Sphenocephalus

Fossil of Sphenocephalus fissicaudus in Teylers Museum in Haarlem

• Europe

Sphenocephalus is an extinct genus of fish that lived during the Late Cretaceous. Fossils of single species, Sphenocephalus fissicaudus were found, among other things in Münsterland Baumberger calcareous sandstone in Europe. She lived prey on small animals.

Features

Sphenocephalus was a small, just over 10 cm long expectant freshwater fish with a laterally compressed shape, wide head and big eyes. The mouth opening was excessively long and reached up under her eyes. Characteristic was a horn -like sting on the back of the head. The only dorsal fin sat about on the middle of the body, started high and fell to the rear. The same form had the later -faceted anal fin. The pectoral fins were unusually small, the ventral fins were far ahead. The caudal fin was moderately indented. An adipose fin is absent.

As the recent, and possibly related with Sphenocephalus North American perch salmon ( Percopsidae ) shows Sphenocephalus a mixture of primitive and advanced features. With regard to the skull morphology Sphenocephalus is less derived than the perch salmon.

System

The systematic position of Sphenocephalus is uncertain due to its mosaic features. The genus is now placed as the sole representative in the so monotypic family Sphenocephalidae. Robert L. Carroll and Charles Albert Frick Hinger refer the family to the order of salmon -like grouper ( Percopsiformes ) within the paraphyletic superorder Paracanthopterygii. Carroll also noted similarities with the mucus -like head ( Beryciformes ).

The American ichthyologist Don roses and paleontologist Colin Patterson put the Sphenocephalidae in the monotypic order Sphenocephaliformes within the Paracanthopterygii, where it forms a sister group to the Anacanthines, a clade from all other Paracanthopterygii except Sphenocephaliformes and Percopsiformes. As common features of Sphenocephaliformes and Anacanthines a notch in the premaxilla and some characteristics of the first five vertebrae are called. Joseph S. Nelson, author of the standard work on fish systematics Fishes of the World, takes over this systematic classification. Jack Sepkoski holds Sphenocephalus for the first perch genera and assigns them the Perciformes ( Perciformes ) to.