Iniopterygiformes

Iniopterygia

  • North America, Europe, China

The Iniopterygia ( " neck -finned " ) constitute an extinct taxon of cartilaginous fish. The fossils of this group of cartilaginous fishes are known from the Palaeozoic and mainly from the upper Carboniferous ( Pennsylvanian ) of North America. Overall, the Iniopterygia but also found in Paleozoic sediments in Central Europe and China from the Devonian to the Permian.

Features

The Iniopterygia were about 50 cm long. Her head is large and short, dorsally usually scaly. important for the classification of cartilaginous fish are mainly the construction and arrangement of the teeth. They served at the Iniopterygia partly for grabs, partly (as plates; during Sibyrhynchidae ) for biting. The jaws are diamagnetic or connected holostyl with the skull. The gills are below the skull, gill cover ( with radii and cartilage plate ) may be present.

The shoulder girdle is wide anteriorly and directed the front of the branchial, dorsal it is narrower and extends right up to the back side. The pectoral fins are very highly inflected, cambered or wide; the pterygium is very large. The front beam is busy in males with thorny scales, the hull is otherwise unbeschuppt. The pelvic fins are fitted in the male with long Klaspern ( Mixipterygien, for internal fertilization ). The caudal fin is round or as in the chimaeras ( Chimaeroidea ) absent. The dorsal fin is located, if any, in the middle at the back. She has no fin spines.

Due to the density of that radiation, it is difficult at present, the systematic position of the Iniopterygier within the cartilaginous fish "somewhere between sharks and chimaeras " specify in more detail. Nelson assigns them to Holocephali; they are to be the sister group of all other Holocephali.

They apparently lived sociable surfaces and coastal and jumped ( in flight), perhaps from the water like the Exocoetidae, but some (like Cervifurca ) roche like in the benthic zone.

Genera

  • Family Iniopterygidae Cervifurca
  • Iniopteryx
  • Promyxele
  • Sibyrhynchus
Adaptive Radiation
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