Silesauridae


Silesauridae is an extinct clade of Triassic dinosauriformes consisting of the closest known relatives of dinosaurs. As indicated by coprolite contents, some silesaurids such as Silesaurus may have been insectivorous, feeding selectively on small beetles and other arthropods.

Classification

Silesauridae is the sister group to Dinosauria. The group was named in 2010 by paleontologist Max C. Langer et al. They defined it as a branch-based clade of all archosaurs closer to Silesaurus opolensis than to either Heterodontosaurus tucki or Marasuchus lilloensis. At the same time, a second group of scientists independently named Silesauridae as a node-based clade consisting of Lewisuchus, Silesaurus, their last common ancestor and all their descendants. Currently, both definitions encompass the same group of animals. In a later paper, Sterling J. Nesbitt et al. noted that the earlier definition by Langer et al. did not include a diagnosis, and so was not sufficient to create a ranked family-level name according to the ICZN. Therefore, the family Silesauridae is attributed to Nesbitt et al. while the clade Silesauridae is attributed to Langer et al..
The fossils range in age from the Anisian to the Norian stages of the Triassic, about 245 to 203 million years ago. The cladogram below follows the phylogenetic analysis of basal ornithodirans conducted by Christian Kammerer, Sterling Nesbitt and Neil Shubin with clade terminology from Cau and Martz and Small.
A large phylogenetic analysis of early dinosaurs and dinosauromorphs carried out by Matthew Baron, David Norman and Paul Barrett and published in the journal Nature recovered Silesauridae as a monophyletic sister group to Dinosauria. The study also recovered the taxon Agnosphitys within the clade Silesauridae, close to Lewisuchus and its synonymous taxon Pseudolagosuchus.