Phenacolophus

Phenacolophus Temporal range: Late Paleocene–Early Eocene PreꞒ Ꞓ O S D C P T J K Pg N
Dentary material of P. fallax
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Infraclass:	Placentalia
Genus:	† Phenacolophus Matthew & Granger, 1925
Species
Phenacolophus fallax Matthew & Granger, 1925

Phenacolophus is a genus of placental mammal of unknown taxonomic placement from Paleogene Mongolia. ^[1]

Description

Phenacolophus had lophodont molars with low crowns. In form, the lower molars have been compared to Eohippus . The premolars were smaller than the molars, and the canines were greatly enlarged. ^[2]

Classification

The classification history of Phenacolophus is convoluted. The describers of the genus, W. D. Matthew and Walter Granger, proposed that it was of condylarthrine affinity, as well as tentatively suggested Phenacolophus was a litoptern, though they admitted this placement was not likely. ^[2] Other authors suggest Phenacolophus was a basal arsinoithere, based on shared derived characteristics. ^[1] More recently, an altungulate classification has been supported. ^[3] However, altungulates as a group are most likely not a real clade, ^[4] so the true positioning of Phenacolophus is questionable. Some phylogenies still include it with the Embrithopoda (or as a sister clade), whilst others classify it as a stem perissodactyl. ^{[5] [6]}

References

1. McKenna, Malcolm C.; Manning, Earl (1977-09-01). "Affinities and palaeobiogeographic significanceof the Mongolian Paleogene genus Phenacolophus". Geobios. 10: 61–85. Bibcode:1977Geobi..10...61M. doi:10.1016/S0016-6995(77)80008-9. ISSN   0016-6995.
2. Granger, Walter; Matthew, William Diller. "Fauna and correlation of the Gashato Formation of Mongolia. American Museum novitates ; no. 189". Biodiversity Heritage Library. Retrieved 2025-09-29.
3. "The Rise of placental mammals: origins and relationships of the major extant clades". Choice Reviews Online. 43 (5). American Library Association: 43–2801–43-2801. 2006-01-01. doi:10.5860/choice.43-2801 (inactive 29 September 2025).
4. Graur, Dan; Gouy, Manolo; Duret, Laurent (1997-04-01). "Evolutionary Affinities of the Order Perissodactyla and the Phylogenetic Status of the Superordinal Taxa Ungulata and Altungulata". Molecular Phylogenetics and Evolution. 7 (2): 195–200. Bibcode:1997MolPE...7..195G. doi:10.1006/mpev.1996.0391. ISSN   1055-7903.
5. Erdal, Ozan; Antoine, Pierre-Olivier; Sen, Sevket (2016). "New material of Palaeoamasia kansui (Embrithopoda, Mammalia) from the Eocene of Turkey and a phylogenetic analysis of Embrithopoda at the species level". Palaeontology. 59 (5): 631–655. Bibcode:2016Palgy..59..631E. doi:10.1111/pala.12247. ISSN   1475-4983.
6. Gheerbrant, Emmanuel; Filippo, Andrea; Schmitt, Arnaud (2016). "Convergence of Afrotherian and Laurasiatherian Ungulate-Like Mammals: First Morphological Evidence from the Paleocene of Morocco". PLOS ONE. 11 (7) e0157556. Bibcode:2016PLoSO..1157556G. doi: 10.1371/journal.pone.0157556 . ISSN   1932-6203. PMC   4934866 . PMID   27384169.