Erismatopterus
extinct genus of fishes
Erismatopterus is an extinct genus of percopsiform fish which lived during the early to middle Eocene epoch and containing the single species Erismatopterus levatus. A report of the genus in sediments of similar age in Washington State have been discredited. Erismatopterus is treated as part of the family Percopsidae, but formerly was the type genus of the extinct family Erismatopteridae. The genus is closely related to Amphiplaga of related lake sediments. Shoaling behavior has been reported from a mass mortality fossil of E. levatus and attributed as a predator-evasion response behavior.
Distribution
Erismatopterus levatus is known from solitary fossils and mass mortality groups which are compression-impression fossils preserved in layers of soft sedimentary rock. Along with other well preserved fish fossils, the E. levatus specimens are found in several outcrops of the Early to Middle Eocene Green River Formations Lake Gosiute and Lake Uinta. The formation is a group of Late Paleocene to Late Eocene depositional basins in Wyoming, Colorado, and Utah. Of the three paleolakes that comprise the formation, E. levatus seems to have been absent from Fossil Lake. Study of the paleoflora preserved in the formation indicates the lake was around 1,500–2,900 metres (4,900–9,500 ft) in elevation surrounded by a tropical to subtropical environment that had a distinct dry season.
Begin with the source’s own compact description: “Erismatopterus” is extinct genus of fishes. The dossier treats that line as a proposition to test through Erismatopterus, extinct and genus, not as a finished interpretation.
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This entry incorporates text from “Erismatopterus” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.