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Theropod tracks from Jurassic of Chongqing,China (free pdf)
From: Ben Creisler
A new open access paper in Vertebrata PalAsiatica:
XING Li-Da, Martin G. LOCKLEY, CHEN Wei, Gerard D. GIERLIŃSKI, LI
Jian-Jun, W. Scott PERSONS IV, Masaki MATSUKAWA, YE Yong, Murray K.
GINGRAS & WANG Chang-Wen (2013)
Two theropod track assemblages from the Jurassic of Chongqing, China,
and the Jurassic stratigraphy of Sichuan Basin.
Vertebrata PalAsiatica 51(2): 107-130
Four Jurassic dinosaur tracksites have been reported from Chongqing
Municipality. These include the Lower Jurassic Dazu site in the
Zhenzhuchong Formation, which yields the oldest sauropod trackway
known from China. Two of the remaining three sites (Nan’an, and Jinji
sites), variously regarded as Middle and Upper Jurassic, are here
described in detail for the first time and regarded as Upper Jurassic,
both from the Shangshaximiao Formation. The fourth site (Chengyu), so
far not accessible to the present authors, is not described. The
Nan’an site, and type locality of Chongqingpus nananensis, has yielded
a large sample of theropod tracks from the heart of Chongqing
Municipality, at a site that has been lost in the urban development.
Fortunately the sample is preserved at Chongqing Museum of Natural
History and has been studied independently on two occasions to produce
the results presented here. C. nananensis is a medium-sized track
(mean track length ~29 cm) that may best be accommodated in ichngenus
Kayentapus, and may in some cases preserve ill-defined hallux traces.
Associated tracks are attributed to cf. Anomoepus. Other smaller
ichnospecies from other localities outside Chongqing municipality, and
from older middle Middle Jurassic formations, were previously assigned
to ichnogenus Grallator. The Jinji site has yielded a single long
theropod trackway of a robust form tentatively labeled
cf.Therangospodus. This Jinji trackway also provides intermittent
evidence of a hallux. Althoughtheropod tracks are becoming
increasingly well-known in the Jurassic sections of
ChongqingMunicipality, the Sichuan Basin and the broader region,
determining their precise age and assigning them to valid ichnotaxa
remain challenging. This is because Jurassic theropod tracks,despite
being abundant, show a continuous range of morphological, and
preservational variation that is difficult to define and differentiate
in space and time.