M. buceros was first described and named by Edward Drinker Cope in 1881 as Belodon buceros, on the basis of the holotype AMNH 2318, partial skull.
It was collected from the Norian-aged Petrified Forest Member of the Chinle Formation, at the Arroyo Seco drainage, Orphan Mesa in the Rio Arriba County of New Mexico.
Later, the skull was occasionally referred to Phytosaurus buceros Jaekel (1910) erected a new genus for the species, creating Metarhinus buceros, however this generic name was preoccupied by Metarhinus Osborn, 1908, a brontotheriid mammal.
Mehl (1915) referred this species to Lophoprosopus, as Lophoprosopus buceros, but as the type species of this genus is considered to be synonymous with Nicrosaurus kapffi, Mehl (1916) erected a new genus for B. buceros, creating Machaeroprosopus buceros, and then named a new species of the genus, M. validus.
Subsequent studies considered M. validus to be the type species of Machaeroprosopus.
Later, the skull was referred to as Rutiodon buceros, Machaeroprosopus buceros or Pseudopalatus buceros.
Long and Murry (1995) erected a new genus for the species, not knowing that M. validus was not in fact the type species of Machaeroprosopus, creating Arribasuchus buceros.
Subsequent studies, including Hungerbühler (2002), Lucas et al. (
2002), Zeigler et al. (
2002), Irmis (2005) and Parker and Irmis (2006), referred the species back to Pseudopalatus buceros, and considered Arribasuchus to be a junior synonym of Pseudopalatus.
A taxonomic revision of Machaeroprosopus, conducted by Parker et al. (
in press), revealed that Pseudopalatus buceros has priority as the type species of the genus.
Therefore, the name Pseudopalatus was considered a junior synonym of Machaeroprosopus, and all species of the former were reassigned to the later, including P. buceros.
Following the revision, M. andersoni was treated as a valid species by Stocker and Butler (2013), and not a junior synonym of Machaeroprosopus buceros as was previously suggested by Long and Murry (1995).
Other specimens were referred to P. buceros by Long and Murry (1995), although all specimens from Arizona and Texas was later reassigned to other species (namely M. lottorum, M. mccauleyi and M. validus), and as M. andersoni from the Dockum Group was re-validated, M. buceros is currently known only from Chinle Formation of New Mexico.
M. buceros was first described and named by Edward Drinker Cope in 1881 as Belodon buceros, on the basis of the holotype AMNH 2318, partial skull. It was collected from the Norian-aged Petrified Forest Member of the Chinle Formation, at the Arroyo Seco drainage, Orphan Mesa in the Rio Arriba County of New Mexico. Later, the skull was occasionally referred to Phytosaurus buceros Jaekel (1910) erected a new genus for the species, creating Metarhinus buceros, however this generic name was preoccupied by Metarhinus Osborn, 1908, a brontotheriid mammal. Mehl (1915) referred this species to Lophoprosopus, as Lophoprosopus buceros, but as the type species of this genus is considered to be synonymous with Nicrosaurus kapffi, Mehl (1916) erected a new genus for B. buceros, creating Machaeroprosopus buceros, and then named a new species of the genus, M. validus. Subsequent studies considered M. validus to be the type species of Machaeroprosopus. Later, the skull was referred to as Rutiodon buceros, Machaeroprosopus buceros or Pseudopalatus buceros. Long and Murry (1995) erected a new genus for the species, not knowing that M. validus was not in fact the type species of Machaeroprosopus, creating Arribasuchus buceros. Subsequent studies, including Hungerbühler (2002), Lucas et al. (2002), Zeigler et al. (2002), Irmis (2005) and Parker and Irmis (2006), referred the species back to Pseudopalatus buceros, and considered Arribasuchus to be a junior synonym of Pseudopalatus. A taxonomic revision of Machaeroprosopus, conducted by Parker et al. (in press), revealed that Pseudopalatus buceros has priority as the type species of the genus. Therefore, the name Pseudopalatus was considered a junior synonym of Machaeroprosopus, and all species of the former were reassigned to the later, including P. buceros. Following the revision, M. andersoni was treated as a valid species by Stocker and Butler (2013), and not a junior synonym of Machaeroprosopus buceros as was previously suggested by Long and Murry (1995). Other specimens were referred to P. buceros by Long and Murry (1995), although all specimens from Arizona and Texas was later reassigned to other species (namely M. lottorum, M. mccauleyi and M. validus), and as M. andersoni from the Dockum Group was re-validated, M. buceros is currently known only from Chinle Formation of New Mexico.
Machaeroprosopus