''Turseodus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus of ray-finned fish found in Late Triassic

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

sediments of the United States. Two species have been described, ''T. acutus'' from the Lockatong Formation of Pennsylvania, and ''T. dolorensis'' from the

Chinle Formation The Chinle Formation is an Upper Triassic continental geological formation of fluvial, lacustrine, and palustrine to eolian deposits spread across the U.S. states of Nevada, Utah, northern Arizona, western New Mexico, and western Colorado. In Ne ...

of Colorado.

Classification

Although previously placed in the

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

family Palaeoniscidae, ''Turseodus'' was later referred to its own family, Turseoidae, by Wilhelm Bock. The lachrymal bone of ''Turseodus'' forms part of the oral margin, an unusual condition known otherwise only from the

Early Early may refer to: History * The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.: ** Early Christianity ** Early modern Europe Places in the United States * Early, Iowa * Early, Texas * Early ...

to Middle Triassic ''

Pteronisculus ''Pteronisculus'' is an extinct genus of prehistoric ray-finned fish that lived during the Early Triassic and Middle Triassic epochs of the Triassic period. It was first described under the name "''Glaucolepis''" by Erik Stensiö in 1921 and w ...

''. Based on this synapomorphy and other similarities, a close relationship between ''Turseodus'' and ''Pteronisculus'' is hypothesized.C. Romano, A. López-Arbarello, D. Ware, J. F. Jenks, and W. Brinkmann. 2019. Marine Early Triassic Actinopterygii from the Candelaria Hills (Esmeralda County, Nevada, USA). Journal of Paleontology 93:971-1000 https://doi.org/10.1017/jpa.2019.18 There are also similarities with '' Turfania'' from the Permian of

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

. However, a close evolutionary relationship between these genera has not yet been tested by cladistic analyses.

References

Mesozoic animals Prehistoric bony fish genera Palaeonisciformes {{Paleo-rayfinned-fish-stub

Classification

See also

References