TY - JOUR

T1 - A redescription of 'Plesiochelys' tatsuensis from the Late Jurassic of China, with comments on the antiquity of the crown clade Cryptodira

AU - Danilov, Igor G.

AU - Parham, James F.

N1 - Funding Information: The authors wish to express their gratitude to Professor J. Li, Dr. Y. Wang and Ms. F. Zheng (IVPP, Beijing) for access to the turtle collection of IVPP and their hospitality. Ted Papenfuss (Berkeley, USA) provided invaluable assistance to both authors and without him our collaborations on Chinese fossil turtles would be impossible. Walter Joyce is thanked for providing his data matrix prior to it being officially published. This study was done under financial support of a grant of the President of the Russian Federation to the Leading Scientific Schools (NSh-1647.2003.4) and grant of the Russian Foundation for Basic Research (04-05-65000a) to IGD and a National Science Foundation postdoctoral fellowship to JFP. This work is LBNL-61183 and was performed under the auspices of the U.S. Department of Energy, Office of Biological and Environmental Research, by the University of California, Lawrence Berkeley National Laboratory, under contract No. DE-AC03-76SF00098. This is University of California Museum of Paleontology Contribution #1895.

PY - 2006/9/11

Y1 - 2006/9/11

N2 - A reexamination of the holotype of 'Plesiochelys' tatsuensis Yeh, 1963, from the Late Jurassic of China, allows us to establish previously unknown characters of this species. A phylogenetic analysis places 'P.' tatsuensis on the stem of Trionychia, near the clades Adocidae and Nanhsiungchelyidae. Given the hypothesized phylogenetic position of 'P.' tatsuensis, a new genus, Yehguia gen. nov., is erected for this species. The phylogenetic position of Y. tatsuensis pushes the origin of the crown clade Cryptodira into the Late Jurassic. This is remarkable in light of recent studies that moved the origin of crown group turtles (Testudines) from the Triassic to the Late Jurassic. This means that the establishment of basal cryptodiran lineages must have quickly followed the origin of Testudines in the Late Jurassic. The fact that the most ancient fossil Cryptodira is hypothesized to be on the stem of Trionychia is concordant with recent molecular hypotheses that place Trionychia as the most basal extant lineage of Cryptodira. Finally, our results further highlight that the Late Jurassic of China is important for understanding the earliest evolution of cryptodiran turtles.

AB - A reexamination of the holotype of 'Plesiochelys' tatsuensis Yeh, 1963, from the Late Jurassic of China, allows us to establish previously unknown characters of this species. A phylogenetic analysis places 'P.' tatsuensis on the stem of Trionychia, near the clades Adocidae and Nanhsiungchelyidae. Given the hypothesized phylogenetic position of 'P.' tatsuensis, a new genus, Yehguia gen. nov., is erected for this species. The phylogenetic position of Y. tatsuensis pushes the origin of the crown clade Cryptodira into the Late Jurassic. This is remarkable in light of recent studies that moved the origin of crown group turtles (Testudines) from the Triassic to the Late Jurassic. This means that the establishment of basal cryptodiran lineages must have quickly followed the origin of Testudines in the Late Jurassic. The fact that the most ancient fossil Cryptodira is hypothesized to be on the stem of Trionychia is concordant with recent molecular hypotheses that place Trionychia as the most basal extant lineage of Cryptodira. Finally, our results further highlight that the Late Jurassic of China is important for understanding the earliest evolution of cryptodiran turtles.

UR - http://www.scopus.com/inward/record.url?scp=33749440711&partnerID=8YFLogxK

U2 - 10.1671/0272-4634(2006)26[573:AROPTF]2.0.CO;2

DO - 10.1671/0272-4634(2006)26[573:AROPTF]2.0.CO;2

M3 - Article

AN - SCOPUS:33749440711

VL - 26

SP - 573

EP - 580

JO - Journal of Vertebrate Paleontology

JF - Journal of Vertebrate Paleontology

SN - 0272-4634

IS - 3

ER -