Named By: E. B. Branson and M. G. Mehl - 1929 (Originally named as Buettneria by case in 1922).
Synonyms: Buettneria perfecta, Metoposaurus bakeri, Metoposaurus maleriensis.
Classification: Chordata, Amphibia, Temnospondyli, Stereospondyli, Metoposauridae.
Species: K. perfecta (type), K. bakeri.
Size: About 3 meters long. Skull about 65 centimeters long.
Known locations: USA, including Arizona - Chinle Formation, New Mexico - Garita Creek Formation, Petrified Forest Formation and Bluewater Creek Formation, Pennsylvania - New Oxford Formation, Texas - Tecovas Formation, and Wyoming - Popo Agie Formation, Chugwater Group. Also known from India - Maleri Formation.
Time period: Carnian to Rhaetian of the Triassic.
Fossil representation: Multiple individuals, the genus is one of the most common found.
was originally named as Buettneria back in 1922,
however it was
later realised that Buettneria had already been
used to name a genus of
katydid (bush cricket). Therefore in 1929 this temnospondyl
amphibian was renamed Koskinonodon. In addition
to this a species of
M. bakeri was moved to create a new species of
Koskinonodon, K. bakeri,
in 1931. Additionally another
species of Metoposaurus, M.
maleriensis is now included with
Koskinonodon is regarded as a metoposaurid temnospondyl amphibian, which means that it is closest to genera such as Metoposaurus and Apachesaurus. These temnopondyls are noted for having eyes that were situated in a more forward position on their skulls than the eyes of other similar temnospondyl groups. Also like its relative genera, Koskinonodon seems to have been more at home in the water where it probably hunted for fish and possibly other amphibians. The limbs are generally not that well supported for terrestrial locomotion, and the presence of a lateral line formed by sensory sulci would have detected changes in water pressure, allowing them to pick up upon the movements of nearby swimming animals.
Further evidence for a mostly aquatic lifestyle can be inferred from collections of Koskinonodon which can be interpreted as mass graves where a body of water dried out, leaving many Koskinonodon exposed to the dry air. The remains of these Koskinonodon are found so close together that they seem to have clustered together in the last remnants of water before death. This may have been the result of a body of water not being replenished by seasonal rain or flood water.
Koskinonodon is best known from the United States, particularly the state of Arizona, where Koskinonodon fossils are known from many members of the Chinle Formation. Remains from India however indicate that Koskinonodon had a much wider distribution than previously thought. Koskinonodon lived in the latter portion of the Triassic, and by the time the Jurassic period started, most of the temnospondyls including Koskinonodon had disappeared. Only a rare few exceptions such as the genera Siderops and Koolasuchus are known to have survived well beyond this point.
- New reptiles and stegocephalians from the Upper Triassic of western Texas - E. C. Case - 1922.
- Triassic amphibians from the Rocky Mountain Region - E. B. Branson & M. G. Mehl. 1929.
- A new metoposaurid amphibian from the Upper Triassic Maleri Formation of central India - T. R. Chowdury - 1965.