Chilenosuchus 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 aetosaur

Aetosaur

Aetosaurs are an extinct order of heavily armoured, medium- to large-sized Late Triassic herbivorous archosaurs. They have small heads, upturned snouts, erect limbs, and a body covered by plate-like scutes. All aetosaurs belong to the family Stagonolepididae...

. Fossil

Fossil

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

s have been found from the Antofagasta Region

Antofagasta Region

The II Antofagasta Region is one of Chile's fifteen first-order administrative divisions. It comprises three provinces, Antofagasta, El Loa and Tocopilla...

 in northern Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

. The presence of Chilenoasaurus in the beds that it was found in conflicts with the inferred age of the strata. Fossil plants and invertebrates suggest that it dates back to the late Carboniferous

Carboniferous

The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...

 or early Permian

Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

, yet Chilenoasaurus is an aetosaur, and the first aetosaurs appeared in the Late Triassic

Late Triassic

The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...

. Poor-quality photographs of the original specimen and an apparent lack of substantial material could not allow for definite classification of the specimen, so there was initially much controversy as to whether or not the fossil was from a true aetosaur. However, a reevaluation in 2003 upon the relocation of the material showed that it was in fact an aetosaur and that the strata were of Triassic age.

Based on similarities in the armour plating, Chilenosuchus seems to be closely related to Typothorax

Typothorax

Typothorax is an extinct genus of aetosaur that lived in the Late Triassic. Its remains have been found in North America. Two species are known: T. coccinarum, the type species, and T. antiquum.-Description:...

. It has been proposed to be a member of a recently devised clade, Typothoracisinae

Typothoracisinae

Typothoracisinae is a clade of aetosaurs within the subfamily Aetosaurinae. It is a stem-based taxon defined as all aetosaurs closer to Typothorax than to Stagonolepis or Desmatosuchus. As with many aetosaur taxa, most of the synapomorphies that diagnose the clade are found in the osteoderms...

, along with Typothorax and several other similar aetosaurs. However, because of the many other differences between it and other aetosaurs, the position of Chilenosuchus within Stagonolepididae will remain uncertain until more material can be found.