''Acronemus'' 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 euselachian shark from the Middle Triassic of

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

. It is an enigmatic genus of shark with uncertain relations to other sharks. Though originally placed within

Ctenacanthiformes Ctenacanthiformes is an extinct order of chondrichthyan fish. They possessed ornamented fin spines and cladodont dentition. Members of the family Ctenacanthidae may have survived into the Cretaceous based on teeth found in deep water deposits of ...

, it is now considered Euselachii '' incertae sedis'', due to its mixture of features similar to hybodontiforms and neoselachians. Originally, teeth from this genus were attributed to "''

Acrodus ''Acrodus'' (from el, άκρος , 'high' and el, ὀδούς 'tooth') is an extinct genus of cartilaginous fish from the Permian to Paleocene periods.Johnson, G., 1981. Hybondontoidei (Chondrichthyes) from the Witchita- Albany Group ( Early ...

bicarinatus''" while fin spines were named "''

Nemacanthus ''Nemacanthus'' (from el, νέμω , 'to distribute' and el, ἄκανθα , 'spine') is an extinct genus of prehistoric sharks in the family Palaeospinacidae. The species ''N. elegans'' is from the Triassic of Idaho, United States.H. M. Evans ...

tuberculatus''". Associated material showed they were the same animal, with the older specific epithet (''tuberculatus'') taking precedence. The shark was given the new genus ''Acrocnemus'', containing a single species (''A. tuberculatus''). ''Acronemus'' is found in the Anisian-age Grenzbitumenzone (also known as the

Besano Formation The Besano Formation is a geological formation in the southern Alps of northwestern Italy and southern Switzerland. This formation, a short but fossiliferous succession of dolomite and black shale, is famous for its preservation of Middle Triassic ...

) of Monte San Giorgio. It was a small shark measuring long.

References

Elasmobranchii Prehistoric shark genera {{Triassic-fish-stub