Hiodontiformes

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Hiodontiformes
A 48.5 million year old fossil of Hiodon woodruffi from the Klondike Mountain Formation in Washington, USA.

A 48.5 million year old fossil of Hiodon woodruffi from the Klondike Mountain Formation in Washington, USA.

Temporal occurrence
Albium (Lower Cretaceous) to this day
112.9 to 0 million years
Locations
  • North America
  • China
Systematics
Superclass : Jaw mouths (Gnathostomata)
Class : Ray fins (Actinopterygii)
Subclass : Neuflosser (Neopterygii)
Subclass : Real bony fish (Teleostei)
Overcohort : Osteoglossomorpha (Osteoglossomorpha)
Order : Hiodontiformes
Scientific name
Hiodontiformes
McAllister , 1968

The Hiodontiformes are an order of the real bony fish (Teleostei) which today is only represented by two species from the rivers and lakes of North America east of the Rocky Mountains , but in the Cretaceous and Tertiary periods they spread across the northern hemisphere and also in the western North America, as well as in East Asia.

features

The recent Hiodontiformes are herring-like fish that are about half a meter long. All Hiodontiformes show the following diagnostic synapomorphies :

The hyomandibular is two-headed. A special skin bone ("dermosphenotic bone"), which lies on the top of the head behind the eye sockets, is Y-shaped. The operculum ( gill cover bone ) has the shape of an irregular parallelogram . The upper arm of the post temporale is more than twice as long as the lower. The pelvic fins are supported by seven fin rays.

Genera

  • † Plesiolycoptera (early Upper Cretaceous, northeastern China)
  • † Yanbiania (Lower Cretaceous, northeastern China)
  • Family Hiodontidae

literature

Web links

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