[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Steneosaurus edwardsi (Thalattosuchia), largest known crocodylomorph from Middle Jurassic

Ben Creisler

A recent paper not yet mentioned:

Michela M. Johnson, Mark T. Young, Lorna Steel and Yves Lepage (2015)
Steneosaurus edwardsi (Thalattosuchia: Teleosauridae), the largest
known crocodylomorph of the Middle Jurassic.
Biological Journal of the Linnean Society 115(4): 911-918
DOI: 10.1111/bij.12525

Teleosaurids were a clade of marine crocodylomorphs that were globally
distributed during the Jurassic Period. They evolved a wide range of
body sizes, from small (∼2–3 m) to very large (> 9 m). Until now, the
largest known Middle Jurassic teleosaurid was ‘Steneosaurus’
obtusidens, from the Oxford Clay Formation of the UK. Here, we
re-examine a very large Oxford Clay specimen (ilium, ischium, and
femur) that had been tentatively attributed to ‘S.’ obtusidens. Based
on comparative anatomical study with the ‘S.’ obtusidens holotype and
referred specimens of Steneosaurus edwardsi and Steneosaurus leedsi,
we conclude that this very large individual actually pertains to S.
edwardsi. Based on comparisons with the Machimosaurus mosae neotype
(which has a complete femur and skeleton), we estimate a total length
in excess of 7 m for this large S. edwardsi individual, making it the
largest known Middle Jurassic teleosaurid. Therefore, along with the
closely related genus Machimosaurus, this clade of large-bodied
Middle–Late Jurassic teleosaurids were the largest species during the
first 100 million years of crocodylomorph evolution.