The shell morphology of the latest Cretaceous (Maastrichtian) trionychid turtle Helopanoplia distincta.

ABSTRACT:

Background

Helopanoplia distincta is an extinct soft-shelled turtle (Pan-Trionychidae) for which the type specimen is a fragmentary costal and the inguinal notch portion of the left hypoplastron from the Late Cretaceous (Maastrichtian) Lance Formation of Wyoming, USA that bear a distinct surface sculpture pattern consisting of raised tubercles. Over the course of the past few decades, a number of additional, fragmentary specimens from the Late Cretaceous (Maastrichtian) Hell Creek Formation of Montana and North Dakota have been referred to this taxon based on the presence of these tubercles, but a more complete understanding of the anatomy and phylogenetic relationships of this distinctive soft-shelled turtle is still outstanding.

Methods

We here figure and describe s

SUBMITTER: Joyce WG 

PROVIDER: S-EPMC5733369 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature