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

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 marine lizard belonging to the

mosasaur Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Greek ' meaning 'lizard') comprise a group of extinct, large marine reptiles from the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on th ...

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

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

. 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 A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

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

of ''"P." stadtmani'' consists only of a partial skull and vertebral column (catalogued as

BYU Brigham Young University (BYU, sometimes referred to colloquially as The Y) is a private research university in Provo, Utah. It was founded in 1875 by religious leader Brigham Young and is sponsored by the Church of Jesus Christ of Latter-day S ...

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