In Depth
Technosaurus is in simple terms a mess. Described in 1984 by Sankar Chatterjee from an astralgus (ankle bone), a dorsal (back) vertebrae, two lower jaws and a premaxilla, Techonosaurus was heralded as the earliest ornithischian (bird hipped) dinosaur of the time. Then in 1991another palaeontologist named Paul Sereno re-examined the fossils, a study that would be the beginning of the doubt in the validity of Technosaurus being the earliest known ornithischian dinosaur.
First Sereno found that both the vertebrae and astralgus were unidentifiable, and thus could not be used to define the genus. Sereno was also of the opinion that the premaxilla and one of the jaws belonged to a hatchling prosauropod, a kind of saurischian (lizard hipped) dinosaur. A 2007 review by Irmis et al took things even further. It was agreed that the vertebra and astralgus should be removed from the genus, but the reviewers also found no characteristics in the skull and jaw material that could definitely identify them as being dinosaurian. Instead the new review considered the remains to be similar to another archosaur called Shuvosaurus, in fact one of the jaw fragments was considered to actually be from a Shuvosaurus.
Currently Technosaurus only has a premaxilla and a jaw fragment assigned to the genus. Although sometimes tentatively assigned to the dinosauriformes, Technosaurus is now often just described as an indeterminate archosaur. Despite this, Technosaurus has been noted as sharing some similarities with another archosaur called Silesaurus.
Further Reading
- A new ornithischian dinosaur from the Triassic of North America, Sankar Chatterjee - 1984. - Lesothosaurus, “fabrosaurids”, and the early evolution of Ornithischia, Paul C. Sereno - 1991. - A critical re-evaluation of the Late Triassic dinosaur taxa of North America, Sterling J. Nesbitt, Randall B. Irmis, & William G. Parker - 2007. - Early ornithischian dinosaurs: the Triassic record, Sterling J. Nesbitt, Randall B. Irmis, William G. Parker & Jun Lin - 2007.
