Porolepiformes

Porolepiformes
Live reconstructions of different genera of the Porolepiformes
Temporal occurrence
Devon
400 to 360 million years
Systematics
Over trunk : Neumünder (Deuterostomia) Trunk : Chordates (chordata) Sub-stem : Vertebrates (vertebrata) Superclass : Jaw mouths (Gnathostomata) Class : Meat finisher (Sarcopterygii) Order : Porolepiformes
Scientific name
Porolepiformes
Jarvik , 1942

The Porolepiformes are an extinct group of bony fish from the class of the meat fin fish (Sarcopterygii). They lived in the Devonian , their fossil remains were mainly found in the freshwater deposits of the middle and upper Devonian.

features

The Porolepiformes had a plump body. Their pectoral fins were elongated and often sat relatively high on the trunk, the pelvic fins were short, the caudal fin heterocerk . Older forms had thick, rhombic cosmoid scales , younger ones had thin cycloid scales . They were relatively large predatory fish with wide skulls, small eyes and had specially folded dentin in their large fangs . Both outer nostrils were still there, Choanen (paired opening to the roof of the mouth) probably not. Judging by their body shape, they were stalkers , waiting for prey swimming close by, which they then caught with a sudden advance.

Systematics

Laccognathus embryi

• Porolepidae
  • Porolepis , Lower Devonian from Svalbard and Europe, 1.5 m long
• Holoptychiidae
  • Glyptolepis , Central Devon of East Greenland and Scotland, 1 m long
  • Duffichthys , Scotland
  • Holoptychius , Oberdevon, lived worldwide in fresh waters, up to 2 m long
  • Laccognathus , marin , Latvia

literature

• Joseph S. Nelson : Fishes of the World. John Wiley & Sons, 2006, ISBN 0-471-25031-7 .
• Kurt Fiedler: Textbook of Special Zoology. Volume 2: Part 2: Fish. Gustav Fischer, Jena 1991, ISBN 3-334-00339-6 .
• John A. Long: The Rise of Fishes. Johns Hopkins University Press, 1995, ISBN 0-8018-4992-6 .
• Hans-Peter Schultze: Fossil Sarcopterygii. In: Wilfried Westheide, Reinhard Rieger: Special Zoology Part 2: Vertebrae and Skull Animals. 1st edition. Spektrum Akademischer Verlag, Heidelberg / Berlin 2004, ISBN 3-8274-0307-3 , p. 301.
• Gael Clement: Evidence for lack of choanae in the Porolepiformes. In: Journal of Vertebrate Paleontology . 21, 2001, pp. 795-802.

Individual evidence

1. ^ Gael Clement: Evidence for lack of choanae in the Porolepiformes. In: Journal of Vertebrate Paleontology. 21, 2001, pp. 795-802.

Web links

Commons : Porolepiformes  - collection of images, videos and audio files

• Palæos Porolepiformes