''Labidiosuchus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of notosuchian

mesoeucrocodylia Mesoeucrocodylia is the clade that includes Eusuchia and crocodyliforms formerly placed in the paraphyletic group Mesosuchia. The group appeared during the Early Jurassic, and continues to the present day. Diagnosis It was long known that M ...

n from Minas Gerais State, southeastern

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

. ''Labidiosuchus'' had a very bizarre dentition and its lower jaw had a Y-shaped outline.

Discovery

''Labidiosuchus'' is known only from the

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

specimen DGM 1480-R, an incomplete lower jaw with the anterior part of the dentary complete, lacking most of the right mandibular ramus and the end of the left mandibular ramus. It is housed at the Earth Science Museum of the Departamento Nacional da Produção Mineral. A cast is housed at the Departamento de Geologia, Universidade Federal do Rio de Janeiro. It was found in Serra do Veadinho site, Municipality of Peirópolis of Minas Gerais State, from a site in which ''

Itasuchus ''Itasuchus'' is an extinct genus of crocodylomorph from the Late Cretaceous of Brazil. Fossils of the type species ''I. jesuinoi'', first described in 1955 by Llewellyn Ivor Price, have been found from the Serra da Galga Formation (Maastricht ...

'', yet another enigmatic mesoeucrocodylian, was found. It was collected from the

Serra da Galga Formation The Serra da Galga Formation is a geological formation in Minas Gerais state of southeastern Brazil. Its strata date back to the Maastrichtian, and are part of the Bauru Group.It was originally considered a member of the Marília Formation. Dinos ...

(Bauru Group) in the

Bauru Basin The Bauru Group is a geological group of the Bauru Sub-basin, Paraná Basin in Minas Gerais, São Paulo, General Salgado, Itapecuru-Mirim, Mato Grosso, Brazil whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils ...

, which dates to the late

Maastrichtian The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from ...

stage of the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger 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 ''creta'', the ...

Description

''Labidiosuchus'' is characterized by a unique combination of characters, including four autapomorphies (unique characteristics) such as the presence of small teeth on the medial side of the anterior portion of the dentary. ''Labidiosuchus'' had a proportionally large number of the teeth (at least eight on each side of the jaw), packed tightly, some located lateral to each other. The first pair of teeth is procumbent and larger than all others. Its

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...

is strongly anterodorsally projected and there is a symphyseal platform that holds the teeth. Due to the incompleteness of the holotype, its feeding preferences or the exact

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

position can't be determined with certainty. DGM 1480-R was briefly described by Campos & Azevedo (1992) as a

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

lower jaw. The preserved specimen has a length of about and suggests that the jaw had a Y-shaped outline in dorsal view. This condition of the lower jaw is shared with many ziphosuchians, such as ''

Adamantinasuchus ''Adamantinasuchus'' is an extinct genus of notosuchian crocodylomorph from and named after the Late Cretaceous Adamantina Formation of Brazil. It is known from only one fossil, holotype UFRJ-DG 107-R, collected by William Nava (hence the specif ...

'', ''

Sphagesaurus ''Sphagesaurus'' is an extinct genus of sphagesaurid notosuchian crocodylomorph from the Late Cretaceous of southwest São Paulo, southern Brazil. Species and discovery ''Sphagesaurus'' was first described and named by Llewellyn Ivor Price in ...

'',

Notosuchidae Notosuchidae is a Gondwanan family of notosuchians. They were small-bodied terrestrial crocodyliforms that lived during the Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is di ...

and probably with '' Candidodon''. Other characteristics of the dentition which are shared with many members of the Sphagesauridae (such as the strong protruding forward inclination of the first pair of teeth and the presence of anterior projection on the lower jaw) locate it with the Notosuchia, a large group of crocodylomorphs that shows a great variation of dentition.

Etymology

''Labidiosuchus'' was first named by Alexander W. A. Kellner, Rodrigo G. Figueiredo, Sergio A. K. Azevedo and Diogenes A. Campos in

2011 File:2011 Events Collage.png, From top left, clockwise: a protester partaking in Occupy Wall Street heralds the beginning of the Occupy movement; protests against Libyan dictator Muammar Gaddafi, who was killed that October; a young man celebrate ...

and the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

is ''Labidiosuchus amicum''. The generic name is derived from Greek ''labis'' meaning "forceps" or "tongs" and ''souchus'' meaning "crocodile". The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

comes from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''amicus'' meaning "friend", in honor of the community that has helped to protect the palaeontological site at

Peirópolis Peirópolis is a rural district located in Uberaba, Brazil. It is known as a geological-paleontological site, and the location of ''The Paleontological Research Center Llevellyn Ivor Price'', and ''The Dinosaur Museum,'' as many dinosaur fossils ...

, especially the members of the "Association of the Friends of the Peirópolis Palaeontological Site".

References

{{Taxonbar, from=Q6467070 Late Cretaceous crocodylomorphs of South America Terrestrial crocodylomorphs Fossil taxa described in 2011 Ziphosuchians Marília Formation Prehistoric pseudosuchian genera