 10.1007/s10914-022-09609-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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10
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Law CJ. Different evolutionary pathways lead to incomplete convergence of elongate body shapes in carnivoran mammals. Syst Biol 2021; 71:788-796. [PMID: 34791502 DOI: 10.1093/sysbio/syab091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 11/01/2021] [Accepted: 11/09/2021] [Indexed: 11/13/2022] Open
Abstract
Although convergence is often recognized as a ubiquitous feature across the Tree of Life, whether the underlying traits also exhibit similar evolutionary pathways towards convergent forms puzzles biologists. In carnivoran mammals, "elongate," "slender," and "long" are often used to describe and even to categorize mustelids (martens, polecats, and weasels), herpestids (mongooses), viverrids (civets and genets), and other carnivorans together. But just how similar these carnivorans are and whether there is convergence in the morphological component that contribute to elongation has never been assessed. Here, I found that these qualitatively-described elongate carnivorans exhibited incomplete convergence towards elongate bodies compared to other terrestrial carnivorans. In contrast, the morphological components underlying body shape variation do not exhibit convergence despite evidence that these components are more elongate in elongate carnivorans compared to non-elongate carnivorans. Furthermore, these components also exhibited shorter but different phylogenetic half-lives towards more elongate adaptive peaks, indicating that different selective pressures can create multiple pathways to elongation. Incorporating the fossil record will facilitate further investigation of whether body elongation evolved adaptively or if it is simply a retained ancestral trait.
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Affiliation(s)
- Chris J Law
- Department of Biology, University of Washington, Seattle, WA, 98105; Richard Gilder Graduate School, Department of Mammalogy, and Division of Paleontology, American Museum of Natural History, New York, NY, USA 10024
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11
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Gálvez-López E, Kilbourne B, Cox PG. Cranial shape variation in mink: Separating two highly similar species. J Anat 2021; 240:210-225. [PMID: 34569054 PMCID: PMC8742963 DOI: 10.1111/joa.13554] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 09/08/2021] [Accepted: 09/09/2021] [Indexed: 01/09/2023] Open
Abstract
European and American minks (Mustela lutreola and Neovison vison, respectively) are very similar in their ecology, behavior, and morphology. However, the American mink is a generalist predator and seems to adapt better to anthropized environments, allowing it to outcompete the European mink in areas where it has been introduced, threatening the survival of the native species. To assess whether morphological differences may be contributing to the success of the American mink relative to the European mink, we analyzed shape variation in the cranium of both species using 3D geometric morphometrics. A set of 38 landmarks and 107 semilandmarks was used to study shape variation between and within species, and to assess how differences in size factored into that variation. Sexual dimorphism in both size and shape was also studied. Significant differences between species were found in cranial shape, but not in size. Relative to American mink, European mink have a shorter facial region with a rounder forehead and wider orbits, a longer neurocranium with less developed crests and processes, and an antero-medially placed tympanic bullae with an anteriorly expanded cranial border. Within species, size-related sexual dimorphism is highly significant, but sexual dimorphism in shape is only significant in American mink, not in European mink. Additionally, two trends common to both species were discovered, one related to allometric changes and another to sexual size dimorphism. Shape changes related to increasing size can be subdivided into two, probably related, groups: increased muscle force and growth. The first group somewhat parallels the differences between both mink species, while the second group of traits includes an anterodorsal expansion of the face, and the neurocranium shifting from a globous shape in small individuals to a dorsoventrally flattened ellipse in the largest ones. Finally, the sexual dimorphism trend, while also accounting for differences in muscle force, seems to be related to the observed dietary differences between males and females. Overall, differences between species and sexes, and shape changes with increasing size, seem to mainly relate to differences in masticatory-muscle volume and therefore muscle force and bite force, which, in turn, relate to a wider range of potential prey (bigger prey, tougher shells). Thus, muscle force (and dietary range) would be larger in American mink than in European mink, in males than in females, and in larger individuals than in smaller ones.
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Affiliation(s)
- Eloy Gálvez-López
- PalaeoHub, Department of Archaeology, University of York, York, United Kingdom
| | - Brandon Kilbourne
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
| | - Philip G Cox
- PalaeoHub, Department of Archaeology, University of York, York, United Kingdom
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12
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Melstrom KM, Angielczyk KD, Ritterbush KA, Irmis RB. The limits of convergence: the roles of phylogeny and dietary ecology in shaping non-avian amniote crania. ROYAL SOCIETY OPEN SCIENCE 2021; 8:202145. [PMID: 34540239 PMCID: PMC8441121 DOI: 10.1098/rsos.202145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 08/17/2021] [Indexed: 05/28/2023]
Abstract
Cranial morphology is remarkably varied in living amniotes and the diversity of shapes is thought to correspond with feeding ecology, a relationship repeatedly demonstrated at smaller phylogenetic scales, but one that remains untested across amniote phylogeny. Using a combination of morphometric methods, we investigate the links between phylogenetic relationships, diet and skull shape in an expansive dataset of extant toothed amniotes: mammals, lepidosaurs and crocodylians. We find that both phylogeny and dietary ecology have statistically significant effects on cranial shape. The three major clades largely partition morphospace with limited overlap. Dietary generalists often occupy clade-specific central regions of morphospace. Some parallel changes in cranial shape occur in clades with distinct evolutionary histories but similar diets. However, members of a given clade often present distinct cranial shape solutions for a given diet, and the vast majority of species retain the unique aspects of their ancestral skull plan, underscoring the limits of morphological convergence due to ecology in amniotes. These data demonstrate that certain cranial shapes may provide functional advantages suited to particular dietary ecologies, but accounting for both phylogenetic history and ecology can provide a more nuanced approach to inferring the ecology and functional morphology of cryptic or extinct amniotes.
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Affiliation(s)
- Keegan M. Melstrom
- Dinosaur Institute, Natural History Museum of Los Angeles County, 900 W Exposition Boulevard, Los Angeles, CA 90007, USA
- Department of Geology and Geophysics, University of Utah, 115 S 1460 E, Salt Lake City, UT 84112-0102, USA
- Natural History Museum of Utah, University of Utah, 301 Wakara Way, Salt Lake City, UT 84108-1214, USA
| | - Kenneth D. Angielczyk
- Negaunee Integrative Research Center, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605-2496, USA
| | - Kathleen A. Ritterbush
- Department of Geology and Geophysics, University of Utah, 115 S 1460 E, Salt Lake City, UT 84112-0102, USA
| | - Randall B. Irmis
- Department of Geology and Geophysics, University of Utah, 115 S 1460 E, Salt Lake City, UT 84112-0102, USA
- Natural History Museum of Utah, University of Utah, 301 Wakara Way, Salt Lake City, UT 84108-1214, USA
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13
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Hartstone-Rose A, Dickinson E, Deutsch AR, Worden N, Hirschkorn GA. Masticatory muscle architectural correlates of dietary diversity in Canidae, Ursidae, and across the order Carnivora. Anat Rec (Hoboken) 2021; 305:477-497. [PMID: 34449131 DOI: 10.1002/ar.24748] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/17/2021] [Accepted: 07/15/2021] [Indexed: 01/11/2023]
Abstract
Carnivorans represent extreme ecomorphological diversity, encompassing remarkable variation in form, habitat, and diet. The relationship between the masticatory musculature and dietary ecology has been explored in a number of carnivoran lineages, including felids and the superfamily Musteloidea. In this study, we present novel architectural data on two additional carnivoran families-Ursidae and Canidae-and supplement these previous studies with additional felid, musteloid, herpestid, hyaenid, and viverrid taxa (a total of 53 species across 10 families). Gross dissection data were collected following a standardized protocol-sharp dissection followed by chemical digestion. Summed jaw adductor forces were also transformed into bite force estimates (BF) using osteologically calculated leverages. All data were linearized, log-transformed, and size-adjusted using two proxies for each taxon-body mass (BM) and cranial geometric mean-to assess relative scaling trends. These architectural data were then analyzed in the context of dietary ecology to examine the impact of dietary size (DS) and dietary mechanical properties (DMP). Muscle mass, physiological cross-sectional area, and BF scaled with isometry or positive allometry in all cases, whereas fascicle lengths (FLs) scaled with isometry or negative allometry. With respect to diet, BM-adjusted FLs were strongly correlated with DS in musteloids, but not in any other lineage. The relationship between size-adjusted BF and DMP was also significant within musteloids, and across the sample as a whole, but not within other individual lineages. This interfamilial trend may reflect the increased morphological and dietary diversity of musteloids relative to other carnivoran groups.
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Affiliation(s)
- Adam Hartstone-Rose
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Edwin Dickinson
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Ashley R Deutsch
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Nikole Worden
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Gabrielle A Hirschkorn
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
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14
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Dickinson E, Davis JS, Deutsch AR, Patel D, Nijhawan A, Patel M, Blume A, Gannon JL, Turcotte CM, Walker CS, Hartstone-Rose A. Evaluating bony predictors of bite force across the order Carnivora. J Morphol 2021; 282:1499-1513. [PMID: 34313337 DOI: 10.1002/jmor.21400] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/30/2021] [Accepted: 07/18/2021] [Indexed: 12/28/2022]
Abstract
In carnivorans, bite force is a critical and ecologically informative variable that has been correlated with multiple morphological, behavioral, and environmental attributes. Whereas in vivo measures of biting performance are difficult to obtain in many taxa-and impossible in extinct species-numerous osteological proxies exist for estimating masticatory muscle size and force. These proxies include both volumetric approximations of muscle dimensions and direct measurements of muscular attachment sites. In this study, we compare three cranial osteological techniques for estimating muscle size (including 2D-photographic and 3D-surface data approaches) against dissection-derived muscle weights and physiological cross-sectional area (PCSA) within the jaw adductor musculature of 40 carnivoran taxa spanning eight families, four orders of magnitude in body size, and the full dietary spectrum of the order. Our results indicate that 3D-approaches provide more accurate estimates of muscle size than do surfaces measured from 2D-lateral photographs. However, estimates of a muscle's maximum cross-sectional area are more closely correlated with muscle mass and PCSA than any estimates derived from muscle attachment areas. These findings highlight the importance of accounting for muscle thickness in osteological estimations of the masticatory musculature; as muscles become volumetrically larger, their larger cross-sectional area does not appear to be associated with a proportional increase in the attachment site area. Though volumetric approaches approximate muscle dimensions well across the order as a whole, caution should be exercised when applying any single method as a predictor across diverse phylogenies.
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Affiliation(s)
- Edwin Dickinson
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Jillian S Davis
- Pathology, Anatomy, and Laboratory Medicine Department, West Virginia University School of Medicine, Morgantown, West Virginia, USA
| | - Ashley R Deutsch
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Dhuru Patel
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Akash Nijhawan
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Meet Patel
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Abby Blume
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Jordan L Gannon
- Biology Department, High Point University, High Point, North Carolina, USA
| | - Cassandra M Turcotte
- Department of Anthropology, New York University, New York, New York, USA.,New York Consortium in Evolutionary Primatology, New York, New York, USA
| | - Christopher S Walker
- Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - Adam Hartstone-Rose
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA
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15
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Siciliano‐Martina L, Light JE, Riley DG, Lawing AM. One of these wolves is not like the other: morphological effects and conservation implications of captivity in Mexican wolves. Anim Conserv 2021. [DOI: 10.1111/acv.12724] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- L. Siciliano‐Martina
- Interdisciplinary PhD Program in Ecology and Evolutionary Biology Texas A&M University College Station TX USA
- Department of Biology Texas State University San Marcos TX USA
| | - J. E. Light
- Interdisciplinary PhD Program in Ecology and Evolutionary Biology Texas A&M University College Station TX USA
- Department of Ecology and Conservation Biology Texas A&M University College Station TX USA
| | - D. G. Riley
- Department of Animal Science Texas A&M University College Station TX USA
| | - A. M. Lawing
- Interdisciplinary PhD Program in Ecology and Evolutionary Biology Texas A&M University College Station TX USA
- Department of Ecology and Conservation Biology Texas A&M University College Station TX USA
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16
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Bates KT, Wang L, Dempsey M, Broyde S, Fagan MJ, Cox PG. Back to the bones: do muscle area assessment techniques predict functional evolution across a macroevolutionary radiation? J R Soc Interface 2021; 18:20210324. [PMID: 34283941 PMCID: PMC8292018 DOI: 10.1098/rsif.2021.0324] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Measures of attachment or accommodation area on the skeleton are a popular means of rapidly generating estimates of muscle proportions and functional performance for use in large-scale macroevolutionary studies. Herein, we provide the first evaluation of the accuracy of these muscle area assessment (MAA) techniques for estimating muscle proportions, force outputs and bone loading in a comparative macroevolutionary context using the rodent masticatory system as a case study. We find that MAA approaches perform poorly, yielding large absolute errors in muscle properties, bite force and particularly bone stress. Perhaps more fundamentally, these methods regularly fail to correctly capture many qualitative differences between rodent morphotypes, particularly in stress patterns in finite-element models. Our findings cast doubts on the validity of these approaches as means to provide input data for biomechanical models applied to understand functional transitions in the fossil record, and perhaps even in taxon-rich statistical models that examine broad-scale macroevolutionary patterns. We suggest that future work should go back to the bones to test if correlations between attachment area and muscle size within homologous muscles across a large number of species yield strong predictive relationships that could be used to deliver more accurate predictions for macroevolutionary and functional studies.
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Affiliation(s)
- Karl T Bates
- Department of Musculoskeletal Biology, Institute of Life Course and Medical Sciences, University of Liverpool, The William Henry Duncan Building, 6 West Derby Street, Liverpool L7 8TX, UK
| | - Linjie Wang
- Department of Engineering, University of Hull, Hull HU6 7RX, UK
| | - Matthew Dempsey
- Department of Musculoskeletal Biology, Institute of Life Course and Medical Sciences, University of Liverpool, The William Henry Duncan Building, 6 West Derby Street, Liverpool L7 8TX, UK
| | - Sarah Broyde
- Department of Musculoskeletal Biology, Institute of Life Course and Medical Sciences, University of Liverpool, The William Henry Duncan Building, 6 West Derby Street, Liverpool L7 8TX, UK
| | - Michael J Fagan
- Department of Engineering, University of Hull, Hull HU6 7RX, UK
| | - Philip G Cox
- Department of Archaeology, University of York, PalaeoHub, Wentworth Way, Heslington, York YO10 5DD, UK.,Hull York Medical School, University of York, Heslington, York YO10 5DD, UK
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17
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Abstract
AbstractMorphological diversity is often attributed as adaptations to distinct ecologies. Although biologists have long hypothesized that distinct ecologies drive the evolution of body shape, these relationships are rarely tested across macroevolutionary scales in mammals. Here, I tested hypotheses that locomotor, hunting, and dietary ecologies influenced body shape evolution in carnivorans, a morphologically and ecologically diverse clade of mammals. I found that adaptive models with ecological trait regimes were poor predictors of carnivoran body shape and the underlying morphological components that contribute to body shape variation. Instead, the best-supported model exhibited clade-based evolutionary shifts, indicating that the complexity and variation of body shape landscape cannot be effectively captured by a priori ecological regimes. However, ecological adaptations of body shapes cannot be ruled out, as aquatic and terrestrial carnivorans exhibited opposite allometric patterns of body shape that may be driven by different gravitational constraints associated with these different environments. Similar to body size, body shape is a prominent feature of vertebrate morphology that may transcend one-to-one mapping relationships between morphology and ecological traits, enabling species with distinct body shapes to exploit similar resources and exhibit similar ecologies. Together, these results demonstrate that the multidimensionality of both body shape morphology and ecology makes it difficult to disentangle the complex relationship among morphological evolution, ecological diversity, and phylogeny across macroevolutionary scales.
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18
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Tse YT, Calede JJM. Quantifying the link between craniodental morphology and diet in the Soricidae using geometric morphometrics. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab005] [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]
Abstract
Abstract
Dietary adaptations have often been associated with heightened taxonomic diversity. Yet, one of the most species-rich mammalian families, the Soricidae, is often considered to be ecologically and morphologically relatively homogenous. Here, we use geometric morphometrics to capture skull and dentary morphology in a broad sample of shrew species and test the hypothesis that morphological variation among shrew species reflects adaptations to food hardness. Our analyses demonstrate that morphology is associated with dietary ecology. Species that consume hard food items are larger and have specific morphological adaptions including an anteroposteriorly expanded parietal, an anteroposteriorly short and dorsoventrally tall rostrum, a mediolaterally wide palate, buccolingually wide cheek teeth, a large coronoid process and a dorsoventrally short jaw joint. The masseter muscle does not appear to play an important role in the strong bite force of shrews and the dentary is a better indicator of ecology than the skull. Our phylogenetic flexible discriminant function analysis suggests that the evolutionary history of shrews has shaped their morphology, canalizing dietary adaptations and enabling functional equivalence whereby different morphologies achieve similar dietary performances. Our work makes possible future studies of niche partitioning among sympatric species as well as the investigation of the diet of extinct soricids.
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Affiliation(s)
- Yuen Ting Tse
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, Ohio, OH, USA
| | - Jonathan J M Calede
- Department of Evolution, Ecology, and Organismal Biology, The Ohio State University, Columbus, Ohio, OH, USA
- The Ohio State University at Marion, Marion, Ohio, OH, USA
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19
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Siciliano-Martina L, Light JE, Lawing AM. Cranial morphology of captive mammals: a meta-analysis. Front Zool 2021; 18:4. [PMID: 33485360 PMCID: PMC7825229 DOI: 10.1186/s12983-021-00386-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 01/14/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Captive facilities such as zoos are uniquely instrumental in conservation efforts. To fulfill their potential as bastions for conservation, zoos must preserve captive populations as appropriate proxies for their wild conspecifics; doing so will help to promote successful reintroduction efforts. Morphological changes within captive populations may be detrimental to the fitness of individual animals because these changes can influence functionality; thus, it is imperative to understand the breadth and depth of morphological changes occurring in captive populations. Here, we conduct a meta-analysis of scientific literature reporting comparisons of cranial measures between captive and wild populations of mammals. We investigate the pervasiveness of cranial differences and whether cranial morphological changes are associated with ecological covariates specific to individual species, such as trophic level, dietary breadth, and home range size. RESULTS Cranial measures of skull length, skull width, and the ratio of skull length-to-width differed significantly between many captive and wild populations of mammals reported in the literature. Roughly half of captive populations differed from wild populations in at least one cranial measure, although the degree of changes varied. Carnivorous species with a limited dietary breadth displayed the most consistent changes associated with skull widening. Species with a more generalized diet displayed less morphological changes in captivity. CONCLUSIONS Wild and captive populations of mammals differed in cranial morphology, but the nature and magnitude of their cranial differences varied considerably across taxa. Although changes in cranial morphology occur in captivity, specific changes cannot be generalized for all captive mammal populations. The nature of cranial changes in captivity may be specific to particular taxonomic groups; thus, it may be possible to establish expectations across smaller taxonomic units, or even disparate groups that utilize their cranial morphology in a similar way. Given that morphological changes occurring in captive environments like zoos have the potential to limit reintroduction success, our results call for a critical evaluation of current captive husbandry practices to prevent unnecessary morphological changes.
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Affiliation(s)
- Leila Siciliano-Martina
- Interdisciplinary Program in Ecology & Evolutionary Biology, Texas A&M University, College Station, TX, 77843, USA.
- Department of Biology, Texas State University, San Marcos, TX, 78666, USA.
| | - Jessica E Light
- Interdisciplinary Program in Ecology & Evolutionary Biology, Texas A&M University, College Station, TX, 77843, USA
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX, 77843, USA
| | - A Michelle Lawing
- Interdisciplinary Program in Ecology & Evolutionary Biology, Texas A&M University, College Station, TX, 77843, USA
- Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX, 77843, USA
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20
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Law CJ. Evolutionary and morphological patterns underlying carnivoran body shape diversity. Evolution 2020; 75:365-375. [PMID: 33314085 DOI: 10.1111/evo.14143] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 11/13/2020] [Accepted: 11/22/2020] [Indexed: 12/15/2022]
Abstract
The diversity of body shapes is one of the most prominent features of phenotypic variation in vertebrates. Biologists, however, still lack a full understanding of the underlying morphological components that contribute to its diversity, particularly in endothermic vertebrates such as mammals. In this study, hypotheses pertaining to the evolution of the cranial and axial components that contribute to the diversity of carnivoran body shapes were tested. Three trends were found in the evolution of carnivoran body shapes: (1) carnivorans exhibit diverse body shapes with intrafamilial variation predicted best by family clade age, (2) body shape is driven by strong allometric effects of body size where species become more elongate with decreasing size, and (3) the thoracic and lumbar regions and rib length contribute the most to body shape variation, albeit pathways differ between different families. These results reveal the morphological patterns that led to increased diversity in carnivoran body shapes and elucidate the similarities and dissimilarities that govern body shape diversity across vertebrates.
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Affiliation(s)
- Chris J Law
- Department of Mammalogy and Division of Paleontology, American Museum of Natural History, 200 Central Park West, New York, NY, 10024.,Department of Biology, University of Washington, Seattle, WA, 98105
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21
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de Barros FC, Grizante MB, Zampieri FAM, Kohlsdorf T. Peculiar relationships among morphology, burrowing performance and sand type in two fossorial microteiid lizards. ZOOLOGY 2020; 144:125880. [PMID: 33310388 DOI: 10.1016/j.zool.2020.125880] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 12/16/2022]
Abstract
Associations among ecology, morphology and locomotor performance have been intensively investigated in several vertebrate lineages. Knowledge on how phenotypes evolve in natural environments likely benefits from identification of circumstances that might expand current ecomorphological equations. In this study, we used two species of Calyptommatus lizards from Brazilian Caatingas to evaluate if specific soil properties favor burrowing performance. As a derived prediction, we expected that functional associations would be easily detectable at the sand condition that favors low-resistance burrowing. We collected two endemic lizards and soil samples in their respective localities, obtained morphological data and recorded performance of both species in different sand types. As a result, the two species burrowed faster at the fine and homogeneous sand, the only condition where we detected functional associations between morphology and locomotion. In this sand type, lizards from both Calyptommatus species that have higher trunks and more concave heads were the ones that burrowed faster, and these phenotypic traits did not morphologically discriminate the two Calyptommatus populations studied. We discuss that integrative approaches comprising manipulation of environmental conditions clearly contribute to elucidate processes underlying phenotypic evolution in fossorial lineages.
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Affiliation(s)
- Fábio C de Barros
- Department of Biology, FFCLRP, University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, SP, 14040-901, Brazil; Department of Ecology and Evolutionary Biology, ICAQF, Federal University of São Paulo, Rua Prof. Artur Riedel, 275, Diadema, SP, 09972-270, Brazil.
| | - Mariana B Grizante
- Department of Biology, FFCLRP, University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, SP, 14040-901, Brazil; Instituto Dante Pazzanese de Cardiologia, Brazil
| | - Felipe A M Zampieri
- Department of Biology, FFCLRP, University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, SP, 14040-901, Brazil
| | - Tiana Kohlsdorf
- Department of Biology, FFCLRP, University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, SP, 14040-901, Brazil.
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22
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Migliorini RP, Fornel R, Kasper CB. Geographic variation in the skull morphology of the lesser grison ( Galictis cuja: Carnivora, Mustelidae) from two Brazilian ecoregions. PeerJ 2020; 8:e9388. [PMID: 33194321 PMCID: PMC7648447 DOI: 10.7717/peerj.9388] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 05/28/2020] [Indexed: 11/20/2022] Open
Abstract
Background The lesser grison (Galictis cuja) is one of the least known carnivores in the Neotropical region. Its wide geographical occurrence and range of habitats could lead to morphological variations along its distribution. So, this study aimed to investigate the variation in skull shape and size of this species, by testing the existence of ecotypes adapted to their respective environments (Uruguayan savanna and Atlantic Forest), as well as its relationship with selected abiotic variables. Methods The skulls of 52 museum specimens were photographed in the ventral, dorsal, and lateral views, and were analyzed using geometric morphometric techniques. Results We found sexual size dimorphism, with males being larger than females. The shape variation between sexes, as well as between ecoregions, is mostly explained by the effect of allometry. The specimens from Uruguayan savanna are larger than the ones from the Atlantic Forest. Size variation was also significantly correlated to latitude, temperature and precipitation patterns. No correlation between skull shape with geographical distance was detected. Discussion Morphometric measurements and diet data of lesser grison in regions from higher latitudes than our sampling show a tendency to heavier individuals, and the consumption of bigger prey compared to Uruguayan savanna. The results indicated the smaller specimens associated to low variability in annual temperature, congruent to Atlantic Forest region. An explanation for observed variation may be related to the “resource rule” but, due the minimal natural history information regards this species, we can just speculate about this.
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Affiliation(s)
- Raissa Prior Migliorini
- Laboratório de Biologia de Mamíferos e Aves (LABIMAVE), Programa de Pós Graduação em Ciências Biológicas (PPGCB), Universidade Federal do Pampa (UNIPAMPA), São Gabriel, Brazil
| | - Rodrigo Fornel
- Departamento de Ciências Biológicas, Universidade Regional Integrada do Alto Uruguai e das Missões (URI), Erechim, Brazil
| | - Carlos Benhur Kasper
- Laboratório de Biologia de Mamíferos e Aves (LABIMAVE), Programa de Pós Graduação em Ciências Biológicas (PPGCB), Universidade Federal do Pampa (UNIPAMPA), São Gabriel, Brazil
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23
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Law CJ. Sex-specific ontogenetic patterns of cranial morphology, theoretical bite force, and underlying jaw musculature in fishers and American martens. J Anat 2020; 237:727-740. [PMID: 32519772 DOI: 10.1111/joa.13231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/09/2020] [Accepted: 05/11/2020] [Indexed: 11/30/2022] Open
Abstract
The carnivoran cranium undergoes tremendous growth in size and development of shape to process prey as adults and, importantly, these ontogenetic processes can also differ between the sexes. How these ontogenetic changes in morphology actually relate to the underlying jaw musculature and overall bite performance has rarely been investigated. In this study, I examined sex-specific ontogenetic changes in cranial morphology, jaw adductor muscles, and theoretical bite force between subadults and adults in the fisher (Pekania pennanti) and American marten (Martes americana). I found evidence that cranial size alone does not completely explain ontogenetic increases in bite forces as found in other mammalian species. Instead, cranial shape development also drives ontogenetic increases in relative bite force by broadening the zygomatic arches and enlargement of the sagittal crest, both of which enable relatively larger jaw adductor muscles to attach. In contrast, examination of sexual dimorphism within each age-class revealed that cranial shape dimorphism did not translate to dimorphism in either size-corrected bite forces or size-corrected physiological cross-sectional area of the jaw adductor muscles. These results reveal that morphological size and shape variation can have different influences on bite performance depending on the level of intraspecific variation that is examined (i.e. ontogenetic versus sexual dimorphism).
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Affiliation(s)
- Chris J Law
- Department of Mammalogy and Division of Paleontology, American Museum of Natural History, New York, NY, USA
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24
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Barbero S, Teta P, Cassini GH. An Ecomorphological Comparative Study of Extant and Late Holocene Sigmodontinae (Rodentia, Cricetidae) Assemblages from Central-Eastern Argentina. J MAMM EVOL 2020. [DOI: 10.1007/s10914-020-09497-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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25
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Jones TM, Benson TJ, Ward MP. Does the size and developmental stage of traits at fledging reflect juvenile flight ability among songbirds? Funct Ecol 2020. [DOI: 10.1111/1365-2435.13513] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Todd M. Jones
- Department of Natural Resources and Environmental Sciences University of Illinois at Urbana‐Champaign Urbana IL USA
- Illinois Natural History Survey Prairie Research Institute University of Illinois at Urbana‐Champaign Champaign IL USA
| | - Thomas J. Benson
- Department of Natural Resources and Environmental Sciences University of Illinois at Urbana‐Champaign Urbana IL USA
- Illinois Natural History Survey Prairie Research Institute University of Illinois at Urbana‐Champaign Champaign IL USA
| | - Michael P. Ward
- Department of Natural Resources and Environmental Sciences University of Illinois at Urbana‐Champaign Urbana IL USA
- Illinois Natural History Survey Prairie Research Institute University of Illinois at Urbana‐Champaign Champaign IL USA
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26
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Form, Function and Evolution of the Skull of Didelphid Marsupials (Didelphimorphia: Didelphidae). J MAMM EVOL 2020. [DOI: 10.1007/s10914-019-09495-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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27
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Solitary meat-eaters: solitary, carnivorous carnivorans exhibit the highest degree of sexual size dimorphism. Sci Rep 2019; 9:15344. [PMID: 31653949 PMCID: PMC6814822 DOI: 10.1038/s41598-019-51943-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 10/09/2019] [Indexed: 12/15/2022] Open
Abstract
Although sexual size dimorphism (SSD) is widespread across the animal tree of life, the underlying evolutionary processes that influence this phenomenon remains elusive and difficult to tease apart. In this study, I examined how social system (as a proxy for sexual selection) and diet (as a proxy for natural selection) influenced the evolution of SSD in terrestrial carnivorans (Carnivora; Mammalia). Using phylogenetic comparative methods, I found that are territorial solitary and carnivorous carnivorans exhibited selection towards increased degree of male-biased SSD compared to other carnivorans with alternative social systems and diets. I also found the absence of Rensch’s rule across most carnivoran clades, suggestion a relaxation of the influences of sexual selection on SSD. These results together suggest that sexual selection and niche divergence together are important processes influencing the evolution of male-biased SSD in extant terrestrial carnivorans.
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Law CJ, Mehta RS. Dry versus wet and gross: Comparisons between the dry skull method and gross dissection in estimations of jaw muscle cross-sectional area and bite forces in sea otters. J Morphol 2019; 280:1706-1713. [PMID: 31513299 DOI: 10.1002/jmor.21061] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 07/24/2019] [Accepted: 08/13/2019] [Indexed: 02/05/2023]
Abstract
Bite force is a measure of feeding performance used to elucidate links between animal morphology, ecology, and fitness. Obtaining live individuals for in vivo bite-force measurements or freshly deceased specimens for bite force modeling is challenging for many species. Thomason's dry skull method for mammals relies solely on osteological specimens and, therefore, presents an advantageous approach that enables researchers to estimate and compare bite forces across extant and even extinct species. However, how accurately the dry skull method estimates physiological cross-sectional area (PCSA) of the jaw adductor muscles and theoretical bite force has rarely been tested. Here, we use an ontogenetic series of southern sea otters (Enhydra lutris nereis) to test the hypothesis that skeletomuscular traits estimated from the dry skull method accurately predicts test traits derived from dissection-based biomechanical modeling. Although variables from these two methods exhibited strong positive relationships across ontogeny, we found that the dry skull method overestimates PCSA of the masseter and underestimates PCSA of the temporalis. Jaw adductor in-levers for both jaw muscles and overall bite force are overestimated. Surprisingly, we reveal that sexual dimorphism in craniomandibular shape affects temporalis PCSA estimations; the dry skull method predicted female temporalis PCSA well but underestimates male temporalis PCSA across ontogeny. These results highlight the importance of accounting for sexual dimorphism and other intraspecific variation when using the dry skull method. Together, we found the dry skull method provides an underestimation of bite force over ontogeny and that the underlying anatomical components driving bite force may be misrepresented.
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Affiliation(s)
- Chris J Law
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California
| | - Rita S Mehta
- Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California
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Hartstone‐Rose A, Hertzig I, Dickinson E. Bite Force and Masticatory Muscle Architecture Adaptations in the Dietarily Diverse Musteloidea (Carnivora). Anat Rec (Hoboken) 2019; 302:2287-2299. [DOI: 10.1002/ar.24233] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/03/2019] [Accepted: 07/03/2019] [Indexed: 01/09/2023]
Affiliation(s)
- Adam Hartstone‐Rose
- Department of Biological Sciences North Carolina State University Raleigh North Carolina
| | - Isabella Hertzig
- Department of Biological Sciences North Carolina State University Raleigh North Carolina
| | - Edwin Dickinson
- Department of Biological Sciences North Carolina State University Raleigh North Carolina
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Law CJ. Evolutionary shifts in extant mustelid (Mustelidae: Carnivora) cranial shape, body size and body shape coincide with the Mid-Miocene Climate Transition. Biol Lett 2019; 15:20190155. [PMID: 31138097 DOI: 10.1098/rsbl.2019.0155] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Environmental changes can lead to evolutionary shifts in phenotypic traits, which in turn facilitate the exploitation of novel adaptive landscapes and lineage diversification. The global cooling, increased aridity and expansion of open grasslands during the past 50 Myr are prime examples of new adaptive landscapes that spurred lineage and ecomorphological diversity of several mammalian lineages such as rodents and large herbivorous megafauna. However, whether these environmental changes facilitated evolutionary shifts in small- to mid-sized predator morphology is unknown. Here, I used a complete cranial and body morphological dataset to examine the timing of evolutionary shifts in cranial shape, body size and body shape within extant mustelids (martens, otters, polecats and weasels) during the climatic and environmental changes of the Cenozoic. I found that evolutionary shifts in all three traits occurred within extant mustelid subclades just after the onset of the Mid-Miocene Climate Transition. These mustelid subclades first shifted towards more elongate body plans followed by concurrent shifts towards smaller body sizes and more robust crania. I hypothesize that these cranial and body morphological shifts enabled mustelids to exploit novel adaptive zones associated with the climatic and environmental changes of the Mid to Late Miocene, which facilitated significant increases in clade carrying capacity.
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Affiliation(s)
- Chris J Law
- Ecology and Evolutionary Biology, University of California Santa Cruz , 130 McAllister Way, Santa Cruz, CA 95060 , USA
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