Temporal range: Late Triassic
Trialestes is an extinct genus of Late Triassic crocodylomorph that lived in South America. It has been classified as a dinosaur in the past due it being adapted as a terrestrial, running carnivore. It is classified in Sphenosuchia, which were early relatives of crocodylians. Irmis, Nesbitt and Sues (2013) noted that some of the material referred to this taxon is actually dinosaurian; however, according to the authors, the holotype specimen PVL 2561 "comprises a single individual that preserves unambiguous crocodylomorph synapomorphies", indicating it is indeed a crocodylomorph, and one of the referred specimens, PVL 3889, does share one or more autapomorphies with the holotype, indicating it represents the same taxon.