Newtonsaurus

Newtonsaurus is an extinct genus of possibly coelophysoid theropod dinosaur from the Late Triassic (Rhaetian) Lilstock Formation of South Wales, Great Britain. The genus contains a single species, Newtonsaurus cambrensis, originally named as a species of Zanclodon, known from an external mould of the front half of a lower jaw. With an estimated total length of , it is suggested to have been one of the largest theropods known from the Triassic.

== History and classification == thumb|left|1899 illustration of the dentary mould in internal (top) and external (bottom) views Newtonsaurus is only known from the holotype specimen GSM 6532 (a cast was made with the number BMNH R2912), an external mould of a dentary, which was discovered in the Late Triassic (Rhaetian) aged beds of the Lilstock Formation near Bridgend, Wales in 1898 by a mason who gave it to John David, and described by Edwin Tulley Newton in 1899 as a species of Zanclodon: Zanclodon cambrensis, the specific name referring to Cambria, the Latin name for Wales. The taxon was reassigned to ?Megalosaurus by Ralph Molnar in 1990, which was followed by Peter Galton in publications in 1998 and 2005. The species was historically considered to be a nomen dubium, as it apparently lacked diagnostic features used to distinguish it from other theropods. Oliver Rauhut & Hungerbüler in 2000 as well as Darren Naish and David Martill in 2007, considered the fossil to be of a coelophysoid grade theropod outside Averostra based on the low interdental plates and possession of only a single meckelian foramen, a view followed by Roger Benson in a 2010 publication. Matthew Carrano and colleagues in 2012 suggested it was a basal theropod or possibly an indeterminate predatory archosaur outside of Dinosauria.