The type species was described by
Edward Drinker Cope (1870) as
Cyprinodon levatus, and considered a species of
pupfish. The placement was revised a year later when he described the genus
Erismatopterus with
Erismatopterus rickseckeri as the type species, and
E. levatus moved into the genus as a second species. In 1877 a third species
Erismatopterus endlichi was also described by
Edward Drinker Cope, and the genus was considered to have three species though the 1960s. Review of the genus by ichthyologists
Donn Eric Rosen and
Colin Patterson (1969) however resulted in several changes, notably that
E. endlichi was deemed a
junior synonym of
Amphiplaga brachyptera and
E. rickseckeri a jr synonym of
E. levatus, leaving
Erismatopterus monotypic.
Etymology Lance Grande (1984) suggested the genus name to be derived the
Greek word
erisma meaning "cause of dispute",
top meaning "place" and
ter meaning
wonder. Grande notes that while Cope did not provide an etymological explanation for the name, it may have been a reference to Cope's difficulty in classification of the fossils.
Phylogeny Erismatopterus is placed in the
Paracanthopterygii family Percopsidae and phylogenetic analysis by Borden
et al (2013) placed it as a sister genus to †
Amphiplaga which is only found in
Fossil Lake.
Erismatopterus and
Amphiplaga have been considered closely allied genera since the early 1900s, so much so that
David Starr Jordan (1905) placed them into a separate family
Erismatopteridae. This placement was challenged by Rosen and Patterson who deemed the differences found by Jordan insufficient reason to segregate the genera into a stand-alone family. Rosen and Patterson chose to include both in an expanded Percopsidae. }} }} ''native east of the Rocky Mountains ==Description==