Guildayichthyidae

from Wikipedia, the free encyclopedia
Guildayichthyidae
Discoserra pectinodon

Discoserra pectinodon

Temporal occurrence
Mississippium (Lower Carboniferous)
359.2 to 318.1 million years
Locations
Systematics
Trunk : Chordates (chordata)
Sub-stem : Vertebrates (vertebrata)
Superclass : Jaw mouths (Gnathostomata)
Class : Ray fins (Actinopterygii)
Order : Guildayichthyiformes
Family : Guildayichthyidae
Scientific name of the  order
Guildayichthyiformes
Lund , 2000
Scientific name of the  family
Guildayichthyidae
Lund, 2000

The Guildayichthyidae are a family of bony fish in which two fossil species from the Bear Gulch limestone ( Mississippium of Montana ) are placed.

features

The two species Guildayichthys carnegiei and Discoserra pectinodon were sea-dwelling, high-backed fish with disc -shaped, laterally flattened and covered with large, rhombic ganoid scales .

Characteristic of the fish are some particularly large, strongly built bones in the middle of the skull, some of which were unpaired. The cheek region consisted of a multitude of different suborbital bones. The skull consisted of several independently ossified bones.

Its mouth was small, the premaxillary was in pairs and only loosely connected, and the maxillary did not extend further back than the middle of the orbit . Over the orbit they had two to three rows of paired bones. They also had more than one row of bones under the orbit. The number was variable within a species. The dorsal fin was long and low, its base was scaly, the caudal fin was heterocercous .

Systematics

When family and order were introduced in 2000, the American paleontologist Richard Lund assigned them to the cladistia subclass as a sister group of the recent pike-pike (Polypteridae) found in African freshwater . A short time later this view was revised and the Guildayichthyiformes were placed in a sister group relationship to the Tarrasiiformes on the basis of 20 characteristics .

literature

  • Richard Lund: The new Actinopterygian or Guildayichthyiformes from the Lower Carboniferous of Montana (USA). In: Geodiversitas. Vol. 22, No. 2, 2000, ISSN  1280-9659 pp. 171-206, (PDF; 717 kB) .

Individual evidence

  1. ^ Richard Cloutier & Gloria Arratia: Early diversification of actinopterygians. in Recent Advances in the Origin and Early Radiation of Vertebrates. G. Arratia, MVH Wilson & R. Cloutier (eds.): Pp. 217–270, © 2004 by Verlag Dr. Friedrich Pfeil, Munich, Germany - ISBN 3-89937-052-X

Web links