Hints of the Early Jehol Biota: Important Dinosaur Footprint Assemblages from the Jurassic-Cretaceous Boundary Tuchengzi Formation in Beijing, China

Abstract

New reports of dinosaur tracksites in the Tuchengzi Formation in the newly established Yanqing Global Geopark, Beijing, China, support previous inferences that the track assemblages from this formation are saurischian-dominated. More specifically, the assemblages appear theropod-dominated, with the majority of well-preserved tracks conforming to the Grallator type (sensus lato), thus representing relatively small trackmakers. Such ichnofaunas supplement the skeletal record from this unit that lacks theropods thus far, proving a larger diversity of dinosaur faunas in that region. Sauropods are represented by medium to large sized and narrow and wide-gauge groups, respectively. The latter correspond with earlier discoveries of titanosauriform skeletons in the same unit. Previous records of ornithischian tracks cannot be positively confirmed. Purported occurrences are re-evaluated here, the trackways and imprints, except of a single possible specimen, re-assigned to theropods. Palecologically the Tuchengzi ichnofauna is characteristic of semi-arid fluvio-lacustrine inland basins with Upper Jurassic-Lower Cretaceous deposits in northern China that all show assemblages with abundant theropod and sauropod tracks and minor components of ornithopod, pterosaur and bird tracks.

The first megatheropod tracks from the Lower Jurassic upper Elliot Formation, Karoo Basin, Lesotho

“…Because larger animals are more likely to have better developed metatarsophalangeal pads [ 76 ], we examine here the importance of the utility of measurements drawn from the metatarsophalangeal pad length (MPL) and metatarsophalangeal surface area (MSA) ( Table 3 ; Fig 7 ). However, it is important to note that the heel and digit surface areas may be variable between tracks and sites, and that several ways of measuring dimensions can be made from line drawings.…”

“…Gierliński et al [ 62 ] have proposed that some large Lower Jurassic tracks may also be considered to be made by (basal) allosaurids, but there are little to no body fossil evidence to support this claim despite the occurrence of these large tracks. Globally, the large theropod dinosaur trackmakers appear more consistently in the Middle to Upper Jurassic, and are mainly thought to be allosaurids and megalosaurids with robust metatarsus and phalanges and inferred well-developed metatarsophalangeal pads [ 64 , 76 ].…”

The Dinosaurian Ichnofauna of the Lower Cretaceous (Valanginian–Barremian) Broome Sandstone of the Walmadany Area (James Price Point), Dampier Peninsula, Western Australia

“…Finally, Xing et al (2015g) described a variety of taxonomically unassigned, very small to medium sauropod tracks/trackways (pedal lengths: 11-55 cm) from the Kimmeridgian-Valanginian Tuchengzi Formation. At least one of those pedal tracks, QJDILL-S1 (lp1; part of a mildly heteropodous trackway), shares with DP11-4 a similar shape and arrangement of tridactyl indentations (Xing et al, 2015g:figs.…”

Late Jurassic–Early Cretaceous trackways of small-sized sauropods from China: New discoveries, ichnotaxonomy and sauropod manus morphology

“…Deltapodus isp. Xing et al (2015b) attributed Morphotype B to small-sized sauropod tracks based on the general trackway pattern with the manus being strongly outward rotated. In terms of sheer numbers, the Qianjiadian tracksite preserves more of these track types than any other locality in China.…”