A new Anisian (Middle Triassic) eosauropterygian (Reptilia, Sauropterygia) from Panzhou, Guizhou Province, China

An Early Triassic sauropterygian and associated fauna from South China provide insights into Triassic ecosystem health

“…Our result indicates the collapse of monophyly of Eusauropterygia as in most previous studies 16,[20][21][22][23]35,36 . The Pistosauroidea now forms the sister group of the clade including Majiashanosaurus, Hanosaurus, Pachypleurosauria and Nothosauroidea.…”

“…The phylogenetic relationship and stratigraphic occurrence of eosauropterygians ( Fig. 6) here show that the basal position of three Early Triassic eosauropterygians Corosaurus, Majiashanosaurus and Hanosaurus match the stratigraphy quite well compared with previous studies 16,[20][21][22][23]35 .…”

“…However, different from the traditional topology where Pachypleurosauria forms the sister group of Eusauropterygia, in our analysis Pachypleurosauria forms the sister group of Nothosauroidea. This topology is similar to a previous study 20 , but different from most other studies [19][20][21][22][23]35,36 . The Early Triassic pachypleurosaur-like forms Hanosaurus and Majiashanosaurus comprise the consecutive sister groups of the new clade including Pachypleurosauria and Nothosauroidea.…”

“…This traditional topology has received support from several recent studies 19,20 . However, Holmes et al 38 challenged the monophyly of Pachypleurosauria, and many later studies lent support to the collapse of the monophyly of the clade 16,[21][22][23]35,36 .…”

“…The earliest nothosaur, however, did not appear in the geological record until the early Middle Triassic when Germanosaurus and Nothosaurus were reported from Central Europe 14 . The existence of a ghost lineage of nothosaurs thus had to be hypothesized, as framed by the phylogenetic relationship of sauropterygians proposed by previous researchers [19][20][21][22][23] .…”