Powichthys

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Powichthys
Temporal occurrence
Lochkovian (Lower Devonian)
419.2 to 410.8 million years
Locations
Systematics
Trunk : Chordates (chordata)
Sub-stem : Vertebrates (vertebrata)
Superclass : Jaw mouths (Gnathostomata)
Class : Meat finisher (Sarcopterygii)
Rhipidistia
Genre : Powichthys
Scientific name
Powichthys
Jessen , 1975

Powichthys is an extinct genus of fish from the class of the meat fin (Sarcopterygii), whichoccurredin the Lower Devonian ( Lochkovium ). Fossils of the genus, which are assigned to two species, have been found on Prince of Wales Island in the Canadian Arctic and on Svalbard . Powichthys is the only basal sarcopterygian from the Lochkovium that has so far been found outside of China. The name Powichthys was composed of the abbreviation POW for Prince of Wales Island and the Greek word for fish ("ichthys").

features

Powichthys was a small predatory fish and stayed smaller than 30 cm. The genus is best known for its skull fossils. The skull bones were heavy and thick, the body covered with thick, rhombic scales. The eyes were small, to compensate for this the sideline system was well developed. Rows of small bones surrounded the most important paired skull bones, a feature also found in lungfish (Dipnoi). The sutures were always visible between the premaxillary and the head shield formed from the frontal bone and ethmoid . The frontal bone was long and the parietal was short. The neurocranium was not completely divided into two sections, as is the case with the coelacanth . Odontodes lay within the cosmoid scales . The pores of the scales were lined with an enameloid layer, a substance similar to tooth enamel , a feature that Powichthys shares with the Porolepiformes , but which does not appear in any other group of meatfinchers.

species

  • Powichthys spitsbergensis , Clément & Janvier 2004; Spitsbergen
  • Powichthys thorsteinssoni , Jessen, 1975; Prince of Wales Island

Systematics

Powichthys is assigned to the Rhipidistia , the meat-finisher group to which the lungfish also belong, and from which the land vertebrates ultimately emerged. Within the Rhipidistia they are the sister group of the Porolepiformes.

literature

  • John A. Long: The Rise of Fishes . The Johns Hopkins University Press, 1995, ISBN 0801849926

Individual evidence

  1. ^ Long (1995), pp. 185-186.

Web links