''Monopteros'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

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 marine

bonytongue Osteoglossidae is a family of large-sized freshwater fish, which includes the arowanas. They are commonly known as bonytongues. The family has been regarded as containing two extant subfamilies Arapaiminae and Osteoglossinae, with a total of fiv ...

fish known from the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

. It contains a single species, ''M. gigas'', known from the

Early Eocene In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by th ...

Monte Bolca Monte Bolca is an Ypresian, Early Eocene-aged geologic site located near Verona, Italy, Verona, Italy. A ''Konservat-Lagerstätte'', it contains an extremely well-preserved and diverse marine biota, including the most diverse fish fauna of any Ce ...

, Italy. Its genus name, ''Monopteros'' meaning "one wing", comes from its large, elongated pectoral fins. The species name, ''gigas'', refers to its relatively large size at in length. It is thought to be a member of the extinct subfamily Phareodontinae, or at least closely related to it. Some earlier authorities erroneously placed it as a species of the late-surviving crossognathiform '' Platinx'', which it co-occurred with.

References

{{Taxonbar, from=Q56325022 Prehistoric ray-finned fish genera Osteoglossidae Eocene fish of Europe Ypresian genera Fossils of Italy Fossil taxa described in 1796