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McClain CR, Webb TJ, Heim NA, Knope ML, Monarrez PM, Payne JL. Navigating uncertainty in maximum body size in marine metazoans. Ecol Evol 2024; 14:e11506. [PMID: 38840585 PMCID: PMC11151150 DOI: 10.1002/ece3.11506] [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: 12/29/2023] [Revised: 05/15/2024] [Accepted: 05/20/2024] [Indexed: 06/07/2024] Open
Abstract
Body size is a fundamental biological trait shaping ecological interactions, evolutionary processes, and our understanding of the structure and dynamics of marine communities on a global scale. Accurately defining a species' body size, despite the ease of measurement, poses significant challenges due to varied methodologies, tool usage, and subjectivity among researchers, resulting in multiple, often discrepant size estimates. These discrepancies, stemming from diverse measurement approaches and inherent variability, could substantially impact the reliability and precision of ecological and evolutionary studies reliant on body size data across extensive species datasets. This study examines the variation in reported maximum body sizes across 69,570 individual measurements of maximum size, ranging from <0.2 μm to >45 m, for 27,271 species of marine metazoans. The research aims to investigate how reported maximum size variations within species relate to organism size, taxonomy, habitat, and the presence of skeletal structures. The investigation particularly focuses on understanding why discrepancies in maximum size estimates arise and their potential implications for broader ecological and evolutionary studies relying on body size data. Variation in reported maximum sizes is zero for 38% of species, and low for most species, although it exceeds two orders of magnitude for some species. The likelihood of zero variation in maximum size decreased with more measurements and increased in larger species, though this varied across phyla and habitats. Pelagic organisms consistently had low maximum size range values, while small species with unspecified habitats had the highest variation. Variations in maximum size within a species were notably smaller than interspecific variation at higher taxonomic levels. Significant variation in maximum size estimates exists within marine species, and partially explained by organism size, taxonomic group, and habitat. Variation in maximum size could be reduced by standardized measurement protocols and improved meta-data. Despite the variation, egregious errors in published maximum size measurements are rare, and their impact on comparative macroecological and macroevolutionary research is likely minimal.
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Affiliation(s)
- Craig R. McClain
- Department of BiologyUniversity of Louisiana at LafayetteLafayetteLouisianaUSA
| | - Thomas J. Webb
- Ecology & Evolutionary Biology, School of BiosciencesUniversity of SheffieldSheffieldUK
| | - Noel A. Heim
- Department of Earth and Climate SciencesTufts UniversityMedfordMassachusettsUSA
| | | | - Pedro M. Monarrez
- Department of Earth and Planetary SciencesStanford UniversityStanfordCaliforniaUSA
- Department of Earth, Planetary, and Space SciencesUniversity of California, Los AngelesLos AngelesCaliforniaUSA
| | - Jonathan L. Payne
- Department of Earth and Planetary SciencesStanford UniversityStanfordCaliforniaUSA
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2
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Fernandez Blanco MV, Cassini GH, Bona P. A three-dimensional geometric morphometric analysis of the morphological transformation of Caiman lower jaw during post-hatching ontogeny. PeerJ 2023; 11:e15548. [PMID: 37456902 PMCID: PMC10349558 DOI: 10.7717/peerj.15548] [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: 02/02/2023] [Accepted: 05/22/2023] [Indexed: 07/18/2023] Open
Abstract
Shape ontogenetic changes of the lower jaw in crocodylians are poorly understood. In order to answer some questions related to the inter- and intraspecific morphological variation of the mandible of two extant Caiman species, we performed a three-dimensional geometric morphometric approach. For this purpose, we used landmarks and semilandmarks on two ontogenetic mandibular series of 48 and 15 post-hatching specimens of C. yacare and C. latirostris, respectively. We have also examined the relationship between these anatomical transformations and ontogenetic shifts in diet. We performed a principal component analysis (PCA) for the two species, and regression and partial least squares (PLS) analyses for each species, separately. As a result, species were segregated along the PC1 with specimens of C. yacare showing more gracile mandibles, and specimens of C. latirostris more robust ones. The PC2 and regression analyses showed an age gradient and represented ontogenetic shape changes. Adult caiman mandibles are higher and wider than juvenile ones, and shape changes are more conspicuous in C. latirostris. The PLS analyses showed a significant relationship between shape and diet. Morphological changes of the PLS1 of block-1 match with those of the regression analysis for both species. We have detected morphological transformations in areas where the musculature in charge of mandibular movements is attached. Common morphological changes occurring during ontogeny seem to reflect the same mechanical properties required for crushing and killing in both species, driven by an ontogenetic shift in the diet from invertebrates to vertebrates. Additionally, interspecific differences were also found to be correlated to ontogenetic changes in diet and could be related to dissimilar feeding mechanical requirements (e.g., stiffness and toughness of the item consumed), and to different habitat preferences. Robust mandibles would be more suitable for shallow and fully vegetated environments, as it can be seen in C. latirostris, whereas slender jaws seem to be more suitable for more aquatic species such as C. yacare.
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Affiliation(s)
- María Victoria Fernandez Blanco
- División Paleontología Vertebrados, Museo de La Plata, Unidades de Investigación Anexo II Museo, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Guillermo Hernán Cassini
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
- División Mastozoología, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Ciudad Autónoma de Buenos Aires, Argentina
- Departamento de Ciencias Básicas, Universidad Nacional de Luján, Luján, Buenos Aires, Argentina
| | - Paula Bona
- División Paleontología Vertebrados, Museo de La Plata, Unidades de Investigación Anexo II Museo, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
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3
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Farina BM, Godoy PL, Benson RBJ, Langer MC, Ferreira GS. Turtle body size evolution is determined by lineage-specific specializations rather than global trends. Ecol Evol 2023; 13:e10201. [PMID: 37384241 PMCID: PMC10293707 DOI: 10.1002/ece3.10201] [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: 01/24/2023] [Revised: 05/26/2023] [Accepted: 06/01/2023] [Indexed: 06/30/2023] Open
Abstract
Organisms display a considerable variety of body sizes and shapes, and macroevolutionary investigations help to understand the evolutionary dynamics behind such variations. Turtles (Testudinata) show great body size disparity, especially when their rich fossil record is accounted for. We explored body size evolution in turtles, testing which factors might influence the observed patterns and evaluating the existence of long-term directional trends. We constructed the most comprehensive body size dataset for the group to date, tested for correlation with paleotemperature, estimated ancestral body sizes, and performed macroevolutionary model-fitting analyses. We found no evidence for directional body size evolution, even when using very flexible models, thereby rejecting the occurrence of Cope's rule. We also found no significant effect of paleotemperature on overall through-time body size patterns. In contrast, we found a significant influence of habitat preference on turtle body size. Freshwater turtles display a rather homogeneous body size distribution through time. In contrast, terrestrial and marine turtles show more pronounced variation, with terrestrial forms being restricted to larger body sizes, up to the origin of testudinids in the Cenozoic, and marine turtles undergoing a reduction in body size disparity after the extinctions of many groups in the mid-Cenozoic. Our results, therefore, suggest that long-term, generalized patterns are probably explained by factors specific to certain groups and related at least partly to habitat use.
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Affiliation(s)
- Bruna M. Farina
- Department of BiologyUniversity of FribourgFribourgSwitzerland
- Swiss Institute of BioinformaticsFribourgSwitzerland
- Laboratório de Paleontologia de Ribeirão PretoUniversidade de São PauloRibeirão PretoBrazil
| | - Pedro L. Godoy
- Laboratório de Paleontologia de Ribeirão PretoUniversidade de São PauloRibeirão PretoBrazil
- Department of Anatomical SciencesStony Brook UniversityStony BrookNew YorkUSA
| | - Roger B. J. Benson
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNew YorkUSA
| | - Max C. Langer
- Laboratório de Paleontologia de Ribeirão PretoUniversidade de São PauloRibeirão PretoBrazil
| | - Gabriel S. Ferreira
- Senckenberg Centre for Human Evolution and Palaeoenvironment (HEP)Eberhard Karls Universität TübingenTübingenGermany
- Fachbereich GeowissenschaftenEberhard Karls Universität TübingenTübingenGermany
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4
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Lessner EJ, Dollman KN, Clark JM, Xu X, Holliday CM. Ecomorphological patterns in trigeminal canal branching among sauropsids reveal sensory shift in suchians. J Anat 2023; 242:927-952. [PMID: 36680380 PMCID: PMC10093182 DOI: 10.1111/joa.13826] [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: 06/13/2022] [Revised: 01/03/2023] [Accepted: 01/03/2023] [Indexed: 01/22/2023] Open
Abstract
The vertebrate trigeminal nerve is the primary mediator of somatosensory information from nerve endings across the face, extending nerve branches through bony canals in the face and mandibles, terminating in sensory receptors. Reptiles evolved several extreme forms of cranial somatosensation in which enhanced trigeminal tissues are present in species engaging in unique mechanosensory behaviors. However, morphology varies by clade and ecology among reptiles. Few lineages approach the extreme degree of tactile somatosensation possessed by crocodylians, the only remaining members of a clade that underwent an ecological transition from the terrestrial to semiaquatic habitat, also evolving a specialized trigeminal system. It remains to be understood how trigeminal osteological correlates inform how adaptations for enhanced cranial sensation evolved in crocodylians. Here we identify an increase in sensory abilities in Early Jurassic crocodylomorphs, preceding the transitions to a semiaquatic habitat. Through quantification of trigeminal neurovascular canal branching patterns in an extant phylogenetic bracket we quantify and identify morphologies associated with sensory behaviors in representative fossil taxa, we find stepwise progression of increasing neurovascular canal density, complexity, and distribution from the primitive archosaurian to the derived crocodilian condition. Model-based inferences of sensory ecologies tested on quantified morphologies of extant taxa with known sensory behaviors indicate a parallel increase in sensory abilities among pseudosuchians. These findings establish patterns of reptile trigeminal ecomorphology, revealing evolutionary patterns of somatosensory ecology.
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Affiliation(s)
- Emily J Lessner
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri, USA
| | | | - James M Clark
- Department of Biological Sciences, George Washington University, Washington, District of Columbia, USA
| | - Xing Xu
- Centre for Vertebrate Evolutionary Biology, Yunnan University, Kunming, China.,Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| | - Casey M Holliday
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri, USA
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5
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Acevedo AA, Palma RE, Olalla-Tárraga MÁ. Ecological and evolutionary trends of body size in Pristimantis frogs, the world's most diverse vertebrate genus. Sci Rep 2022; 12:18106. [PMID: 36302809 PMCID: PMC9613995 DOI: 10.1038/s41598-022-22181-5] [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: 03/17/2022] [Accepted: 10/11/2022] [Indexed: 12/30/2022] Open
Abstract
Body size is a key organismal trait. However, the environmental and evolutionary factors that drive body size patterns at the interspecific level remain unclear. Here, we explored these relationships between phenotype-environment using neotropical frogs of Pristimantis, the world's most diverse vertebrate genus. We analyzed: (a) whether this group follows the Rensch's rule, a trend of sexual size dimorphism (SSD) to increase with size when males are the larger sex; (b) whether environmental constraints have influenced body size variation; and (c) how the rates of body size evolution have varied over time. Analyses were based on two information sources, the first one including body sizes of ~ 85% (495 species) of known species in the genus, and a second one incorporating molecular phylogenetic information for 257 species. Our results showed that all Pristimantis species exhibited marked SSD but did not follow Rensch's rule. We found that the models that best explained body size in males, females, and SSD contained environmental variations in temperature, precipitation, and elevation as predictors. In turn, body size has evolved toward an optimum, with a decelerating rate of evolution differentiated between the large Pristimantis clades.
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Affiliation(s)
- Aldemar A. Acevedo
- grid.7870.80000 0001 2157 0406Laboratory of Evolutionary Biology, Department of Ecology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile ,grid.443909.30000 0004 0385 4466Laboratory of Genetics and Evolution, Department of Ecological Sciences, Faculty of Sciences, Universidad de Chile, Santiago, Chile ,grid.441950.d0000 0001 2107 1033Grupo de Investigación en Ecología y Biogeografía, Universidad de Pamplona, Pamplona, Colombia
| | - R. Eduardo Palma
- grid.7870.80000 0001 2157 0406Laboratory of Evolutionary Biology, Department of Ecology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Miguel Ángel Olalla-Tárraga
- grid.28479.300000 0001 2206 5938Department of Biology and Geology, Physics & Inorganic Chemistry, Universidad Rey Juan Carlos, Móstoles, Spain
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6
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Wu H, Gao S, Xia L, Li P. Evolutionary rates of body-size-related genes and ecological factors involved in driving body size evolution of squamates. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.1007409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Body size is one of the most important traits of an organism. Among reptiles, both lizards and snakes show body size differences that span a similar six orders of magnitude variation. However, the molecular mechanisms underlying body size variation in squamates remain obscure. Here, we performed comparative genomic analyses of 101 body-size-related genes from 28 reptilian genomes. Phylogenetic analysis by maximum likelihood (PAML) revealed that snakes showed higher evolutionary rates in body-size-related genes, and had an almost two-fold increase in the number of positively selected genes (∼20.3%) compared with lizards (∼8.9%). The high similarities in dN/dS values were obtained between the branches of large-bodied lizards and large-bodied snakes by Spearman correlation analysis. Combining the results from site model, branch-site model and clade model analyses, we found some key genes regulating the evolution of body size in squamates, such as COL10A1, GHR, NPC1, GALNS, CDKN2C, FBN1, and LCORL. Phylogenetic generalized least squares (PGLS) indicated that AKT1, BMP1, IGF1, SOX5, SOX7 in lizards and BMP5, BMP7, GPC6, SH2B3, SOX17 in snakes were significantly correlated with body length and body mass. Furthermore, ecological factors had varying degrees of impact on body size and the evolutionary rate of body-size-related genes in squamates. Intriguingly, climate had little effect on body size of lizards and snakes, but the contribution of climate-related factors to the variation in evolutionary rate of body-size-related genes were relatively higher. Our study lays a foundation for a comprehensive understanding of genetic mechanisms of body size evolution in squamates during the process of adapting to terrestrial life.
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7
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Sakamoto M. Estimating bite force in extinct dinosaurs using phylogenetically predicted physiological cross-sectional areas of jaw adductor muscles. PeerJ 2022; 10:e13731. [PMID: 35846881 PMCID: PMC9285543 DOI: 10.7717/peerj.13731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 06/23/2022] [Indexed: 01/17/2023] Open
Abstract
I present a Bayesian phylogenetic predictive modelling (PPM) framework that allows the prediction of muscle parameters (physiological cross-sectional area, A Phys) in extinct archosaurs from skull width (W Sk) and phylogeny. This approach is robust to phylogenetic uncertainty and highly versatile given its ability to base predictions on simple, readily available predictor variables. The PPM presented here has high prediction accuracy (up to 95%), with downstream biomechanical modelling yielding bite force estimates that are in line with previous estimates based on muscle parameters from reconstructed muscles. This approach does not replace muscle reconstructions but one that provides a powerful means to predict A Phys from skull geometry and phylogeny to the same level of accuracy as that measured from reconstructed muscles in species for which soft tissue data are unavailable or difficult to obtain.
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8
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Cooke R, Gearty W, Chapman ASA, Dunic J, Edgar GJ, Lefcheck JS, Rilov G, McClain CR, Stuart-Smith RD, Kathleen Lyons S, Bates AE. Anthropogenic disruptions to longstanding patterns of trophic-size structure in vertebrates. Nat Ecol Evol 2022; 6:684-692. [PMID: 35449460 DOI: 10.1038/s41559-022-01726-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 03/07/2022] [Indexed: 11/09/2022]
Abstract
Diet and body mass are inextricably linked in vertebrates: while herbivores and carnivores have converged on much larger sizes, invertivores and omnivores are, on average, much smaller, leading to a roughly U-shaped relationship between body size and trophic guild. Although this U-shaped trophic-size structure is well documented in extant terrestrial mammals, whether this pattern manifests across diverse vertebrate clades and biomes is unknown. Moreover, emergence of the U-shape over geological time and future persistence are unknown. Here we compiled a comprehensive dataset of diet and body size spanning several vertebrate classes and show that the U-shaped pattern is taxonomically and biogeographically universal in modern vertebrate groups, except for marine mammals and seabirds. We further found that, for terrestrial mammals, this U-shape emerged by the Palaeocene and has thus persisted for at least 66 million years. Yet disruption of this fundamental trophic-size structure in mammals appears likely in the next century, based on projected extinctions. Actions to prevent declines in the largest animals will sustain the functioning of Earth's wild ecosystems and biomass energy distributions that have persisted through deep time.
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Affiliation(s)
- Rob Cooke
- UK Centre for Ecology & Hydrology, Wallingford, UK. .,Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden. .,Gothenburg Global Biodiversity Centre, Gothenburg, Sweden.
| | - William Gearty
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA.
| | - Abbie S A Chapman
- Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Jillian Dunic
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Graham J Edgar
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
| | - Jonathan S Lefcheck
- Tennenbaum Marine Observatories Network and MarineGEO Program, Smithsonian Environmental Research Center, Edgewater, MD, USA
| | - Gil Rilov
- National Institute of Oceanography, Israel Limnological and Oceanographic Research, Haifa, Israel
| | | | - Rick D Stuart-Smith
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
| | - S Kathleen Lyons
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Amanda E Bates
- Biology Department, University of Victoria, Victoria, British Columbia, Canada
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Reconstructed evolutionary patterns for crocodile-line archosaurs demonstrate impact of failure to log-transform body size data. Commun Biol 2022; 5:171. [PMID: 35217775 PMCID: PMC8881462 DOI: 10.1038/s42003-022-03071-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 01/25/2022] [Indexed: 02/05/2023] Open
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10
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Reply to: 'Reconstructed evolutionary patterns from crocodile-line archosaurs demonstrate the impact of failure to log-transform body size data'. Commun Biol 2022; 5:170. [PMID: 35217770 PMCID: PMC8881626 DOI: 10.1038/s42003-022-03072-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 01/25/2022] [Indexed: 11/21/2022] Open
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11
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Gearty W, Carrillo E, Payne JL. Ecological Filtering and Exaptation in the Evolution of Marine Snakes. Am Nat 2021; 198:506-521. [PMID: 34559607 DOI: 10.1086/716015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AbstractConvergent evolution is often attributed to adaptation of form to function, but it can also result from ecological filtering, exaptation, or nonaptation. Testing among these possibilities is critical to understanding how and why morphological similarities emerge independently in multiple lineages. To address this challenge, we combined multiple preexisting phylogenetic methods to jointly estimate the habitats and morphologies of lineages within a phylogeny. We applied this approach to the invasions of snakes into the marine realm. We utilized a data set for 1,243 extant snake species consisting of newly compiled biome occupancy information and preexisting data on reproductive strategy, body mass, and environmental temperature and elevation. We find evidence for marine clades arising from a variety of aquatic and terrestrial habitats. Furthermore, there is strong evidence of ecological filtering for nonmarine ancestors that were already viviparous, had slightly larger-than-average body sizes, and lived in environments with higher-than-average temperatures and lower-than-average elevations. In aggregate, similarities among independent lineages of marine snakes result from a combination of exaptation and strong ecological filtering. Strong barriers to entry of new habitats appear to be more important than common adaptations following invasions for producing similarities among independent lineages invading a shared, novel habitat.
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Rio JP, Mannion PD. Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem. PeerJ 2021; 9:e12094. [PMID: 34567843 PMCID: PMC8428266 DOI: 10.7717/peerj.12094] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 08/09/2021] [Indexed: 12/16/2022] Open
Abstract
First appearing in the latest Cretaceous, Crocodylia is a clade of semi-aquatic, predatory reptiles, defined by the last common ancestor of extant alligators, caimans, crocodiles, and gharials. Despite large strides in resolving crocodylian interrelationships over the last three decades, several outstanding problems persist in crocodylian systematics. Most notably, there has been persistent discordance between morphological and molecular datasets surrounding the affinities of the extant gharials, Gavialis gangeticus and Tomistoma schlegelii. Whereas molecular data consistently support a sister taxon relationship, in which they are more closely related to crocodylids than to alligatorids, morphological data indicate that Gavialis is the sister taxon to all other extant crocodylians. Here we present a new morphological dataset for Crocodylia based on a critical reappraisal of published crocodylian character data matrices and extensive firsthand observations of a global sample of crocodylians. This comprises the most taxonomically comprehensive crocodylian dataset to date (144 OTUs scored for 330 characters) and includes a new, illustrated character list with modifications to the construction and scoring of characters, and 46 novel characters. Under a maximum parsimony framework, our analyses robustly recover Gavialis as more closely related to Tomistoma than to other extant crocodylians for the first time based on morphology alone. This result is recovered regardless of the weighting strategy and treatment of quantitative characters. However, analyses using continuous characters and extended implied weighting (with high k-values) produced the most resolved, well-supported, and stratigraphically congruent topologies overall. Resolution of the gharial problem reveals that: (1) several gavialoids lack plesiomorphic features that formerly drew them towards the stem of Crocodylia; and (2) more widespread similarities occur between species traditionally divided into tomistomines and gavialoids, with these interpreted here as homology rather than homoplasy. There remains significant temporal incongruence regarding the inferred divergence timing of the extant gharials, indicating that several putative gavialids ('thoracosaurs') are incorrectly placed and require future re-appraisal. New alligatoroid interrelationships include: (1) support for a North American origin of Caimaninae in the latest Cretaceous; (2) the recovery of the early Paleogene South American taxon Eocaiman as a 'basal' alligatoroid; and (3) the paraphyly of the Cenozoic European taxon Diplocynodon. Among crocodyloids, notable results include modifications to the taxonomic content of Mekosuchinae, including biogeographic affinities of this clade with latest Cretaceous-early Paleogene Asian crocodyloids. In light of our new results, we provide a comprehensive review of the evolutionary and biogeographic history of Crocodylia, which included multiple instances of transoceanic and continental dispersal.
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Affiliation(s)
- Jonathan P. Rio
- Department of Earth Science and Engineering, Imperial College London, London, United Kingdom
| | - Philip D. Mannion
- Department of Earth Sciences, University College London, London, United Kingdom
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13
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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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14
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Stubbs TL, Pierce SE, Elsler A, Anderson PSL, Rayfield EJ, Benton MJ. Ecological opportunity and the rise and fall of crocodylomorph evolutionary innovation. Proc Biol Sci 2021; 288:20210069. [PMID: 33757349 PMCID: PMC8059953 DOI: 10.1098/rspb.2021.0069] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Understanding the origin, expansion and loss of biodiversity is fundamental to evolutionary biology. The approximately 26 living species of crocodylomorphs (crocodiles, caimans, alligators and gharials) represent just a snapshot of the group's rich 230-million-year history, whereas the fossil record reveals a hidden past of great diversity and innovation, including ocean and land-dwelling forms, herbivores, omnivores and apex predators. In this macroevolutionary study of skull and jaw shape disparity, we show that crocodylomorph ecomorphological variation peaked in the Cretaceous, before declining in the Cenozoic, and the rise and fall of disparity was associated with great heterogeneity in evolutionary rates. Taxonomically diverse and ecologically divergent Mesozoic crocodylomorphs, like marine thalattosuchians and terrestrial notosuchians, rapidly evolved novel skull and jaw morphologies to fill specialized adaptive zones. Disparity in semi-aquatic predatory crocodylians, the only living crocodylomorph representatives, accumulated steadily, and they evolved more slowly for most of the last 80 million years, but despite their conservatism there is no evidence for long-term evolutionary stagnation. These complex evolutionary dynamics reflect ecological opportunities, that were readily exploited by some Mesozoic crocodylomorphs but more limited in Cenozoic crocodylians.
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Affiliation(s)
| | - Stephanie E Pierce
- Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Armin Elsler
- School of Earth Sciences, University of Bristol, UK
| | - Philip S L Anderson
- Animal Biology, University of Illinois at Urbana-Champaign, Champaign, IL, USA
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Iijima M, Kubo T. Vertebrae-Based Body Length Estimation in Crocodylians and Its Implication for Sexual Maturity and the Maximum Sizes. Integr Org Biol 2020; 2:obaa042. [PMID: 33791579 PMCID: PMC7891683 DOI: 10.1093/iob/obaa042] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Body size is fundamental to the physiology and ecology of organisms. Crocodyliforms are no exception, and several methods have been developed to estimate their absolute body sizes from bone measurements. However, species-specific sizes, such as sexually mature sizes and the maximum sizes were not taken into account due to the challenging maturity assessment of osteological specimens. Here, we provide a vertebrae-based method to estimate absolute and species-specific body lengths in crocodylians. Lengths of cervical to anterior caudal centra were measured and relations between the body lengths (snout-vent and total lengths [TLs]) and lengths of either a single centrum or a series of centra were modeled for extant species. Additionally, states of neurocentral (NC) suture closure were recorded for the maturity assessment. Comparisons of TLs and timings of NC suture closure showed that most extant crocodylians reach sexual maturity before closure of precaudal NC sutures. Centrum lengths (CLs) of the smallest individuals with closed precaudal NC sutures within species were correlated with the species maximum TLs in extant taxa; therefore, the upper or lower limit of the species maximum sizes can be determined from CLs and states of NC suture closure. The application of the current method to noncrocodylian crocodyliforms requires similar numbers of precaudal vertebrae, body proportions, and timings of NC suture closure as compared to extant crocodylians.
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Affiliation(s)
- Masaya Iijima
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
- Nagoya University Museum, Furocho, Chikusa-Ku, Nagoya, Aichi 464-8601, Japan
- Engineering Research Center for Mineral Resources and Mine Environments, School of Resource and Environmental Engineering, Hefei University of Technology, 193 Tunxi Road, Baohe, Hefei, Anhui 230009, China
| | - Tai Kubo
- The University Museum, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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