The first pterosaur trackways from Japan

Abstract

a b s t r a c tIn 1990, five well-preserved pterosaur trackways were discovered in the Kitadani Formation (Lower Cretaceous) of the Kitadani Dinosaur Quarry, Fukui Prefecture, Japan. They occur on the surface of an isolated dark grey siltstone slab (70 Â 50 cm) along with amphibian and bird tracks as well as feeding marks. All pterosaur trackways (a total of 64 imprints) show a clear quadrupedal gait pattern comprising manus and pes prints which reflect their detailed anatomy of the feet. Manus and pes imprint is very small, average 22.6 mm and 21.9 mm long, respectively. The manus has an anteriorly oriented digit I imprint with a medially oriented hook-like sharp claw mark, which makes a high divarication (average 155.4 ) between the posteriorly oriented digit III imprint. The high digital abduction clearly shows that digit I of the manus could be more hyper-extended anteriorly than previously thought: spreading the digits as much as possible would provide a more stable contact with substrate as well as better support the center of pterosaur body mass displaced anteriorly. The interdigital webbing of the pes imprint extends from the metatarso-phalangeal joint near to the bases of four claws. As these features clearly distinguish the Kitadani pterosaur trackways from five known ichnospecies of Pteraichnus, we assign them to a new ichnospecies, Pteraichnus nipponensis. Abundant small pterosaur ichnotaxa from Spain, Korea, and Japan indicate that many small pterodactyloid pterosaur species existed in the Early Cretaceous although there is no single skeletal datum yet.

A manus dominated pterosaur track assemblage from Gansu, China: implications for behavior

“…Subsequently, Pteraichnus has become by far the most prevalent and best preserved pterosaur ichnotaxon. In a recent review Pteraichnus, Lockley and Harris [45] five valid ichnospecies were recognized: P. saltwashensis [43], P. stokesi [16], P. longipodus [46], P. parvus [47], and P. nipponensis [48]. The Pteraichnus trackway from Yanguoxia No.1 tracksite, representing a single individual, was the first pterosaur trackway reported from China [7,8,49].…”

New mammalian specimens from the Lower Cretaceous Kitadani Formation, Tetori Group, Fukui, Japan

“…The sediments in the quarry are fluvial and show several channel-fill deposits and pedogenic horizons in the flood plain deposits that are marked by minor calcrete nodules (Shibata and Goto 2008;Yabe and Shibata 2011). There are also some muddy horizons preserving numerous vertebrate footprints at the quarry (Goto et al 2002;Azuma 2003;Lee et al 2010; Figure 1(C)).…”

First record of the pterosaur footprint Pteraichnus from the Saltwick Formation (Aalenian) of the Cleveland Basin, Yorkshire, UK

“…5). A feature of the Yorkshire specimens is their divarification, which is higher than in other Pteraichnus manus prints, with the exception of a few outlier specimens of P. nipponensis (Lee et al 2010) and of Haenamichnus (Kim et al 2012).…”

“…Both Purbeckopus pentadactylus, which is the only pterosaur print to have been previously described from the British Isles (Wright et al 1997), and Haenamichnus uhangriensis were retained as probably valid (Sánchez-Hernández et al 2009). Two new ichnospecies of Pteraichnus, P. koreanenis (Lee et al 2008) and P. nipponensis (Lee et al 2010), and a second ichnospecies of Haenamichnus, Haenamichnus gainensis (Kim et al 2012), have been recognized and described from Asia.…”