Abstract
A new eucryptodiran turtle from the Jiufotang Formation of Lamadong, Jianchang County, represents the third turtle taxon, Liaochelys jianchangensis gen. et sp. nov., from the Jehol Biota of western Liaoning Province, China. This taxon is diagnosed by a character combination including a midline contact of the prefrontals, vertebrals wider than long, third costals strongly expanded distally, and a medial contact of the eighth costals. A preliminary cladistic analysis places Liaochelys jianchangensis along the phylogenetic stem of Cryptodira in a position more derived than the taxa, Manchurochelys manchoukuoensis and Ordosemys liaoxiensis, known from the underlying Yixian Formation. This discovery opens a new window into the osteology and evolution of primitive eucryptodiran turtles.References
Batsch, A.J.G.C. (1788) Versuch einer Anleitung, zur Kenntniß und Geschichte der Thiere und Mineralien. I. Akademische Buchhandlung, Jena, 528 pp.
Brinkman, D.B. (2001) New material of Dracochelys (Eucryptodira: Sinemydidae) from the Junggar Basin, Xinjiang, People’s Republic of China. Canadian Journal of Earth Sciences, 38, 1645–1651.
Brinkman, D.B. & Peng, J.-H. (1993a) New material of Sinemys (Testudines, Sinemydidae) from the Early Cretaceous of China. Canadian Journal of Earth Sciences, 30, 2139–2152.
Brinkman, D.B. & Peng, J.-H. (1993b) Ordosemys leios, n. gen., n. sp., a new turtle from the Early Cretaceous of the Ordos Basin, Inner Mongolia. Canadian Journal of Earth Sciences, 30, 2128–2138.
Brinkman, D.B. & Wu, X.-C. (1999) The skull of Ordosemys, an Early Cretaceous turtle from Inner Mongolia, People’s Republic of China, and the interrelationships of Eucryptodira (Chelonia, Cryptodira). Paludicola, 2, 134–147.
Chang, S.-C., Zhang, H., Renne, P.R. & Fang, Y. (2009) High-precision 40Ar/39Ar age for the Jehol Biota. Palaeogeography, Palaeoclimatology, Palaeoecology, 280, 94–104.
Cope, E.D. (1868) On the origin of genera. Proceedings of the Academy of Natural Sciences of Philadelphia, 1868, 242–300.
Danilov, I.G. & Sukhanov, V.B. (2006) A basal eucryptodiran turtle “Sinemys” efremovi (= Wuguia efremovi) from the Early Cretaceous of China. Acta Palaeontologica Polonica, 51, 105–110.
Danilov, I.G., Averianov, A.O., Skutchas, P.P. & Rezvyi, A.S. (2006) Kirgizemys (Testudines, ‘Macrobaenidae’): new material from the Lower Cretaceous of Buryata (Russia) and taxonomic revision. In: Danilov, I.G. & Parham, J.F. (Eds.), Fossil Turtle Research, Volume 1. Russian Journey of Herpetology, 13 (Supplement), pp 46–62.
Endo, R. & Shikama, R. (1942) Mesozoic reptilian fauna in the Jehol mountainland, Manchoukuo. Bulletin of the Central National Museum of Manchoukou, 3, 1–20.
Gaffney, E.S. (1975) A phylogeny and classification of the higher categories of turtles. Bulletin of the American Museum of Natural History, 155, 387–436.
Gaffney, E.S. & Ye, X.-K. (1992) Dracochelys, a new cryptodiran turtle from the Early Cretaceous of China. American Museum Novitates, 3048, 1–13.
Gaffney, E.S., Kool, L., Brinkman, D.B., Rich, T.H. & Vickers-Rich, P. (1998) Otwayemys, a new cryptodiran turtle from the Early Cretaceous of Australia. American Museum Novitates, 3233, 1–28.
Ji, S.-A. (1995) Reptiles. In: Ren, D., Lu, L.-W., Guo, Z.-G. & Ji, S.-A. (Eds.), Fauna and Stratigraphy of Jurassic-Cretaceous in Beijing and the Adjacent Areas. Seismic Press, Beijing, pp 140–146.
Li, J.-L. & Liu, J. (1999) The skull of Manchurochelys liaoxiensis (Testudines: Sinemydidae) from the Yixian Formation of Beipiao, Liaoning and phylogenetic position of this taxon. In: Chen, P.-J. & Jin, F. (Eds.), Jehol Biota. Press of University of Sciences and Technology of China, Hefei, Palaeoworld II, pp 281–295.
Liu, J. (2003) Turtles. In: Chang, M.-M. (Ed.), The Jehol Biota: the Emergence of Feathered Dinosaurs, Beaked Birds and Flowering Plants. Shanghai Scientific and Technical Publishers, Shanghai, p. 117.
Parham, J.F. & Hutchison, J.H. (2003) A new eucryptodiran turtle from the Late Cretaceous of North America (Dinosaur Provincial Park, Alberta, Canada). Journal of Vertebrate Paleontology, 23, 783–798.
Peng, J.-H. & Brinkman, D.B. (1993) New material of Xinjiangchelys (Reptilia: Testudines) from the Late Jurassic Qigu Formation (Shishugou Group) of the Pingfengshan locality, Junggar Basin, Xinjiang. Canadian Journal of Earth Sciences, 30, 2013–2026.
Swofford, D.L. (2002) PAUP*4.0b10. Sinauer Associates, Sunderland, Massachusetts.
Tong, H., Ji, S.-A. & Ji, Q. (2004) Ordosemys (Testudines: Cryptodira) from the Yixian Formation of Liaoning Province, northeastern China: new specimens and systematic revision. American Museum Novitates, 3438, 1–20.
Vandermark, D., Tarduno, J.A., Brinkman, D.B., Cottrell, R.D. & Mason, S. (2009) New Late Cretaceous macrobaenid turtle with Asian affinities from the High Canadian Arctic: dispersal via ice-free polar routes. Geology, 37, 183–186.
Zhou, C.-F. (2010) A second specimen of Manchurochelys manchoukuoensis Endo & Shikama, 1942 from the Early Cretaceous Yixian Formation of western Liaoning, China. Zootaxa, 2534, 57–66.
Zhou, Z.-H., Zhang, F.-C. & Li, Z.-H. (2009) A new basal ornithurine bird (Jianchangornis microdonta gen. et sp. nov.) from the Lower Cretaceous of China. Vertebrata PalAsiatica, 47, 299–310.
Zhou, Z., Zhang, F. & Li, Z. (2010) A new Lower Cretaceous bird from China and tooth reduction in early avian evolution. Proceedings of the Royal Society B, 277, 219–227.