''Lomasuchus'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

peirosaurid 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 skull, and were terrestrial carnivores. It was phylogenetically defined ...

notosuchia Notosuchia is a clade of primarily Gondwanan mesoeucrocodylian Crocodylomorpha, crocodylomorphs that lived during the Jurassic and Cretaceous. Some phylogeny, phylogenies recover Sebecosuchia as a clade within Notosuchia, others as a sister group ...

n known from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

(

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 86.3 ± 0.7 mya ( million years ago) and 83.6 ± 0.7 m ...

stage) of

Neuquén Province Neuquén () is a Provinces of Argentina, 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. It also me ...

, western central

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

. It contains a single species, ''Lomasuchus palpebrosus''. It is known only from the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

MOZ 4084 PV which was found in the Loma de la Lata locality of the

Patagonia Patagonia () is a geographical region that includes parts of Argentina and Chile at the southern end of South America. The region includes the southern section of the Andes mountain chain with lakes, fjords, temperate rainforests, and glaciers ...

. It was originally reported as collected from sediments of the

Rio Colorado Subgroup Rio or Río is the Portuguese and Spanish word for "river". The word also exists in Italian, but is largely obsolete and used in a poetical or literary context to mean "stream". Rio, RIO or Río may also refer to: Places United States * Rio, Flo ...

Neuquén Group The Neuquén Group is a geologic unit, 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. It overlies the older Lohan Cura Formation and ...

. Later, Hugo and Leanza (2001) noted that this specimen was actually collected from the underlying

Portezuelo Formation The Portezuelo Formation is a geologic formation of Late Cretaceous (Turonian, Late Turonian to Coniacian, Early Coniacian) age, outcropping in the Mendoza Province, Mendoza, Río Negro Province, Río Negro and Neuquén Province, Neuquén provinc ...

of the

Rio Neuquén Subgroup Rio or Río is the Portuguese and Spanish word for "river". The word also exists in Italian, but is largely obsolete and used in a poetical or literary context to mean "stream". Rio, RIO or Río may also refer to: Places United States * Rio, Fl ...

, Neuquén Group. More recent stratigraphic work on this area identified that horizon as belonging to the younger,

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 89.8 ± 1 Ma and 86.3 ± 0.7 Ma (million years ago). The Coniacian is preceded by ...

-age,

Plottier Formation The Plottier Formation is a geologic formation that outcrops in the Argentine Patagonian provinces of Río Negro and Neuquén. It is the younger of two formations belonging to the Río Neuquén Subgroup within the Neuquén Group of the Neuquén ...

of the Rio Neuquén Subgroup. This horizon is currently considered to pertain to the

-age

Bajo de la Carpa Formation The Bajo de la Carpa Formation is a geologic formation of the Neuquén Basin that outcrop, crops out in northern Patagonia, in the provinces of Río Negro Province, Río Negro and Neuquén Province, Neuquén, Argentina. It is the oldest of two for ...

of the

. ''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'' is an extinct genus of peirosaurid crocodylomorph known from the Late Cretaceous period (late Maastrichtian stage) of Minas Gerais, southern Brazil. It contains a single species, ''Peirosaurus torminni''. It is the type genus of t ...

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

Uberabasuchus ''Uberabasuchus'' ("Uberaba crocodile")''Uberabasuchus''
at

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammals h ...

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 In biological taxonomy, the type genus (''genus typica'') is the genus which defines a biological family and the root of the family name. Zoological nomenclature According to the International Code of Zoological Nomenclature, "The name-bearin ...

), and a

tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide use of the term in English is in the discipline of anthropology. The definition is contested, in part due to conflict ...

called Mahajangasuchini, which included ''

Mahajangasuchus ''Mahajangasuchus'' is an extinct genus of crocodyliform which had blunt, laterally compressed and serrated teeth. The type species, ''M. insignis'', lived during the Late Cretaceous; its fossils have been found in the Maevarano Formation in nort ...

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

Mahajangasuchidae Mahajangasuchidae is an extinct family (biology), family of notosuchian crocodyliforms. It currently contains two genera, ''Mahajangasuchus'' and ''Kaprosuchus'', both of which lived during the Late Cretaceous in Gondwana. It is defined as the mo ...

References

{{Taxonbar, from=Q3281245 Late Cretaceous crocodylomorphs of South America Fossil taxa described in 2012 Terrestrial crocodylomorphs Peirosauridae Bajo de la Carpa Formation Prehistoric pseudosuchian genera Cretaceous Argentina