''Psilichthys'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of prehistoric

bony fish Osteichthyes ( ; ), also known as osteichthyans or commonly referred to as the bony fish, is a Biodiversity, diverse clade of vertebrate animals that have endoskeletons primarily composed of bone tissue. They can be contrasted with the Chondricht ...

from

Eumeralla Formation The Eumeralla Formation is a geological formation in Victoria, Australia whose strata date back to the Early Cretaceous. It is Aptian to Albian in age. Dinosaur remains are among the fossils that have been recovered from the formation, particul ...

, the

Lower Cretaceous Lower may refer to: * ''Lower'' (album), 2025 album by Benjamin Booker * Lower (surname) * Lower Township, New Jersey *Lower Receiver (firearms) * Lower Wick Gloucestershire, England See also * Nizhny {{Disambiguation ...

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided b ...

of what is now

Victoria Victoria most commonly refers to: * Queen Victoria (1819–1901), Queen of the United Kingdom and Empress of India * Victoria (state), a state of Australia * Victoria, British Columbia, Canada, a provincial capital * Victoria, Seychelles, the capi ...

, Australia, known from single species ''P. selwyni''. This is the first

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

fossil vertebrate named from Victoria.

Classification

Due to the only known fossil of ''Psilichthys'' is incomplete holotype specimen, its classification is discussed for years. It was originally described as a possibly palaeoniscid or chondrosteid. It has also previously been referred to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Birgeriidae ''Birgeria'' is a genus of carnivorous marine Actinopterygii, ray-finned fish from the Triassic Period (geology), period. ''Birgeria'' had a global distribution, with fossil known from Madagascar, Spitsbergen, Germany, Switzerland, Italy, Sloveni ...

. Waldman (1971) denied interpretation as chondrosteid, considering the character that lacked scales which used to classify it as

acipenseriform Acipenseriformes is an order of basal ray-finned fishes that includes living and fossil sturgeons and paddlefishes (Acipenseroidei), as well as the extinct families Chondrosteidae and Peipiaosteidae. They are the second earliest divergin ...

, is misidentification and it preserved some of scales. Waldman suggested that is likely to be a palaeoniscid that belongs to Coccolepidae, although due to preservation it is tentative. It is not belong to birgeriid considering differences from ''

Birgeria ''Birgeria'' is a genus of carnivorous marine ray-finned fish from the Triassic period. ''Birgeria'' had a global distribution, with fossil known from Madagascar, Spitsbergen, Germany, Switzerland, Italy, Slovenia, China, Russia, Canada and Nev ...

''.Waldman, M., 1971, A re-examination of ''Psilichthys selwyni'' Hall, from the Lower Cretaceous of Victoria: Proceedings of the Royal Society of Victoria 84:263–265 However, if identification as acipenseriform is true, it would be the only member of that group known from the southern hemisphere.

References

{{palaeonisciformes-stub Prehistoric chondrostei