| Noasaurus Fossil range: Late Cretaceous | |
|---|---|
 Noasaurus size comparison. | |
| Scientific classification
| |
| |
Noasaurus ("Northwestern Argentina lizard") is the name given to a carnivorous dinosaur genus of the late Campanian-Maastrichtian (Late Cretaceous). It was a small (less than eight feet long) theropod, specifically a ceratosaur, discovered by Jaime Powell and José Bonaparte in northwestern Argentina. It was originally thought to have had a toe claw similar to that of dromaeosaurs, but independently developed, but this is now discredited: the "toe claw" was probably actually on the animal's hand.
Discovery and naming[]
In the mid-seventies, a fragmentary small theropod skeleton was discovered by Jaime Eduardo Powell and José Fernando Bonaparte at the Estancia El Brete-site. In 1977, the discovery was reported in the scientific literature. The type species, Noasaurus leali, was named and described by Bonaparte and Powell in 1980. The generic name begins with a usual abbreviation of noroeste Argentina, "northwest Argentina". The specific name honours the owner of the site, Fidel Leal.
The holotype, PVL 4061, was found in a layer of the Lecho Formation of Salta Province, Argentina, dating from the late Cretaceous period, more precisely the early Maastrichtian stage, about seventy million years ago. It consists of a partial skeleton with skull. It contains the maxilla, the quadrate bone, two neck vertebrae, two neck ribs, the centrum of a back vertebra, two hand claws, a finger phalanx and the second right metatarsal bone. One of the hand claws was initially identified as a second toe claw. In 2004, it was recognised as a hand claw, at which occasion the second hand claw was referred.
In 1999, a neck vertebra found at the site, specimen MACM 622, was identified as oviraptorosaurian, a rare proof that the Oviraptorosauria had invaded the Gondwanan continents. In 2007 however, it was reidentified as a noasaurid vertebra, probably belonging to the Noasaurus holotype.
Description[]
Compared to those avian-theropods, Noasaurus is old fashioned. It is likely a close relative of the larger abelisaurs that shared its habitat; they are both derived from the same Ceratosaurus-type basal ceratosaurian ancestor. The discovery of Masiakasaurus, a closely related animal from Madagascar, provides evidence for this new theory: it doesn't have a dromaeosaur-style toe claw.
The type species, Noasaurus leali, was described by Bonaparte and Powell in 1980.
Classification[]
References[]
- Lessem, D. (May 1993). "Jose Bonaparte: Master of the Mesozoic". Omni.
External links[]
- http://www.findarticles.com/p/articles/mi_m1430/is_n7_v15/ai_13548874/pg_4
- http://www.thescelosaurus.com/ceratosauria.htm
