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Lyson TR, Bever GS. Origin and Evolution of the Turtle Body Plan. ANNUAL REVIEW OF ECOLOGY, EVOLUTION, AND SYSTEMATICS 2020. [DOI: 10.1146/annurev-ecolsys-110218-024746] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The origin of turtles and their uniquely shelled body plan is one of the longest standing problems in vertebrate biology. The unfulfilled need for a hypothesis that both explains the derived nature of turtle anatomy and resolves their unclear phylogenetic position among reptiles largely reflects the absence of a transitional fossil record. Recent discoveries have dramatically improved this situation, providing an integrated, time-calibrated model of the morphological, developmental, and ecological transformations responsible for the modern turtle body plan. This evolutionary trajectory was initiated in the Permian (>260 million years ago) when a turtle ancestor with a diapsid skull evolved a novel mechanism for lung ventilation. This key innovation permitted the torso to become apomorphically stiff, most likely as an adaption for digging and a fossorial ecology. The construction of the modern turtle body plan then proceeded over the next 100 million years following a largely stepwise model of osteological innovation.
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Affiliation(s)
- Tyler R. Lyson
- Department of Earth Sciences, Denver Museum of Nature & Science, Denver, Colorado 80205, USA
| | - Gabriel S. Bever
- Department of Earth Sciences, Denver Museum of Nature & Science, Denver, Colorado 80205, USA
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Evolution, Diversity, and Development of the Craniocervical System in Turtles with Special Reference to Jaw Musculature. HEADS, JAWS, AND MUSCLES 2019. [DOI: 10.1007/978-3-319-93560-7_8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Cordero GA, Liu H, Wimalanathan K, Weber R, Quinteros K, Janzen FJ. Gene network variation and alternative paths to convergent evolution in turtles. Evol Dev 2018; 20:172-185. [DOI: 10.1111/ede.12264] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Gerardo A. Cordero
- Department of Ecology, Evolution, and Organismal BiologyIowa State UniversityAmesIowa
| | - Haibo Liu
- Program in Bioinformatics and Computational BiologyIowa State UniversityAmesIowa
| | | | - Rachel Weber
- Department of Ecology, Evolution, and Organismal BiologyIowa State UniversityAmesIowa
| | - Kevin Quinteros
- Department of Ecology, Evolution, and Organismal BiologyIowa State UniversityAmesIowa
| | - Fredric J. Janzen
- Department of Ecology, Evolution, and Organismal BiologyIowa State UniversityAmesIowa
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Böhmer C, Werneburg I. Deep time perspective on turtle neck evolution: chasing the Hox code by vertebral morphology. Sci Rep 2017; 7:8939. [PMID: 28827543 PMCID: PMC5566328 DOI: 10.1038/s41598-017-09133-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 07/21/2017] [Indexed: 12/24/2022] Open
Abstract
The unparalleled ability of turtle neck retraction is possible in three different modes, which characterize stem turtles, living side-necked (Pleurodira), and hidden-necked (Cryptodira) turtles, respectively. Despite the conservatism in vertebral count among turtles, there is significant functional and morphological regionalization in the cervical vertebral column. Since Hox genes play a fundamental role in determining the differentiation in vertebra morphology and based on our reconstruction of evolutionary genetics in deep time, we hypothesize genetic differences among the turtle groups and between turtles and other land vertebrates. We correlated anterior Hox gene expression and the quantifiable shape of the vertebrae to investigate the morphological modularity in the neck across living and extinct turtles. This permitted the reconstruction of the hypothetical ancestral Hox code pattern of the whole turtle clade. The scenario of the evolution of axial patterning in turtles indicates shifts in the spatial expression of HoxA-5 in relation to the reduction of cervical ribs in modern turtles and of HoxB-5 linked with a lower morphological differentiation between the anterior cervical vertebrae observed in cryptodirans. By comparison with the mammalian pattern, we illustrate how the fixed count of eight cervical vertebrae in turtles resulted from the emergence of the unique turtle shell.
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Affiliation(s)
- Christine Böhmer
- UMR 7179 CNRS/MNHN, Muséum National d'Histoire Naturelle, 57 rue Cuvier CP-55, 75005, Paris, France.
| | - Ingmar Werneburg
- Senckenberg Center for Human Evolution and Palaeoenvironment at Eberhard Karls Universität, Sigwartstr, 10, 72076, Tübingen, Germany.
- Fachbereich Geowissenschaften, Eberhard Karls Universität, Hölderlinstraße 12, D-72074, Tübingen, Germany.
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung an der Humboldt-Universität zu Berlin, Invalidenstraße 43, 10115, Berlin, Germany.
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Lambertz M. Recent advances on the functional and evolutionary morphology of the amniote respiratory apparatus. Ann N Y Acad Sci 2016; 1365:100-13. [PMID: 27037667 DOI: 10.1111/nyas.13022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 01/14/2016] [Accepted: 01/19/2016] [Indexed: 12/30/2022]
Abstract
Increased organismic complexity in metazoans was achieved via the specialization of certain parts of the body involved in different faculties (structure-function complexes). One of the most basic metabolic demands of animals in general is a sufficient supply of all tissues with oxygen. Specialized structures for gas exchange (and transport) consequently evolved many times and in great variety among bilaterians. This review focuses on some of the latest advancements that morphological research has added to our understanding of how the respiratory apparatus of the primarily terrestrial vertebrates (amniotes) works and how it evolved. Two main components of the respiratory apparatus, the lungs as the "exchanger" and the ventilatory apparatus as the "active pump," are the focus of this paper. Specific questions related to the exchanger concern the structure of the lungs of the first amniotes and the efficiency of structurally simple snake lungs in health and disease, as well as secondary functions of the lungs in heat exchange during the evolution of sauropod dinosaurs. With regard to the active pump, I discuss how the unique ventilatory mechanism of turtles evolved and how understanding the avian ventilatory strategy affects animal welfare issues in the poultry industry.
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Affiliation(s)
- Markus Lambertz
- Institut für Zoologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
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Cordero GA, Quinteros K. Skeletal remodelling suggests the turtle's shell is not an evolutionary straitjacket. Biol Lett 2016; 11:20150022. [PMID: 25878046 DOI: 10.1098/rsbl.2015.0022] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Recent efforts to decipher the enigma of the turtle's shell revealed that distantly related turtle species deploy diverse processes during shell development. Even so, extant species share in common a shoulder blade (scapula) that is encapsulated within the shell. Thus, evolutionary change in the correlated development of the shell and scapula probably underpins the evolution of highly derived shell morphologies. To address this expectation, we conducted one of the most phylogenetically comprehensive surveys of turtle development, focusing on scapula growth and differentiation in embryos, hatchlings and adults of 13 species. We report, to our knowledge, the first description of secondary differentiation owing to skeletal remodelling of the tetrapod scapula in turtles with the most structurally derived shell phenotypes. Remodelling and secondary differentiation late in embryogenesis of box turtles (Emys and Terrapene) yielded a novel skeletal segment (i.e. the suprascapula) of high functional value to their complex shell-closing system. Remarkably, our analyses suggest that, in soft-shelled turtles (Trionychidae) with extremely flattened shells, a similar transformation is linked to truncated scapula growth. Skeletal remodelling, as a form of developmental plasticity, might enable the seemingly constrained turtle body plan to diversify, suggesting the shell is not an evolutionary straitjacket.
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Affiliation(s)
- Gerardo Antonio Cordero
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, 251 Bessey Hall, Ames, IA 50011, USA
| | - Kevin Quinteros
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, 251 Bessey Hall, Ames, IA 50011, USA
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Joyce WG. The origin of turtles: a paleontological perspective. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2015; 324:181-93. [PMID: 25712176 DOI: 10.1002/jez.b.22609] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 10/27/2014] [Indexed: 11/10/2022]
Abstract
The origin of turtles and their unusual body plan has fascinated scientists for the last two centuries. Over the course of the last decades, a broad sample of molecular analyses have favored a sister group relationship of turtles with archosaurs, but recent studies reveal that this signal may be the result of systematic biases affecting molecular approaches, in particular sampling, non-randomly distributed rate heterogeneity among taxa, and the use of concatenated data sets. Morphological studies, by contrast, disfavor archosaurian relationships for turtles, but the proposed alternative topologies are poorly supported as well. The recently revived paleontological hypothesis that the Middle Permian Eunotosaurus africanus is an intermediate stem turtle is now robustly supported by numerous characters that were previously thought to be unique to turtles and that are now shown to have originated over the course of tens of millions of years unrelated to the origin of the turtle shell. Although E. africanus does not solve the placement of turtles within Amniota, it successfully extends the stem lineage of turtles to the Permian and helps resolve some questions associated with the origin of turtles, in particular the non-composite origin of the shell, the slow origin of the shell, and the terrestrial setting for the origin of turtles.
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Affiliation(s)
- Walter G Joyce
- Department of Geoscience, University of Fribourg, Fribourg, Switzerland
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Aspden JW, Armstrong CL, Gutierrez-Ibanez CI, Hawkes R, Iwaniuk AN, Kohl T, Graham DJ, Wylie DR. Zebrin II / aldolase C expression in the cerebellum of the western diamondback rattlesnake (Crotalus atrox). PLoS One 2015; 10:e0117539. [PMID: 25692946 PMCID: PMC4334253 DOI: 10.1371/journal.pone.0117539] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/27/2014] [Indexed: 11/19/2022] Open
Abstract
Aldolase C, also known as Zebrin II (ZII), is a glycolytic enzyme that is expressed in cerebellar Purkinje cells of the vertebrate cerebellum. In both mammals and birds, ZII is expressed heterogeneously, such that there are sagittal stripes of Purkinje cells with high ZII expression (ZII+), alternating with stripes of Purkinje cells with little or no expression (ZII-). The patterns of ZII+ and ZII- stripes in the cerebellum of birds and mammals are strikingly similar, suggesting that it may have first evolved in the stem reptiles. In this study, we examined the expression of ZII in the cerebellum of the western diamondback rattlesnake (Crotalus atrox). In contrast to birds and mammals, the cerebellum of the rattlesnake is much smaller and simpler, consisting of a small, unfoliated dome of cells. A pattern of alternating ZII+ and ZII- sagittal stripes cells was not observed: rather all Purkinje cells were ZII+. This suggests that ZII stripes have either been lost in snakes or that they evolved convergently in birds and mammals.
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Affiliation(s)
- Joel W. Aspden
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada, T6G 2E9
| | - Carol L. Armstrong
- Department of Biology, Mount Royal University, 4825 Mount Royal Gate SW, Calgary, Alberta, Canada, T3E 6K6
| | - Cristian I. Gutierrez-Ibanez
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada, T6G 2E9
- Lehrstuhl für Zoologie, Technische Universität München, Liesel-Beckmann Straße 4, 85354, Freising-Weihenstephan, Germany
| | - Richard Hawkes
- Department of Cell Biology & Anatomy, Genes and Development Research Group, and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada, T2N 4N1
| | - Andrew N. Iwaniuk
- Department of Neuroscience, Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada, T1K 3M4
| | - Tobias Kohl
- Lehrstuhl für Zoologie, Technische Universität München, Liesel-Beckmann Straße 4, 85354, Freising-Weihenstephan, Germany
| | - David J. Graham
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada, T6G 2E9
| | - Douglas R. Wylie
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada, T6G 2E9
- * E-mail:
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Li YI, Kong L, Ponting CP, Haerty W. Rapid evolution of Beta-keratin genes contribute to phenotypic differences that distinguish turtles and birds from other reptiles. Genome Biol Evol 2013; 5:923-33. [PMID: 23576313 PMCID: PMC3673632 DOI: 10.1093/gbe/evt060] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Sequencing of vertebrate genomes permits changes in distinct protein families, including gene gains and losses, to be ascribed to lineage-specific phenotypes. A prominent example of this is the large-scale duplication of beta-keratin genes in the ancestors of birds, which was crucial to the subsequent evolution of their beaks, claws, and feathers. Evidence suggests that the shell of Pseudomys nelsoni contains at least 16 beta-keratins proteins, but it is unknown whether this is a complete set and whether their corresponding genes are orthologous to avian beak, claw, or feather beta-keratin genes. To address these issues and to better understand the evolution of the turtle shell at a molecular level, we surveyed the diversity of beta-keratin genes from the genome assemblies of three turtles, Chrysemys picta, Pelodiscus sinensis, and Chelonia mydas, which together represent over 160 Myr of chelonian evolution. For these three turtles, we found 200 beta-keratins, which indicate that, as for birds, a large expansion of beta-keratin genes in turtles occurred concomitantly with the evolution of a unique phenotype, namely, their plastron and carapace. Phylogenetic reconstruction of beta-keratin gene evolution suggests that separate waves of gene duplication within a single genomic location gave rise to scales, claws, and feathers in birds, and independently the scutes of the shell in turtles.
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Affiliation(s)
- Yang I Li
- Department of Physiology, Anatomy and Genetics, MRC Functional Genomics Unit, University of Oxford, United Kingdom
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Joyce WG, Schoch RR, Lyson TR. The girdles of the oldest fossil turtle, Proterochersis robusta, and the age of the turtle crown. BMC Evol Biol 2013; 13:266. [PMID: 24314094 PMCID: PMC4077068 DOI: 10.1186/1471-2148-13-266] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 11/26/2013] [Indexed: 12/02/2022] Open
Abstract
Background Proterochersis robusta from the Late Triassic (Middle Norian) of Germany is the oldest known fossil turtle (i.e. amniote with a fully formed turtle shell), but little is known about its anatomy. A newly prepared, historic specimen provides novel insights into the morphology of the girdles and vertebral column of this taxon and the opportunity to reassess its phylogenetic position. Results The anatomy of the pectoral girdle of P. robusta is similar to that of other primitive turtles, including the Late Triassic (Carnian) Proganochelys quenstedti, in having a vertically oriented scapula, a large coracoid foramen, a short acromion process, and bony ridges that connect the acromion process with the dorsal process, glenoid, and coracoid, and by being able to rotate along a vertical axis. The pelvic elements are expanded distally and suturally attached to the shell, but in contrast to modern pleurodiran turtles the pelvis is associated with the sacral ribs. Conclusions The primary homology of the character “sutured pelvis” is unproblematic between P. robusta and extant pleurodires. However, integration of all new observations into the most complete phylogenetic analysis that support the pleurodiran nature of P. robusta reveals that this taxon is more parsimoniously placed along the phylogenetic stem of crown Testudines. All current phylogenetic hypotheses therefore support the basal placement of this taxon, imply that the sutured pelvis of this taxon developed independently from that of pleurodires, and conclude that the age of the turtle crown is Middle Jurassic.
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Affiliation(s)
- Walter G Joyce
- Department of Geosciences, University of Tübingen, Hölderlinstr, 12, 72074 Tübingen, Germany.
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Joyce WG, Werneburg I, Lyson TR. The hooked element in the pes of turtles (Testudines): a global approach to exploring primary and secondary homology. J Anat 2013; 223:421-41. [PMID: 24102560 PMCID: PMC4399356 DOI: 10.1111/joa.12103] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2013] [Indexed: 01/06/2023] Open
Abstract
The hooked element in the pes of turtles was historically identified by most palaeontologists and embryologists as a modified fifth metatarsal, and often used as evidence to unite turtles with other reptiles with a hooked element. Some recent embryological studies, however, revealed that this element might represent an enlarged fifth distal tarsal. We herein provide extensive new myological and developmental observations on the hooked element of turtles, and re-evaluate its primary and secondary homology using all available lines of evidence. Digital count and timing of development are uninformative. However, extensive myological, embryological and topological data are consistent with the hypothesis that the hooked element of turtles represents a fusion of the fifth distal tarsal with the fifth metatarsal, but that the fifth distal tarsal dominates the hooked element in pleurodiran turtles, whereas the fifth metatarsal dominates the hooked element of cryptodiran turtles. The term 'ansulate bone' is proposed to refer to hooked elements that result from the fusion of these two bones. The available phylogenetic and fossil data are currently insufficient to clarify the secondary homology of hooked elements within Reptilia.
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Affiliation(s)
- Walter G Joyce
- Department of Geosciences, University of Tübingen, Tübingen, Germany; Department of Geosciences, University of Fribourg, Fribourg, Switzerland
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Lyson TR, Bhullar BAS, Bever GS, Joyce WG, de Queiroz K, Abzhanov A, Gauthier JA. Homology of the enigmatic nuchal bone reveals novel reorganization of the shoulder girdle in the evolution of the turtle shell. Evol Dev 2013; 15:317-25. [DOI: 10.1111/ede.12041] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tyler R. Lyson
- Department of Geology and Geophysics; Yale University; New Haven CT 06511 USA
- Division of Vertebrate Paleontology; Yale Peabody Museum of Natural History; New Haven CT 06511 USA
- Department of Vertebrate Zoology; National Museum of Natural History, Smithsonian Institution; Washington DC 20560 USA
| | - Bhart-Anjan S. Bhullar
- Department of Geology and Geophysics; Yale University; New Haven CT 06511 USA
- Department of Organismic and Evolutionary Biology; Harvard University; Cambridge MA 02138 USA
| | - Gabe S. Bever
- Department of Geology and Geophysics; Yale University; New Haven CT 06511 USA
- Department of Anatomy; New York Institute of Technology, College of Osteopathic Medicine; New York NY USA
- Division of Paleontology; American Museum of Natural History; New York NY USA
| | - Walter G. Joyce
- Department of Geosciences; University of Tübingen; 72074 Tübingen Germany
- Division of Vertebrate Paleontology; Yale Peabody Museum of Natural History; New Haven CT 06511 USA
| | - Kevin de Queiroz
- Department of Vertebrate Zoology; National Museum of Natural History, Smithsonian Institution; Washington DC 20560 USA
| | - Arhat Abzhanov
- Department of Organismic and Evolutionary Biology; Harvard University; Cambridge MA 02138 USA
| | - Jacques A. Gauthier
- Department of Geology and Geophysics; Yale University; New Haven CT 06511 USA
- Division of Vertebrate Paleontology; Yale Peabody Museum of Natural History; New Haven CT 06511 USA
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Evolutionary Origin of the Turtle Shell. Curr Biol 2013; 23:1113-9. [DOI: 10.1016/j.cub.2013.05.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 04/03/2013] [Accepted: 05/01/2013] [Indexed: 11/30/2022]
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Jones MEH, Werneburg I, Curtis N, Penrose R, O'Higgins P, Fagan MJ, Evans SE. The head and neck anatomy of sea turtles (Cryptodira: Chelonioidea) and skull shape in Testudines. PLoS One 2012; 7:e47852. [PMID: 23144831 PMCID: PMC3492385 DOI: 10.1371/journal.pone.0047852] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 09/19/2012] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Sea turtles (Chelonoidea) are a charismatic group of marine reptiles that occupy a range of important ecological roles. However, the diversity and evolution of their feeding anatomy remain incompletely known. METHODOLOGY/PRINCIPAL FINDINGS Using computed tomography and classical comparative anatomy we describe the cranial anatomy in two sea turtles, the loggerhead (Caretta caretta) and Kemp's ridley (Lepidochelys kempii), for a better understanding of sea turtle functional anatomy and morphological variation. In both taxa the temporal region of the skull is enclosed by bone and the jaw joint structure and muscle arrangement indicate that palinal jaw movement is possible. The tongue is relatively small, and the hyoid apparatus is not as conspicuous as in some freshwater aquatic turtles. We find several similarities between the muscles of C. caretta and L. kempii, but comparison with other turtles suggests only one of these characters may be derived: connection of the m. adductor mandibulae internus into the Pars intramandibularis via the Zwischensehne. The large fleshy origin of the m. adductor mandibulae externus Pars superficialis from the jugal seems to be a characteristic feature of sea turtles. CONCLUSIONS/SIGNIFICANCE In C. caretta and L. kempii the ability to suction feed does not seem to be as well developed as that found in some freshwater aquatic turtles. Instead both have skulls suited to forceful biting. This is consistent with the observation that both taxa tend to feed on relatively slow moving but sometimes armoured prey. The broad fleshy origin of the m. adductor mandibulae externus Pars superficialis may be linked to thecheek region being almost fully enclosed in bone but the relationship is complex.
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Affiliation(s)
- Marc E H Jones
- Research Department of Cell and Developmental Biology, UCL, University College London, London, England, United Kingdom.
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