Tawa hallae (Nesbitt et al. 2009) Late Triassic ~2m in length was a basal theropod dinosaur. Derived from a sister to Herrerasaurus, Tawa was basal to all other theropods, like Coelophysis and Segisaurus.

Distinct from Herrerasaurus the naris is larger and lower. The jugal is deeper. The neck was longer with more cervicals. The torso was shorter. The tail was longer.

The pectoral girdle was more gracile. The fingers increased in length from 1 to 3, which is distinct from most theropods. The pelvis and hind limb were more gracile. The metatarsals were more symmetrical.

As one of the basalmost dinosaurs, Tawa was also closely related to the smaller basal phytodinosaur, Eodromaeus and basamost dinosaur, Buriolestes. See below.

Falcatakely forsterae (O'Connor et al. 2020 Late Cretaceous) was originally considered an enantiornithine bird, but here nests with Tawa at the base of the Theropoda. Note the tiny premaxillary teeth and lack of an antorbital fenestra in both taxa. This represents a separate lineage of theropods evolving into bird-mimics after splitting in the Triassic.

Ptychotherates bucculentus (Srivastava and Nesbittt 2026, Late Triassic, New Mexico, CM 31368) was originally considered close to Tawa, Chindesaurus and Daemonosaurus together creating the clade Morphororaptora within Herrerasauria. Here Ptychotherates is reconstructed similar to Tawa only, but with a deeper mandible and smaller quadrate. The two were likely congeneric and both were basal theropods.

Pendraig milnerae (Spiekman et al. 2021; Late Triassic, NHMUK PV R 37591) was originally considered a coelophysid, but here nests at the base of the coelophysids and all other theropods other than Tawa and the Marasuchus clade. The specimen consists of a pelvis, sacrum and femur.

Nesbitt SJ, Smith ND, Irmis RB, Turner AH,Downs A and Norell, MA 2009. A complete skeleton of a Late Triassic saurischian and the early evolution of dinosaurs", Science 326 (5959):1530–1533.

O'Connor PM, Turner A H, Groenke JR et al. 2020. Late Cretaceous bird from Madagascar reveals unique development of beaks. Nature. doi:10.1038/s41586-020-2945-x

Spiekman SNF, Ezcurra MD, Butler RJ, Fraser NC and Maidment SCR 2021. Pendraig milnerae, a new small-sized coelophysoid theropod from the Late Triassic of Wales. Royal Society Open Science 8:210915. https://doi.org/10.1098/rsos.210915

Srivastava S and Nesbitt SJ 2026. A new taxon of saurischian dinosaur from the Coelophysis Quarry of New Mexico, USA (Triassic: latest Norian or Rhaetian) highlights herrerasaurian diversity in the latest Triassic. Papers in Palaeontology. 12 (2) e70069. doi:10.1002/spp2.70069

wiki/Tawa
wiki/Pendraig
wiki/Falcatakely
wiki/Ptychotherates