Parasemionotidae

Parasemionotidae
Parasemionotus in the Museo Civico di Storia Naturale di Milano
Temporal occurrence
Triad
249.7 to 228 million years
Locations
Australia, China, Europe, Greenland, Madagascar & North America.
Systematics
Class : Ray fins (Actinopterygii) Subclass : Neuflosser (Neopterygii) Subclass : Bone organoids (holostei) Halecomorphi Order : Parasemionotiformes Family : Parasemionotidae
Scientific name of the  order
Parasemionotiformes
Lehman , 1966
Scientific name of the  family
Parasemionotidae
Stensio , 1932

The Parasemionotidae ( Gr .: παρά, "para" = next to, + Semionotidae ) are a family of extinct, primeval bony fish . Over a dozen genera from the lower and middle Triassic are known. Fossils from marine deposits were found mainly in East Greenland and Madagascar.

features

The Parasemionotidae are more developed than the cartilage organoids (Chondrostei), but originally compared to other new fins (Neopterygii).

A common feature is the oval preoperculum ( front gill cover), which is often indented ventrally . The maxillary is indented concave at the rear edge. Their teeth are fine behind and thicker in front. The caudal fin is supported by 22 to 25 main fin rays.

Since the cheek region of the Parasemionotidae is ossified completely differently, it may be a collection of not closely related forms that are only at the same stage of development. The ancestors of the Pholidophoriformes and the Amiiformes could be found among them .

External system

The Parasemionotidae are the only family of the order Parasemionotiformes.

Genera

• Albertonia
• Broughia
• Devillersia
• Helmolepis
• Icarealcyon
• Jacobulus
• Lehmanotus
• Ospia
• Parasemionotus
• Piveteaunotus
• Praesemionotus
• Promecosomina
• Stensionotus
• Thomasinotus
• Watsonulus

literature

• Robert L. Carroll : Paleontology and Evolution of the Vertebrates. Thieme, Stuttgart et al. 1993, ISBN 3-13-774401-6 .
• Joseph S. Nelson : Fishes of the World. 4th edition. John Wiley & Sons, Hoboken NJ 2006, ISBN 0-471-25031-7 .
• Melanie LJ Stiassny, Lynne R. Parenti, G. David Johnson (Eds.): Interrelationships of Fishes. Academic Press, San Diego CA et al. 1996, ISBN 0-12-670950-5 , Google Books .

Web links

Commons : Parasemionotidae  - Collection of images, videos and audio files

• The Paleobiology Database: Parasemionotidae
• Palaeos: Parasemionotidae