Tawa

Tawa was a sleek, agile predatory dinosaur that lived during the Late Triassic period in what is now New Mexico. Discovered at the famous Ghost Ranch quarry, exceptionally well-preserved and articulated skeletons have given researchers an unusually detailed look at early theropod anatomy. Measuring around two to two and a half metres in length, it was slender with a long neck, small head, and sharp recurved teeth ideal for seizing small prey. It also exhibited early air sacs within its vertebrae, demonstrating that bird-like respiratory systems originated early in dinosaur evolution. Tawa is pivotal to vertebrate palaeontology because it filled a crucial phylogenetic gap between very primitive forms like Herrerasaurus and early neotheropods like Coelophysis. Its coexistence with diverse non-dinosaurian reptiles showed that dinosaurs did not immediately conquer Triassic ecosystems, but gradually found their ecological niche.

Its discovery confirmed that early dinosaurs dispersed across Pangaea in multiple distinct migratory waves.

Where and when

Tawa lived in the Late Triassic, from 215 to 212 million years ago (Norian age). Its remains come from United States, in the Chinle Formation.

The numbers

Length 2.3 m (estimates run from 2 to 2.5 m). Mass about 21 kg. Hip height about 0.7 m. That is 1.4 human-lengths, or 0.21 of a double-decker bus. These are estimates from near-complete skeleton; fields marked estimated by the site are length, mass, hip height.

Compare Tawa with a bus Place on the timeline