Lomasuchus 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 peirosaurid

Peirosauridae

Peirosauridae is a Gondwanan family of mesoeucrocodylians that lived during the Cretaceous period. It was a clade of terrestrial crocodyliforms that evolved a rather dog-like form, and were terrestrial carnivores. It was phylogenetically defined in 2004 as the most recent common ancestor of...

 mesoeucrocodylia

Mesoeucrocodylia

Mesoeucrocodylia is the name of the clade that includes Eusuchia and the paraphyletic group Mesosuchia. The group appeared during the Early Jurassic, and continues to the present day....

n. 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 Bajo de la Carpa Formation

Bajo de la Carpa Formation

The Bajo de la Carpa Formation is a geologic formation that outcrops in Patagonia, in the provinces of Río Negro and Neuquén, Argentina. It is the first of two formations belonging to the Río Colorado Subgroup within the Neuquén Group...

 of the Neuquén Group

Neuquén Group

The Neuquén Group is a group of geologic formations found in Argentina. Rocks in the Neuquén Group fall within the Cenomanian to early Campanian stages of the Late Cretaceous Period, about 100 million to 80 million years in age...

 outcropping in Neuquén Province

Neuquén Province

Neuquén is a province of Argentina, located in the west of the country, at the northern end of Patagonia. It borders Mendoza Province to the north, Rio Negro Province to the southeast, and Chile to the west...

, Argentina

Argentina

Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

. The formation dates back to the Late Cretaceous

Late Cretaceous

The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

, although the exact time of deposition is unknown (it most likely formed during either the Coniacian

Coniacian

The Coniacian is an age or stage in the geologic timescale. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series and spans the time between 89.3 ± 1 Ma and 85.8 ± 0.7 Ma...

 or Santonian

Santonian

The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series. It spans the time between 85.8 ± 0.7 mya and 83.5 ± 0.7 mya...

 stage).

Lomasuchus had a deep, narrow snout characteristic of peirosaurids. The serrated teeth were compressed, although not to the extent seen in other related genera such as Peirosaurus

Peirosaurus

Peirosaurus is an extinct genus of peirosaurid crocodylomorph. It is the type genus of the family Peirosauridae. Fossils of the type species P. tormini, first described in 1955, have been found from the Marília Formation in Uberaba, Brazil and date back to the late Maastrichtian stage of the Late...

. Many similarities can be seen between its morphology and that of the related Uberabasuchus

Uberabasuchus

Uberabasuchus is an extinct genus of crocodylomorph from the Late Cretaceous of Brazil.-Sources:* - original description of genus...

, such as the narrow snout and a groove at the maxilla

Maxilla

The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...

-premaxilla

Premaxilla

The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....

 contact that accommodated for an enlarged fourth mandibular tooth. The two genera are distinguished from one another on the basis of several features, including the shape of the orbits.

Lomasuchus lends its name to a subfamily of peirosaurids called the Lomasuchinae. Lomasuchinae was constructed in 2004 and included Lomasuchus (the type genus

Type genus

In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...

), and a tribe

Tribe (biology)

In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...

 called Mahajangasuchini, which included Mahajangasuchus

Mahajangasuchus

Mahajangasuchus is an extinct genus of crocodyliform which had blunt, conical teeth. The type species, M. insignis, lived during the Late Cretaceous; its fossils have been found in the Maevarano Formation in northern Madagascar.Sereno et al....

and Uberabasuchus. Mahajangasuchus is now placed outside Peirosauridae in a different family, Mahajangasuchidae

Mahajangasuchidae

Mahajangasuchidae is an extinct family of neosuchian crocodyliforms. It currently contains two genera, Mahajangasuchus and Kaprosuchus, both of which lived during the Late Cretaceous in Gondwana...

.

External links

• Lomasuchus in the Paleobiology Database
  Paleobiology Database
  ' is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms.-History:The Paleobiology Database was founded in 2000. It has been funded by the National Science Foundation and the Australian Research Council...