''Pseudoasthenocormus'' is an extinct genus of

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or h ...

belonging to the family

Pachycormidae Pachycormiformes is an extinct order of marine ray-finned fish known from the Early Jurassic to the end of the Cretaceous. It only includes a single family, Pachycormidae. They were characterized by having serrated pectoral fins (though more rece ...

. It contains one species, ''P. retrodorsalis''. It lived during the upper

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

(

Kimmeridgian In the geologic timescale, the Kimmeridgian is an age in the Late Jurassic Epoch and a stage in the Upper Jurassic Series. It spans the time between 157.3 ± 1.0 Ma and 152.1 ± 0.9 Ma (million years ago). The Kimmeridgian follows the Oxford ...

– Tithonian, about 152–148 million years ago) and its fossil remains have been found in

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

.Eastman, C. R. (1914). Catalog of the fossil fishes in the Carnegie Museum. Memoirs of the Carnegie Museum. Vol. VI. No. 7.

Description

Large in size, this fish easily exceeded one metre in length. Like many other similar genera, ''Pseudoasthenocormus'' possessed a robust and compact body, although generally more slender than '' Asthenocormus''. As indicated by the specific epithet, the dorsal fin is set back, originating just behind the anal, and is much shorter than the latter. The dorsal fin is composed of a few rays, which decrease in size posteriorly. The anal fin has become independent, with the rays (about 30) starting almost vertically from the haemal arches. The palate was equipped with small, slightly curved conical teeth. Along the anterior margin of the jaws were larger teeth with laterally compressed bases.

Etymology

The generic name is derived from '' Asthenocormus'', and the specific epithet is after the Greek for "rear fin."

Classification

The first fossils of this animal, found in the famous Solnhofen deposit, were described in

1914 This year saw the beginning of what became known as World War I, after Archduke Franz Ferdinand of Austria, heir to the Austrian throne was Assassination of Archduke Franz Ferdinand, assassinated by Serbian nationalist Gavrilo Princip. It als ...

by Eastman, who attributed them to a new species of the genus ''Asthenocormus'' (''A. retrodorsalis''). It was only in 1999 that Lambers redescribed the species, attributing it to a separate genus (''Pseudoasthenocormus'').Lambers, P. H. (1999). The actinopterygian fish fauna of the Late Kimmeridgian and Early Tithonian 'Plattenkalke' near Solnhofen (Bavaria, Germany): state of the art. Geologie en Mijnbouw 78:215-229. This animal, as well as the related ''Asthenocormus'', was a large representative of the family Pachycormidae, a group of bony fishes close to the origin of the

teleosts Teleostei (; Greek ''teleios'' "complete" + ''osteon'' "bone"), members of which are known as teleosts ), is, by far, the largest infraclass in the class Actinopterygii, the ray-finned fishes, containing 96% of all extant species of fish. Teleo ...

and including some of the oldest filter-feeding fishes.

References

{{Taxonbar, from=Q30893126 Pachycormiformes Prehistoric ray-finned fish genera Late Jurassic fish Jurassic fish of Europe