Reassessment of the phylogenetic interrelationships of basal turtles (Testudinata)

By Jérémy Anquetin. 2012

92 citations recorded by the source corpus.

Recent discoveries from the Late Triassic and Middle Jurassic have significantly improved the fossil record of early turtles. These new forms offer a unique opportunity to test the interrelationships of basal turtles. Nineteen fossil species are added to the taxon sample of the most comprehensive morphological phylogenetic analysis of the turtle clade. Among these additional species are recently discovered forms (e.g. Odontochelys semitestacea, Eileanchelys waldmani, Condorchelys antiqua), taxa generally omitted from previous analyses (e.g. chengyuchelyids, Sichuanchelys chowi) and species included in a phylogenetic analysis for the first time (Naomichelys speciosa and Siamochelys peninsularis). The coding of several characters is reassessed in the light of recent observations, but also in order to reduce unwarranted assumptions on character and character state homologies. Additional characters from previous analyses, as well as five new ones, are also included, resulting in a data matrix of 178 characters scored for 86 turtle species and seven fossil outgroups. The dataset resolves the relationships of most newly included taxa, with the exception of S. chowi and ‘Chengyuchelys’ dashanpuensis. The phylogenetic placement of Heckerochelys romani, Condorchelys antiqua and Eileanchelys waldmani as stem turtles more derived than Kayentachelys aprix but more basal than Meiolania platyceps and Mongolochelys efremovi is corroborated. The relationships of chengyuchelyids remain unclear and they are unstable with respect to stem turtles. In contrast to previous analyses, Arundelemys dardeni is placed within pleurosternids and Siamochelys peninsularis falls within xinjiangchelyids. Perhaps the most salient conclusion of the present study is the placement of Naomichelys speciosa as a basal member of a clade uniting meiolaniids, Mongolochelys efremovi and Otwayemys cunicularius. This clade of rather large stem turtles had a worldwide spread during the Mesozoic at least, and persisted until the Pleistocene with meiolaniids.

Subfields: Nature and Landscape Conservation, Paleontology

View Paper: https://www.semanticscholar.org/paper/d2fe38454ff932e29acb512f1ef5bf506e8fb6b6

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Citations in the corpus

A new phylogenetic hypothesis of turtles with implications for the timing and number of evolutionary transitions to marine lifestyles in the group (2018, methodology): “In total, 70 characters of Cadena & Parham (2015) were modified (see Coding strategy) and modified versions of 13 characters used by Anquetin (2012), Anquetin et al. (2015), Cadena (2015), Havlik et al. (2014) and Zhou & Rabi (2015) were added.”
A Divergence Dating Analysis of Turtles Using Fossil Calibrations: An Example of Best Practices (2013, methodology): “The Lower to Middle Triassic has produced just one total group testudine, Odontochelys semitestacea Li et al., 2008, and we see no reason to doubt its placement as the oldest unambiguous stem-turtle (Anquetin, 2012).”
A Review of the Fossil Record of Basal Mesozoic Turtles (2017, background): “…of the braincase by the pterygoid, or at least potentially ancestral to other derived characters, such as the otic trochlea relative to the pterygoid trochlea (e.g., Rougier et al. 1995; Sukhanov 2006; Joyce 2007; Sterli 2008; Anquetin 2012; Joyce and Sterli 2012; Joyce, Schoch, and Lyson 2013).”