New Triassic Vertebrate Papers and the Cold Case of the Phytosaurs

After an almost three year hiatus I am looking to start posting again. Is anyone still out there? Did anyone miss me?

Here are a few new Triassic papers officially out today, all open access. A couple were out as early access, but the new phytosaur phylogeny paper is new today in PeerJ. This represents the bulk of the senior authors dissertation, is an exhaustive analysis of the phytosaurs, and a great exercise in database exploration for a group that has been particularly troublesome to deal with taxonomically and phylogenetically.

Phytosaurs are an incredible group of archosauriforms, common in Late Triassic rocks. Although problematic they serve as a great group for students to learn basic cranial and skeletal anatomy and we use them for this purpose at the Petrified Forest. Numerous and diverse they go extinct at the end of the Triassic and that is a mystery that colleagues such as Randall Irmis from the University of Utah are trying to solve. This research was featured last week on Science Friday.

Jones, A. S., and R. J. Butler. 2018. A new phylogenetic analysis of Phytosauria (Archosauria: Pseudosuchia) with the application of continuous and geometric morphometric character coding. PeerJ 6:e5901 DOI 10.7717/peerj.5901

 Marsola, J. C. A., Bittencourt, J. S., Da Rosa, Á. A. S., Martinelli, A. G., Ribeiro, A. M., Ferigolo, J., and M. C. Langer.  2018. New sauropodomorph and cynodont remains from the Late Triassic Sacisaurus site in southern Brazil and its stratigraphic position in the Norian Caturrita Formation. Acta Palaeontologica Polonica 63 (4): 653–669.

Niedźwiedzki, G. and E. Budziszewska-Karwowska. 2018. A new occurrence of the Late Triassic archosaur Smok in southern Poland. Acta Palaeontologica Polonica 68 (4): 703–712.

De Oliveira, T. M., Oliveira, D., Schultz, C. L., Kerber, L., and F. L. Pinheiro. 2018. Tanystropheid archosauromorphs in the Lower Triassic of Gondwana. Acta Palaeontologica Polonica 63 (4): 713–723.

Cartorhynchus lenticarpus, a New Basal Ichthyosauriform from the Lower Triassic of China

Amazing!

Motani, R., Jiang, D.-Y., Chen, G.-B., Tintori, A., Rieppel, O., Ji, C., and J.-D. Huang. 2014. A basal ichthyosauriform with a short snout from the Lower Triassic of China. Nature (article preview). doi:10.1038/nature13866

Abstract - The incompleteness of the fossil record obscures the origin of many of the more derived clades of vertebrates. One such group is the Ichthyopterygia, a clade of obligatory marine reptiles that appeared in the Early Triassic epoch, without any known intermediates. Here we describe a basal ichthyosauriform from the upper Lower Triassic (about 248 million years ago) of China, whose primitive skeleton indicates possible amphibious habits. It is smaller than ichthyopterygians and had unusually large flippers that probably allowed limited terrestrial locomotion. It also retained characteristics of terrestrial diapsid reptiles, including a short snout and body trunk. Unlike more derived ichthyosauriforms, it was probably a suction feeder. The new species supports the sister-group relationships between ichthyosauriforms and Hupehsuchia, the two forming the Ichthyosauromorpha. Basal ichthyosauromorphs are known exclusively from south China, suggesting
that the clade originated in the region, which formed a warm and humid tropical archipelago in the Early Triassic. The oldest unequivocal record of a sauropterygian is also from the same stratigraphic unit of the region.