Trialestes romeri (Bonaparte 1982)=
Triassolestes (Reig, 1963/Tillyard, 1918) Carnian, Late Triassic ~235 mya is known from scattered parts. Clark, Sues and Berman (2000) redescribed the known parts and admitted the possibility that this taxon combined dinosaurian and crocodylomorph characters. As it nests here, Trialestes was derived from a sister to Turfanosuchus , Terrestrisuchus and Gracilisuchus. Trialestes phylogenetically preceded Herrerasaurus and the rest of the dinosaurs.
The skull had no crocodylomorph characters, but the radiale and ulnare were elongated, as in virtually all crocodylomorphs and no dinos. The pelvis was perforated, as in dinosaurs, with a well-developed supraacetabular crest. The femoral head was inturned, suggesting an erect posture. The ankle joint supported that stance with a mesotarsal configuration and a functionally tridactyl pes. The vertebral centra had excavated lateral surfaces, for bird-like air sacs. The radius was a tenth longer than the humerus, a character otherwise known only in dinosaurs. |
