Cranial ecomorphology of turtles and neck retraction as a possible trigger of ecological diversification

Evolution, Journal Year: 2022, Volume and Issue: 76(11), P. 2566 - 2586

Published: Sept. 19, 2022

Turtles have a highly modified body plan, including rigid shell that constrains postcranial anatomy. Skull morphology and neck mobility may therefore be key to ecological specialization in turtles. However, the signal of turtle skull morphologies has not been rigorously evaluated, leaving uncertainties about roles adaptation convergence. We evaluate cranial ecomorphology using three-dimensional geometric morphometrics phylogenetic comparative methods. shape correlates with allometry, retraction capability, different aquatic feeding ecologies. find variables influence only, whereas functional variable (the capacity for retraction) influences both size. Ecology predictions from are validated by high success rates extant species, outperforming previous two-dimensional approaches. use this infer traits extinct species. Neck evolved among crownward stem-turtles Late Jurassic, signaling decoupling shell, possibly linked major episode ecomorphological diversification. also strong evidence convergent adaptations marine groups. This includes parallel loss retraction, active hunting, possible grazing, suction Our large-scale assessment dietary throughout evolution reveals timing origin their distinct ecomorphologies, highlights potential ecology function effects on form.

Language: Английский

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Digital skull anatomy of the Oligocene North American tortoise Stylemys nebrascensis with taxonomic comments on the species and comparisons with extant testudinids of the Gopherus–Manouria clade

Swiss Journal of Palaeontology, Journal Year: 2024, Volume and Issue: 143(1)

Published: March 5, 2024

The anatomy of North American tortoises is poorly understood, despite a rich fossil record from the Eocene and younger strata. Stylemys nebrascensis particularly noteworthy turtle in this regard, as hundreds specimens are known Oligocene deposits, species one earliest turtles to have been described scientific literature. Since its initial description based on shell, many with more complete material referred nebrascensis. Here, we review confirm referral an important historic specimen nebrascensis, which includes non-shell postcranial, skull material. This allows us document unique features (e.g., unusual 'poststapedial canal' that connects posterior surface cavum acustico-jugulare) refer another well-preserved species. Based computed-tomography scanning these two skulls, provide detailed cranial mandibular osteology has combination plesiomorphic characteristics retention medial jugal process) derived traits shared extant gopher median premaxillary ridge) suggest it may be stem-representative tortoise lineage. supports hypothesis America form geographically restricted clade split Asian relatives during Paleogene.

Language: Английский

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New interpretation of the cranial osteology of the Early Cretaceous turtleArundelemys dardeni(Paracryptodira) based on a CT-based re-evaluation of the holotype

PeerJ, Journal Year: 2021, Volume and Issue: 9, P. e11495 - e11495

Published: May 31, 2021

Arundelemys dardeni is an Early Cretaceous paracryptodire known from a single, incomplete, but generally well-preserved skull. Phylogenetic hypotheses of paracryptodires often find as early branching baenid. As such, it has central role in understanding the evolution successful clade Baenidae, which survived Cretaceous–Paleogene mass extinction, well diversification Paracryptodira into its subclades, recent research suggests to perhaps include helochelydrids, compsemydids, pleurosternids, and baenids. Computer tomography scans holotype material that were produced for initial description Arundelemeys reveal several errors anatomical species, we correct based on element-by-element segmentation. In addition, provide entirely novel information, including descriptions previously undescribed cranial bones, endosseous labyrinth, scutes, latter are unknown most paracryptodires. We interpretation scutes homologizes with those other stem turtles.

Language: Английский

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Cranial and mandibular anatomy of Plastomenus thomasii and a new time-tree of trionychid evolution

Swiss Journal of Palaeontology, Journal Year: 2023, Volume and Issue: 142(1)

Published: March 16, 2023

Abstract Trionychid (softshell) turtles have a peculiar bauplan, which includes shell reductions and cranial elongation. Despite rich fossil record dating back to the Early Cretaceous, evolutionary origin of trionychid bauplan is poorly understood, as even old fossils show great anatomical similarities extant species. Documenting structural detail trionychids may help resolve history group. Here, we study mandibular anatomy Plastomenus thomasii using µCT scanning. belongs Plastomenidae , long-lived (Santonian–Eocene) clade with uncertain affinities among subclades. The skulls known plastomenids are characterized by unusual features otherwise not trionychids, such extremely elongated, spatulate symphyses. We use observations for updated phylogenetic analyses both parsimony Bayesian methods. There strong support across methods stem-cyclanorbine plastomenids. inclusion stratigraphic data in our analysis indicates that range Cretaceous Asian including Perochelys lamadongensis be stem-trionychids, suggesting many evolved prior appearance crown Divergence time estimates from tip-dating Trionychia (134.0 Ma) Pan-Trionychidae (123.8 constrain span during has < 11 million years. rate estimation implies high morphological rates early softshell turtle evolution. If correct, partially fill gap results shallow divergence times cyclanorbines late Eocene.

Language: Английский

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Neuroanatomical Study and Three-Dimensional Cranial Reconstruction of the Brazilian Albian Pleurodiran Turtle Euraxemys essweini

Diversity, Journal Year: 2023, Volume and Issue: 15(3), P. 374 - 374

Published: March 5, 2023

Pleurodira represent one of the two clades that compose crown Testudines, and their temporal range is Late Jurassic–present. However, knowledge about neuroanatomy extinct pleurodires still very limited. In this context, scarce neuroanatomical information Cretaceous clade Euraxemydidae currently available, limited to some characters Moroccan Cenomanian Dirqadim schaefferi. present work, we perform detailed study its sister taxon, Brazilian Albian Euraxemys essweini, based on analysis skull holotype only known individual species. The virtual three-dimensional reconstruction all cranial bones performed, also improving osseous anatomy. different cavities (i.e., cranial, nasal, labyrinthic ones) canals nervous circulatory are compared with those identified thus far for other extant members in order characterize detail.

Language: Английский

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A compsemydid turtle from the Upper Cretaceous of Var, southern France

Annales de Paléontologie, Journal Year: 2022, Volume and Issue: 108(1), P. 102536 - 102536

Published: Jan. 1, 2022

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Cranial osteology, taxonomic reassessment, and phylogenetic relationships of the Early Cretaceous (Aptian-Albian) turtle Trinitichelys hiatti (Paracryptodira)

PeerJ, Journal Year: 2022, Volume and Issue: 10, P. e14138 - e14138

Published: Nov. 2, 2022

We describe the skull of Early Cretaceous (Aptian-Albian) baenid turtle Trinitichelys hiatti using micro-computed tomography to provide new insights into cranial anatomy basal baenids and evolution paracryptodires. show that validity vs Arundelemys dardeni still holds true, most known for which material is share an intriguing combination features are typical either Pleurosternidae or Baenidae, carotid system intermediate pleurosternids more advanced baenids. Our expanded phylogenetic analysis confirms traditional placement dardeni, Lakotemys australodakotensis, as baenids, retrieves Helochelydridae along stem Baenoidea, but recovers Dinochelys whitei, Glyptops ornatus, Dorsetochelys typocardium, Uluops uluops branching Paracryptodira.

Language: Английский

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New data on the shell anatomy of Selenemys lusitanica, the oldest known pleurosternid turtle in Europe

Journal of Iberian Geology, Journal Year: 2024, Volume and Issue: 50(1), P. 105 - 113

Published: Jan. 23, 2024

Abstract One of the most diverse turtle lineages in Upper Jurassic and Lower Cretaceous record Europe is that stem turtles Pleurosternidae (Paracryptodira), also distributed North America. The oldest European representative this lineage Portuguese Selenemys lusitanica , known from upper Kimmeridgian to lower Tithonian levels (Late Jurassic). information on shell taxon so far very limited, being exclusively restricted provided publication which was defined. New specimens several localities Consolação Sub-basin Lusitanian Basin, both Leiria District Lisbon District, are studied here. They include complete species found far, as well isolated plates allow us improve knowledge about it. Thus, new anatomy provided, but its intraspecific variability.

Language: Английский

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New insights into the cranial osteology of the Early Cretaceous paracryptodiran turtle Lakotemys australodakotensis

PeerJ, Journal Year: 2022, Volume and Issue: 10, P. e13230 - e13230

Published: April 12, 2022

Lakotemys australodakotensis is an Early Cretaceous paracryptodire known from two shells and a skull the Lakota Formation of South Dakota, USA. Along with Arundelemys dardeni poorly Trinitichelys hiatti , generally retrieved as early branching baenid, but more insights into cranial anatomy these taxa needed to obtain better understanding paracryptodiran diversity evolution. Here, we describe using micro-computed tomography provide anatomical basis for future phylogenetic analyses that will be investigate precisely intrarelationships Paracryptodira . Preliminary comparisons reveal very similar Aptian-Albian basal baenid both exhibit remarkable combination derived characters found in baenodds non-baenid paracryptodires, particularly Pleurosternidae only date possess canal palatine artery.

Language: Английский

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A well‐preserved cranium from the Judith River Formation (Montana, USA) reveals the inner ear and neuroanatomy of a Campanian baenid turtle

The Anatomical Record, Journal Year: 2023, Volume and Issue: 306(6), P. 1431 - 1451

Published: March 10, 2023

Abstract A cranium belonging to a baenid turtle was recently recovered from the lower half of Judith River Formation, Montana. Badlands Dinosaur Museum (BDM) 004 is well‐preserved partial that includes posterior cranial vault, base, and otic capsules. Based on diagnostic characters, skull can be attributed Plesiobaena antiqua , which has been previously reported Formation. It also shares with palatobaenines projecting processes tubercula basioccipitale prominent condylus occipitalis deep central pit, demonstrating variation within Pl. hypodigm. In phylogenetic analysis, an operational taxonomic unit BDM positioned Baenodda in unresolved polytomy Edowa zuniensis Palatobaeninae, Eubaeninae. Microcomputed tomographic (μCT) scans revealed morphology middle inner ear endocast are largely unknown baenids. Semicircular canals virtually identical those Eubaena cephalica consistent dimensions other taxa, including anterior semicircular robust taller than common crus diverge each at angle approximately 90°. The digital reveals moderately flexed brain rounded cerebral hemispheres minimal separation between metencephalon myelencephalon. Its columella auris (stapes) gracile posterodorsally flared basis columella. arcs across flattens near its terminus. This study adds understanding neuroanatomical expands morphological .

Language: Английский

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