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Xing L.,China University of Geosciences | Lockley M.G.,University of Colorado at Denver | Marty D.,Naturhistorisches Museum Basel | Pinuela L.,Museo del Jurasico de Asturias MUJA Jurassic Museum of Asturias | And 3 more authors.
Cretaceous Research

A re-description of the Early Cretaceous Zhaojue dinosaur tracksite (Sichuan Province, China) is the major focus of the present work. The tracksite is located in an active copper mine, and a dinosaur track-bearing surface of about 1500m2 (named tracksite I) initially discovered in 1991, has since almost completely collapsed due to ongoing quarry activities. Only about 5% of the initial surface still remains in place (named "remaining tracksite"), while due to the collapse a few new but rather poorly-preserved tracks were unearthed on an underlying level. While the tracks still in place were studied using common field techniques, a schematic tracksite map of the collapsed surface was drawn based on a "corrected orthophotograph" that was generated from overview photographs and from video frames. Fortunately, the resolution of some of the close-up video frames is sufficiently high to observe general track morphology, and to re-interpret previously wrongly identified trackways. Here, we report a quite diverse ichnocoenosis consisting of sauropod, ornithopod, theropod, and pterosaur trackways and isolated tracks. The sauropod trackways belong to the Brontopodus-type and were possibly left by medium-sized titanosaurs. One of the sauropod trackways turns around and makes an astonishingly narrow turn of more than 180° with very pronounced "off-tracking" of the manus with respect to the pes. Such unusual trackways are important for the reconstruction of sauropod locomotion. The theropod trackways were left by small and medium-sized animals with the imprint morphology being similar to that of the ichnogenera Grallator and Eubrontes. Large tridactyl tracks with blunt toes are tentatively identified as ornithopod tracks and may be described as Caririchnium-type tracks. Pterosaur tracks can be assigned to Pteraichnus. The association of pterosaur with small theropod tracks is rather unusual, and this tracksite further corroborates the frequent presence of large ornithopods in inland environmental settings. © 2014 Elsevier Ltd. Source

Xing L.,China University of Geosciences | Lockley M.G.,University of Colorado at Denver | Marty D.,Naturhistorisches Museum Basel | Zhang J.,China University of Geosciences | And 13 more authors.

The historically-famous Lotus Fortress site, a deep 1.5-3.0-meter-high, 200-meter-long horizonal notch high up in near-vertical sandstone cliffs comprising the Cretaceous Jiaguan Formation, has been known since the 13th Century as an impregnable defensive position. The site is also extraordinary for having multiple tetrapod track-bearing levels, of which the lower two form the floor of part of the notch, and yield very well preserved asseamblages of ornithopod, bird (avian theropod) and pterosaur tracks. Trackway counts indicate that ornithopods dominate (69%) accounting for at least 165 trackmakers, followed by bird (18%), sauropod (10%), and pterosaur (3%). Previous studies designated Lotus Fortress as the type locality of Caririchnium lotus and Wupus agilis both of which are recognized here as valid ichnotaxa. On the basis of multiple parallel trackways both are interpreted as representing the trackways of gregarious species. C. lotus is redescribed here in detail and interpreted to indicate two age cohorts representing subadults that were sometimes bipedal and larger quadrupedal adults. Two other previously described dinosaurian ichnospecies, are here reinterpreted as underprints and considered nomina dubia. Like a growing number of significant tetrapod tracksites in China the Lotus Fortress site reveals new information about the composition of tetrapod faunas from formations in which the skeletal record is sparse. In particular, the site shows the relatively high abundance of Caririchium in a region where saurischian ichnofaunas are often dominant. It is also the only site known to have yielded Wupus agilis. In combination with information from other tracksites from the Jiaguan formation and other Cretaceous formations in the region, the track record is proving increasingly impotant as a major source of information on the vertebrate faunas of the region. The Lotus Fortress site has been developed as a spectacular, geologically-, paleontologicallyand a culturally-significant destination within Qijiang National Geological Park. © 2015 Xing et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source

Xing L.,China University of Geosciences | Buckley L.G.,Peace Region Palaeontology Research Center | McCrea R.T.,Peace Region Palaeontology Research Center | Lockley M.G.,University of Colorado at Denver | And 4 more authors.

Trace fossils provide the only records of Early Cretaceous birds from many parts of the world. The identification of traces from large avian track-makers is made difficult given their overall similarity in size and tridactyly in comparison with traces of small non-avian theropods. Reanalysis of Wupus agilis from the Early Cretaceous (Aptian-Albian) Jiaguan Formation, one of a small but growing number of known avian-pterosaur track assemblages, of southeast China determines that these are the traces of a large avian track-maker, analogous to extant herons. Wupus, originally identified as the trace of a small non-avian theropod track-maker, is therefore similar in both footprint and trackway characteristics to the Early Cretaceous (Albian) large avian trace Limiavipes curriei from western Canada, and Wupus is reassigned to the ichnofamily Limiavipedidae. The reanalysis of Wupus reveals that it and Limiavipes are distinct from similar traces of small to medium-sized non-avian theropods (Irenichnites, Columbosauripus, Magnoavipes) based on their relatively large footprint length to pace length ratio and higher mean footprint splay, and that Wupus shares enough characters with Limiavipes to be reassigned to the ichnofamily Limiavipedidae. The ability to discern traces of large avians from those of small non-avian theropods provides more data on the diversity of Early Cretaceous birds. This analysis reveals that, despite the current lack of body fossils, large wading birds were globally distributed in both Laurasia and Gondwana during the Early Cretaceous. Copyright: © 2015 Xing et al. Source

Xing L.,China University of Geosciences | Lockley M.G.,University of Colorado at Denver | Pinuela L.,Museo del Jurasico de Asturias MUJA Jurassic Museum of Asturias | Zhang J.,China University of Geosciences | And 3 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology

The Lotus Fortress tracksite in the Qijiang National Geological Park, in Qijiang District, Chongqing Municipality consists of two distinct assemblages associated with different surfaces (Qijiang Layers 1 and 2). The lower of these two assemblages, here labeled as the ". Wupus- Pteraichnus ichnoassemblage" is dominated by multiple, mainly parallel trackways of a small tridactyl and five trackways of pterosaurs ( Pteraichnus). The upper surface assemblage, here labeled as the ". Caririchnium ichnoassemblage", is dominated by the tracks of ornithopods ( Caririchnium lotus). Here we give a detailed description of the Pteraichnus tracks and evaluate their paleoecological significance together with other reports of pterosaur tracks from East Asia. © 2013 Elsevier B.V. Source

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