''Gnathomortis'' (meaning "jaws of death") is an extinct

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 ...

of marine lizard belonging to the

mosasaur Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Ancient Greek, Greek ' meaning 'lizard') are an extinct group of large aquatic reptiles within the family Mosasauridae that lived during the Late Cretaceous. Their first fossil remains wer ...

family. Fossils of ''Gnathomortis'' have been recovered from the Early

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

Mancos Shale The Mancos Shale or Mancos Group is a Late Cretaceous (Upper Cretaceous) geologic formation of the Western United States. The Mancos Shale was first described by Cross and Purington in 1899 and was named for exposures near the town of Mancos, C ...

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

. The genus contains a single species, ''G. stadtmani'', considered a species of the related ''

Prognathodon ''Prognathodon'' is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Mosasaurinae subfamily, alongside genera like ''Mosasaurus'' and ''Clidastes''. ''Prognathodon'' has been recovered from depos ...

'' up until its 2020 redescription. It was a large mosasaur measuring long. ''Gnathomortis'' was originally named as a species of ''Prognathodon'' in 1999. A phylogenetic analysis by Schulp et al. (2006) found that ''Prognathodon'' species coded in their analysis comprise one

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

, but that "''Prognathodon''" ''stadtmani'' fell outside that clade, and as such did not fit in that genus. Although 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 ...

of ''"P." stadtmani'' consists only of a partial skull and vertebral column (catalogued as BYU 13082), further preparation of the specimen revealed unique features of the quadrate and skull roof, on the basis of which Lively moved it to the new genus ''Gnathomortis'' in 2020.

References

{{Taxonbar, from=Q99546444 Mosasaurines Mosasaurs of North America Fossil taxa described in 2020