Behavioral and faunal implications of Early Cretaceous deinonychosaur trackways from China

Abstract

Deinonychosaurian theropods, the dinosaurian sister group of birds, are characterized by a large raptorial claw borne on a highly modified second digit that was thought to be held in a retracted position during locomotion. In this study, we present new trackway evidence for two coeval deinonychosaurian taxa from the Early Cretaceous of Shandong, China that indicate a hitherto unrecognized body size diversity for this period and continent. These fossil tracks confirm diversity and locomotory patterns implied by phylogeny and biogeography, but not yet manifested in the body fossil record. Multiple parallel and closely spaced trackways generated by the larger track maker provide the best evidence yet discovered for gregarious behavior in deinonychosaurian theropods.

A diversified vertebrate ichnite fauna from the Feitianshan Formation (Lower Cretaceous) of southwestern Sichuan, China

“…All in all this demonstrates that morphotypes very similar to the Jurassic ichnotaxa Eubrontes, Megalosauripus, Anchisauripus, and Grallator (Olsen et al, 1998) are widely distributed in Lower Cretaceous deposits of China Xing, Lockley, Marty et al, 2015). However, Early Cretaceous Eubrontes tracks generally have larger digit divarication angles than Early Jurassic representatives ; but see Ahlberg, 1994 andLucas et al, 2006 (Kim, Kim, & Lockley, 2008), Dromaeosauripus yongjingensis , and Dromaeopodus shandongensis (Li et al, 2007) Lockley, Gierlinski et al, 2014). Deinonychosaurian tracks are also recorded from Xiaoba Formation of the Panxi region and belong to the Velociraptorichnus morphotype (Xing et al, in press).…”

The socio-sexual behaviour of extant archosaurs: implications for understanding dinosaur behaviour

“…However, the fossil evidence clearly shows trackways spread across several orientations and it is not known why the authors decided to interpret this as evidence of gregariousness when the tracks are so highly random. Matsukawa et al (1997) described a detailed trackway left by 33 members of the inchnogenera Toyamasauripus masuiae from the early Cretaceous beds of Toyama prefecture in central Japan and from Shandong, China, Li et al (2007) reported both closely spaced and multiple parallel trackways considered as evidence for group travel in deinonychosaurs, though no inference to pack hunting was made. The Winton Formation in Queensland, Australia, is famed for the Lark Quarry site which boasts trackways preserved in an ancient mudflat of over 130 small theropod and ornithopod dinosaurs, which apparently went into a stampede triggered by the approach of an individual large theropod Wade 1979, 1984).…”

Diverse dinosaur ichnoassemblages from the Lower Cretaceous Dasheng Group in the Yishu fault zone, Shandong Province, China

“…This is faster than that of Dromaeosauripus yongjingensis (0.75 m/s, Xing et al, 2012), slower than that of Dromaeopodus shandongensis (1.63 m/s; Li et al, 2007;Kim et al, 2008), and much slower than Dromaeosauripus hamanensis (4.86 m/s, Kim et al, 2008).…”