Colognathus

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Colognathus
Temporal range: Late Triassic, Norian
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: incertae sedis
Family:† Colognathidae
Genus:† Colognathus
Case, 1933
Type species
†Xenognathus obscurus
Case, 1928
Synonyms [1]

Colognathus is an extinct genus of enigmatic reptile from Late Triassic (Norian age) rocks of the southwestern United States. The genus contains a single species, Colognathus obscurus, described in 1928 by Ermine C. Case based on a jaw fragment. Case interpreted the specimen as belonging to a unique form of fish. Later analyses suggested possible relationships with procolophonid 'parareptiles. Alongside the German Quasicolognathus , it is currently placed in the family Colognathidae, the relationships of which are unclear.

Contents

Distribution

Approximately 25 specimens have been found as of 2007. [2] A great many of the reptile's fossils are from the Tecovas Formation of western Texas. Other finds of Colognathus were from places such as the Palo Duro Canyon (in western Texas) and the Santa Rosa Formation (in New Mexico). [2] One tooth is known from the Blue Mesa Member of the Chinle Formation at Petrified Forest National Park, Arizona. Material from the Middle Triassic (Ladinian) Lower Keuper of southern Germany was originally assigned to Colognathus sp., which would extend the temporal range of the form back to the Middle Triassic. [3] In 2022, these remains, in addition to a partial skull, were described as belonging to a new Colognathus-like taxon, Quasicolognathus , together forming the new family Colognathidae. [4]

Classification

Colognathus was originally named Xenognathus by Ermine Cowles Case in 1928, [5] but that name was preoccupied, so Case provided the replacement name Colognathus in 1933. [1] Researchers have classified Colognathus as a reptile, although its lower-level classification remains uncertain, although it may be a procolophonid. [2] [6]

References

  1. 1 2 Case, E. C. (1933). "Colognathus proposed for Xenognathus, preoccupied". Contributions from the Museum of Paleontology, University of Michigan. 3 (1): 65. JSTOR   24530279.
  2. 1 2 3 Heckert, Andrew B. (2007). "Colognathus obscurus Case, an unusual vertebrate index fossil of Adamanian (St. Johnsian: Latest Carnian) time, from the Upper Triassic of the American Southwest". Geological Society of America Abstracts with Programs. 2007 GSA Denver Annual Meeting (28–31 October 2007). Vol. 39. p. 30.
  3. ↑ Sues, Hans-Dieter; Schoch, Rainer R. (2013). "First record of Colognathus (?Amniota) from the Middle Triassic of Europe". Journal of Vertebrate Paleontology. 33 (4): 998–1002. Bibcode:2013JVPal..33..998S. doi:10.1080/02724634.2013.732977. S2CID   83951152.
  4. ↑ 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.
  5. ↑ 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.
  6. ↑ Schoch, Rainer R. (2011). "A procolophonid-like tetrapod from the German Middle Triassic". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 259 (2): 251–255. doi:10.1127/0077-7749/2011/0124.
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