Coelodus is an extinct genus of marine and possibly freshwater pycnodont fish.[1] It contains only one definitive species, C. saturnus Heckel, 1854 (=C. rosthorni Heckel, 1854, C. suillus Heckel, 1854), from the Late Cretaceous (Turonian to Santonian) of Slovenia.[2] Other species from the Late Jurassic to the Eocene have also been attributed to this genus based on isolated dental elements, but their assignment to Coelodus is uncertain, and this genus likely represents a non-monophyleticwastebasket taxon. A potential diagnostic trait is a prearticular tooth row with three regular highly elongated teeth.[2][3][4][5][6]
Taxonomy
Life restoration of C. saturnus
In addition to C. saturnus, the following are all dubiously classified into this genus:[7][8]
C. anomalus Choffat & Priem 1904 - Barremian of Portugal
C. plethodon Arambourg & Joleaud 1943 - Cenomanian/Turonian of Niger, Maastrichtian of Algeria
C. portucalensis Jonet 1981 - Cenomanian of Portugal
C. priemi Leriche 1903 - Late Jurassic of France
C. ribeiroi Sauvage 1898 - Turonian of Portugal
C. rostratus Gorjanović-Kramberger 1895 - Cenomanian of Slovenia
C. soleri Rullán 1948 - Albian/Cenomanian of Catalonia, Spain
C. stantoni Williston 1900 - Albian of Kansas, USA (Kiowa Shale)
C. subsimilis (Cornuel 1880) Priem 1912 - Late Jurassic of France
C. syriacus Hussakof 1916 - Late Cretaceous of Lebanon
C. vetteri Gorjanović-Kramberger 1895 - Cenomanian-Turonian of Slovenia
C. zambiensis Dartevelle & Casier 1949 - Turonian of the Democratic Republic of the Congo (Kongo Central)
A number of former species in this genus based on complete fossil specimens, such as C. costae Heckel, 1856 (=C. achillis (Costa 1853), C. discus Heckel 1856, C. grandis (Costa 1855), C. pyrrhurus Heckel, 1854) C. subdiscus Wenz, 1989, C. rosadoi Silva Santos, 1963 and C. toncoensis Benedetto & Sanchez ,1972 have since been reclassified into the genera Ocloedus and Costapycnodus, and many of these dentition-only taxa may belong there instead.[2][5] Others, such as the former C. muensteri, are now placed in Anomoeodus.
Indeterminate remains are known from the Csehbánya Formation of Hungary and the Kem Kem Beds of Morocco.[9][10] Notably, these formations, in addition to other formations that Coelodus remains are known from worldwide, are freshwater deposits, suggesting at a potentially amphidromous lifestyle for Coelodus given its occurrence in marine environments as well.[10] It is possible that freshwater and brackish environments served as refugia for Coelodus, allowing for it to survive the Cretaceous-Paleogene extinction event.[11]
