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Changpeipus (theropod) tracks from Jurassic of Xinjiang, China (free pdf)



From: Ben Creisler
bcreisler@gmail.com

A paper in the new Vertebrata PalAsiatica:


Xing Li-Da,  Hendrik Klein, Martin G. Lockley,  Andreas Wetzel, Li
Zhong-Dong, Li Jian-Jun, Gerard D. Gierliński, Zhang Jian-Ping,
Matsukawa Masaki, Julien D. Divay & Zhou Long (2014)
Changpeipus (theropod) tracks from the Middle Jurassic of the Turpan
Basin, Xinjiang, Northwest China: new discoveries, ichnotaxonomy,
preservation and paleoecology.
Vertebrata PalAsiatica. 52(2): 233–259
http://www.ivpp.cas.cn/cbw/gjzdwxb/xbwzxz/201405/P020140509395995035870.pdf

Theropod footprint assemblages from the Sanjianfang Formation (Middle
Jurassic) at the Shanshan tracksite, Turpan City, Xinjiang, northwest
China are documented and re-described in detail. Together with new
discoveries from this locality, they shed light on the different
preservation and extramorphological variation of a total of 143
footprints. Ichnotaxonomically, they are assigned to the ichnospecies
Changpeipus carbonicus, well known from other Jurassic tracksites of
China. The presence of two distinct morphotypes, as has been
proclaimed in earlier studies, is related to extramorphological
variation on surfaces that indicate a soft, wet and slippery
substrate. Anatomically based features supporting different
ichnospecies are not present. Furthermore, the comparison with similar
footprints from other localities suggests a monotypic ichnogenus
Changpeipus with the type species C. carbonicus. Footprint lengths of
12.2 cm (a few isolated examples) to 47 cm at the Shanshan tracksites
reflect small to medium-sized trackmakers, that can be interpreted
either as different age classes or different biological species.
Peculiar preservational features include a footprint that documents
slipping movement of the pes by three parallel bands obviously
reflecting digits II, III and IV. An associated "normally" impressed
tridactyl footprint suggests that both constitutes a single step. The
depositional environment was a gradually expanding and deepening
lacustrine setting. This is also supported by the co-occurrence of
abundant invertebrate trace fossils. Contrary to earlier
interpretations resulting in an assignment to Lockeia the invertebrate
traces are re-assigned here to the ichnogenus Fuersichnus that can be
attributed to deposit-feeding insect larvae or other invertebrates.
Fuersichnus is a characteristic dwelling and/or feeding burrow of
muddy floodplains or lake margin settings.