Machaeroprosopus

Machaeroprosopus Temporal range: Late Triassic, 228–209 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Skulls in New Mexico
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauromorpha
Clade:	Archosauriformes
Order:	†Phytosauria
Family:	†Parasuchidae
Tribe:	†Mystriosuchini
Genus:	†Machaeroprosopus Mehl et al., 1916 [1]
Type species
†Belodon buceros Cope, 1881
Species
†M. andersoni Mehl, 1922 †M. buceros (Cope, 1881) †M. jablonskiae (Parker & Irmis, 2006) [2] †M. lottorum Hungerbühler et al., 2013 [3] †M. mccauleyi (Ballew, 1989) [4] †M. pristinus (Mehl, 1928) †M. validus Mehl in Mehl et al., 1916 [1]
Synonyms
Arribasuchus Long & Murry, 1995 [5] Machaeroprosopus tenuis Camp, 1930 Pseudopalatus Mehl, 1928

Machaeroprosopus (from Greek: μαχαίρα machaíra, 'large knife' and Greek: πρόσωπος prósōpos, 'bordering on')^[6] is an extinct genus of mystriosuchin leptosuchomorph phytosaur from the Late Triassic of the southwestern United States. M. validus, once thought to be the type species of Machaeroprosopus, was named in 1916 on the basis of three complete skulls from Chinle Formation, Arizona. The skulls have been lost since the 1950s, and a line drawing in the original 1916 description is the only visual record of the specimen.^[7] Another species, M. andersoni, was named in 1922 from New Mexico, and the species M. adamanensis, M. gregorii, M. lithodendrorum, M. tenuis, and M. zunii were named in 1930. Most species have been reassigned to the genera Smilosuchus,^[8] Rutiodon, or Phytosaurus.^[9] Until recently, M. validus was considered to be the only species that has not been reassigned. Thus, Machaeroprosopus was considered to be a nomen dubium or "doubtful name" because of the lack of diagnostic specimens that can support its distinction from other phytosaur genera. However, a taxonomic revision of Machaeroprosopus, conducted by Parker et al. in 2013, revealed that UW 3807, the holotype of M. validus, is not the holotype of Machaeroprosopus, while the species Machaeroprosopus buceros, Machaeroprosopus being a replacement name, with a fixed type species, for Metarhinus, is the combinatio nova of the type species of the genu: Belodon buceros. Therefore, the name Pseudopalatus must be considered a junior synonym of Machaeroprosopus, and all species of the former must be reassigned to the latter.^[10] This revised taxonomy was already accepted in several studies, including Stocker and Butler (2013).^[11] Stocker and Butler (2013) also treated M. andersoni as a valid species,^[11] and not a junior synonym of Machaeroprosopus buceros as was previously suggested by Long and Murry (1995).^[5]