Austrocheirus is an extinct genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of neoceratosaurian theropod dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

 which existed during the late Cretaceous period. It was named and described by Martín Ezcurra, Federico Agnolin and Fernando Novas

Fernando Novas

Fernando Emilio Novas is an Argentine paleontologist working for the Comparative Anatomy Department of the Bernardino Rivadavia Natural History Argentine Museum in Buenos Aires...

 in 2010

2010 in paleontology

-Anomalocaridids:-Newly named crustaceans:-Newly named insects:* A new family, Cascopleciidae, is published by Poinar Jr.* A new family of ceraphronoid Hymenopters, Radiophronidae, is published by Ortega-Blanco, Rasnitsyn, and Delclòs....

. It contains the type species

Type species

In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

 Austrocheirus isasii. The generic name means "southern hand". The specific epithet honours discoverer and preparator Marcelo Pablo Isasi.

The fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

s were found on 17 March 2002 in the Pari Aike Formation

Pari Aike Formation

The Pari Aike Formation is a Mesozoic geologic formation. Dinosaur remains are among the fossils that have been recovered from the formation....

, which dates from the Maastrichtian

Maastrichtian

The Maastrichtian is, in the ICS' geologic timescale, the latest age or upper stage of the Late Cretaceous epoch or Upper Cretaceous series, the Cretaceous period or system, and of the Mesozoic era or erathem. It spanned from 70.6 ± 0.6 Ma to 65.5 ± 0.3 Ma...

, around 71 to 65 million years ago. These fossils consist of a partial manus (hand), a tibia

Tibia

The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....

, axial bones

Axial skeleton

The axial skeleton consists of the 80 bones along the central axis of the human body. It is composed of six parts; the human skull, the ossicles of the middle ear, the hyoid bone of the throat, the rib cage, sternum and the vertebral column...

, and a foot bone.

A cladistic analysis indicated Austrocheirus had a basal position in the Abelisauroidea, but was more derived than Ceratosaurus

Ceratosaurus

Ceratosaurus meaning "horned lizard", in reference to the horn on its nose , was a large predatory theropod dinosaur from the Late Jurassic Period , found in the Morrison Formation of North America, in Tanzania and Portugal...

and Berberosaurus

Berberosaurus

Berberosaurus is a genus of abelisauroid theropod dinosaur from the Pliensbachian-Toarcian-age Lower Jurassic Toundoute Continental Series found in the High Atlas of Toundoute, Ouarzazate, Morocco. The type species of the genus Berberosaurus is B. liassicus, in reference to the Lias epoch...

. It is the first known mid-sized abelisauroid which did not possess the reduced forelimbs seen in other members of that clade.