New Insights into the Origin and Phylogeny of Cryptodiran Turtles Based on Key Fossil Taxa from the Mesozoic of Asia

DSpace Repository

Show simple item record

dc.contributor.advisor Bocherens, Hervé (Prof. Dr.)
dc.contributor.author Rabi, Márton
dc.date.accessioned 2014-11-27T14:02:16Z
dc.date.available 2014-11-27T14:02:16Z
dc.date.issued 2014-11
dc.identifier.other 420163816 de_DE
dc.identifier.uri http://hdl.handle.net/10900/58007
dc.identifier.uri http://nbn-resolving.de/urn:nbn:de:bsz:21-dspace-580076 de_DE
dc.description.abstract Most turtles from the Jurassic to Early Cretaceous of Asia are referred to the poorly circumscribed taxa Xinjiangchelyidae, Sinemydidae, and Macrobaenidae, groups that mostly include shell-based, generalized, small to mid-sized aquatic forms that are widely considered to represent the stem lineage of Cryptodira. These groups are critical for reconstructing the plesiomorphic anatomy of crown-cryptodires, the most diverse group of living turtles, and they are therefore particularly relevant for understanding the origin and early divergence of the primary clades of extant turtles. The complete description of excellent xinjiangchelyid and sinemydid material from the Upper Jurassic of Mongolia and the Middle Jurassic and Early Cretaceous of China (referable to Annemys levensis, A. latiens, Xinjiangchelys wusu nov. sp. and Manchurochelys manchoukuoensis) provides new insights into the anatomy of these otherwise poorly known groups. The overall similarity of the shells of the two Annemys species combined with significant differences in the skull indicate that these turtles probably partitioned the aquatic niche by exploring different feeding strategies. Among xinjiangchelyids, at least three different skull morphotypes can be differentiated, which implies a moderate level of ecological diversification among Late Jurassic Asian turtles. Phylogenetic definitions of Xinjiangchelyidae, Sinemydidae, and Macrobaenidae are provided for nomenclatural clarity and precision. Phylogenetic analysis weakly supports the inclusion of Xinjiangchelys wusu n. sp., A. levensis, and A. latiens in a monophyletic polytomy with other xinjiangchelyids, including Xinjiangchelys junggarensis and X. radiplicatoides. However, the analysis supports the unorthodox, though tentative placement of xinjiangchelyids and sinemydids outside of crown-group Testudines. A particularly interesting new observation is that the skull of xinjiangchelyids retains such primitive features as a reduced interpterygoid vacuity and basipterygoid processes. The homology of the basipterygoid processes is confidently demonstrated based on a comprehensive review of the basicranial anatomy of Mesozoic turtles and a new nomenclatural system is introduced for the carotid canal system of turtles. The loss of the basipterygoid process and the bony enclosure of the carotid circulation system occurred a number of times independently during turtle evolution suggesting that the reinforcement of the basicranial region was essential for developing a rigid skull, thus paralleling the evolution of other amniote groups with massive skulls. A thorough revision of the phylogeny of Macrobaenidae, Sinemydidae, and closely allied forms yielded two main competing hypotheses: in the first, these taxa form a paraphyletic grade, whereas in the second they form a monophyletic clade. The inclusion of problematic tree changing taxa, such as Panpleurodires (stem + crown side-neck turtles) has a major influence on the phylogenetic relationships of Sinemydidae and closely allied forms. Manchurochelys manchoukuoensis nests within Sinemydidae together with Sinemys spp. and Dracochelys bicuspis in the majority of the analyses. en
dc.language.iso en de_DE
dc.publisher Universität Tübingen de_DE
dc.rights ubt-podok de_DE
dc.rights.uri http://tobias-lib.uni-tuebingen.de/doku/lic_mit_pod.php?la=de de_DE
dc.rights.uri http://tobias-lib.uni-tuebingen.de/doku/lic_mit_pod.php?la=en en
dc.subject.classification Paläontologie , Fossil , Phylogenie , Evolution , Jura , Kreide , Amniota , Schildkröten , Asia , China , Mongolei de_DE
dc.subject.ddc 560 de_DE
dc.subject.other turtle en
dc.subject.other Cryptodira en
dc.subject.other morphology en
dc.subject.other Jurassic en
dc.subject.other Cretaceous en
dc.subject.other phylogeny en
dc.subject.other Mongolia en
dc.title New Insights into the Origin and Phylogeny of Cryptodiran Turtles Based on Key Fossil Taxa from the Mesozoic of Asia en
dc.type Dissertation de_DE
dcterms.dateAccepted 2014-07-30
utue.publikation.fachbereich Geographie, Geoökologie, Geowissenschaft de_DE
utue.publikation.fakultaet 7 Mathematisch-Naturwissenschaftliche Fakultät de_DE
utue.publikation.source Zhou, C.-F†., Rabi, M†. & Joyce, W.G. 2014. A new specimen of Manchurochelys manchoukuoensis from the Early Cretaceous Jehol Biota of Chifeng, Inner Mongolia, China and the phylogeny of Cretaceous basal eucryptodiran turtles. BMC Evolutionary Biology. 14 (77): 1–16. Rabi, M. Sukhanov, V.B., Egorova, V., Danilov, I. & Joyce, W.G. 2014. Osteology, relationships, and ecology of Annemys (Testudines: Eucryptodira) from the Late Jurassic of Shar Teg, Mongolia and a phylogenetic definition Of Xinjiangchelyidae, Sinemydidae, and Macrobaenidae. Journal of Vertebrate Paleontology. 34 (2): 327–352. Rabi, M., Zhou, C.-F., Wings, O., Sun, G., Joyce, W.G. 2013. A New Xinjiangchelyid Turtle from the Middle Jurassic of Xinjiang, China and the evolution of the basipterygoid process in Mesozoic Turtles. BMC Evolutionary Biology. 13 (203): 1–28. de_DE

Dateien:

This item appears in the following Collection(s)

Show simple item record