Evolutionary origin of the turtle skull

  title={Evolutionary origin of the turtle skull},
  author={Gabe S. Bever and Tyler R. Lyson and Daniel J. Field and Bhart‐Anjan S. Bhullar},
Transitional fossils informing the origin of turtles are among the most sought-after discoveries in palaeontology. Despite strong genomic evidence indicating that turtles evolved from within the diapsid radiation (which includes all other living reptiles), evidence of the inferred transformation between an ancestral turtle with an open, diapsid skull to the closed, anapsid condition of modern turtles remains elusive. Here we use high-resolution computed tomography and a novel character/taxon… 

Sensory Evolution and Ecology of Early Turtles Revealed by Digital Endocranial Reconstructions

3D digital reconstructions and comparative descriptions of the brain, nasal cavity, neurovascular structures and endosseous labyrinth of Proganochelys quenstedti, one of the earliest stem-turtles, as well as other turtle taxa demonstrate that an increase in size and regionalization of thebrain took place in the course of turtle evolution, achieving an endocast diversity comparable to other amniote groups.

Evolution, Diversity, and Development of the Craniocervical System in Turtles with Special Reference to Jaw Musculature

A hypothetical model for ancestral states and gross morphology of the jaw adductor musculature in Proganochelys quenstedti (the earliest turtle with a complete shell) is proposed, an important step toward the understanding of the evolution of those muscles in turtles.

The origin of the turtle body plan: evidence from fossils and embryos

It is now possible to develop a comprehensive scenario for the sequence of evolutionary changes leading to the formation of the turtle body plan within a phylogenetic framework and evaluate it in light of the ontogenetic development of the shell in extant turtles.

Microanatomy of the stem-turtle Pappochelys rosinae indicates a predominantly fossorial mode of life and clarifies early steps in the evolution of the shell

Bone histological evidence reveals evolutionary changes in bone microstructure in ribs and gastralia approaching the turtle condition and evidence for a predominantly amphibious or fossorial mode of life in Pappochelys, which support the hypothesis that crucial steps in the evolution of the shell occurred in a terrestrial rather than fully aquatic environment.

A toothed turtle from the Late Jurassic of China and the global biogeographic history of turtles

A revision of the global distribution of fossil and recent turtle reveals that the three primary lineages of derived, aquatic turtles, including the crown, Paracryptodira, Pan-Pleurodira, and Pan-Cryptodira can be traced back to the Middle Jurassic of Euramerica, Gondwana, and Asia, respectively, which resulted from the primary break up of Pangaea at that time.

The phylogeny of early amniotes and the affinities of Parareptilia and Varanopidae

A new amniote phylogeny excludes varanopids as stem-line mammals, nests Parareptilia within Diapsida and suggests that temporal fenestration evolved fewer times than previously thought.

Slow and steady: the evolution of cranial disparity in fossil and recent turtles

  • C. FothW. Joyce
  • Environmental Science, Geography
    Proceedings of the Royal Society B: Biological Sciences
  • 2016
The cranial disparity of 172 representatives of the turtle lineage and their ancestors are investigated using two-dimensional geometric morphometrics to find the Mesozoic fragmentation of Pangaea to be a more plausible factor than global warming.



An ancestral turtle from the Late Triassic of southwestern China

A new 220-million-year-old turtle from China is described that documents an intermediate step in the evolution of the shell and associated structures and shows that the turtle shell is not derived from a fusion of osteoderms.

A Middle Triassic stem-turtle and the evolution of the turtle body plan

A new reptile, Pappochelys, is reported that is structurally and chronologically intermediate between Eunotosaurus and Odontochelys and dates from the Middle Triassic period (∼240 million years ago), providing new evidence that the plastron partly formed through serial fusion of gastralia.

A thin-shelled reptile from the Late Triassic of North America and the origin of the turtle shell

The novel observations of Chinlechelys tenertesta lend support to the hypothesis that the turtle shell was originally a complex composite in which dermal armour fused with the endoskeletal ribs and vertebrae of an ancestral lineage instead of forming de novo.

MicroRNAs support a turtle + lizard clade

A novel molecular dataset, the presence versus absence of specific microRNAs, is applied to the problem of the phylogenetic position of turtles and the root of the reptilian tree, and it is found that this dataset unambiguously supports a turtle + lepidosaur group.

Transitional fossils and the origin of turtles

This work reanalysed a recent dataset that allied turtles with the lizard–tuatara clade and found that the inclusion of the stem turtle Proganochelys quenstedti and the ‘parareptile’ Eunotosaurus africanus results in a single overriding morphological signal, with turtles outside Diapsida.

Complete mitochondrial genome suggests diapsid affinities of turtles.

  • R. ZardoyaA. Meyer
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1998
The results challenge the classic view of turtles as the only survivors of primary anapsid reptiles and imply that turtles might have secondarily lost their skull fenestration.

A new Early Permian reptile and its significance in early diapsid evolution

A phylogenetic analysis identifies O. mayorum as the oldest and most basal member of the araeoscelidian sister group, and a new diapsid neatly spans the above gap by appearing 15 Myr after the origin of Diapsida.

Toward consilience in reptile phylogeny: miRNAs support an archosaur, not lepidosaur, affinity for turtles

This work recovers strong support for turtles sharing a more recent common ancestor with archosaurs, and tests the hypothesis with an expanded miRNA presence/absence dataset, and employs more rigorous criteria for miRNA annotation.

An Archosaur-Like Laterosphenoid in Early Turtles (Reptilia: Pantestudines)

The presence in stem turtles of a laterosphenoid ossification identical to that in Archosauriformes is presented, which has been mistakenly dismissed as anatomically dissimilar in these two groups in the past.