Colognathidae

Colognathids Temporal range: Middle–Late Triassic (Ladinian–Norian) PreꞒ Ꞓ O S D C P T J K Pg N
Partial skull of Quasicolognathus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	incertae sedis
Family:	† Colognathidae Sues, Kligman & Schoch, 2022
Type genus
† Colognathus Case, 1933
Genera
† Colognathus † Quasicolognathus

Colognathidae is an extinct family of enigmatic reptiles. It contains two genera: Colognathus , known from the Late Triassic of the southwestern United States, and the older Quasicolognathus , known from the Middle Triassic of Germany. Both are known from fragmentary remains, mostly comprising tooth-bearing bones of the skull and isolated teeth. The phylogenetic affinities of these taxa have been historically complicated due to their unique anatomy and fragmentary nature; Colognathus was initially described as a unique fish, ^[1] with later researchers suggesting possible affinities with procolophonids, ^[2] lepidosauromorphs, ^[3] and archosauromorphs. ^[4] A 2022 review indicated that research on the relationships of colognathids was ongoing, but that affinities with osteichthyan fishes, procolophonids, and lepidosauromorphs were not supported. ^[5]

Colognathids are characterized by having transversely narrow snouts and unique dental anatomy, exhibiting pleurodont/acrodont implantation. There are only two or three large teeth in the maxilla and dentary (upper and lower tooth-bearing bones), leaving the front of the jaw edentulous (toothless). The posteriormost (further to the back) teeth are greatly enlarged. ^[5]

References

1. Case, E. C. (1928). "Indications of a cotylosaur and of a new form of fish from the Triassic beds of Texas, with remarks on the Shinarump Conglomerate". Journal of the Washington Academy of Sciences. 23 (1): 65. hdl:2027.42/48181.
2. Murry, Phillip A. (1986). "9. Vertebrate paleontology of the Dockum Group, western Texas and eastern New Mexico". In Padian, Kevin (ed.). The Beginning of the Age of Dinosaurs: Faunal change across the Triassic-Jurassic boundary. New York: Cambridge University Press. pp. 109–137. ISBN   978-0-521-30328-6.
3. Heckert, Andrew (2010). Biostratigraphic significance and redescription of the enigmatic vertebrate Colognathus obscurus from the Upper Triassic Chinle Group, southwestern USA. Society of Vertebrate Paleontology, 70th Annual Meeting. pp. 103A–104A.
4. Heckert, Andrew B.; Mitchell, Jonathon S.; Schneider, Vincent P.; Olsen, Paul E. "Diverse New Microvertebrate Assemblage from the Upper Triassic Cumnock Formation, Sanford Subbasin, North Carolina, USA". Journal of Paleontology. 86 (2): 368–390. doi:10.2307/41480198 (inactive 2026-02-08).
5. Sues, Hans-Dieter; Kligman, Ben T.; Schoch, Rainer R. (2022). "An unusual Colognathus-like reptile from the Middle Triassic (Ladinian) Erfurt Formation of Germany". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 303 (2): 227–238. doi:10.1127/njgpa/2022/1046. S2CID   246800490.