Tarrasiidae
Tarrasiidae | ||||||||||||
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Temporal occurrence | ||||||||||||
Viséum to Namurium (Lower Carboniferous) | ||||||||||||
345.3 to 316.5 million years | ||||||||||||
Locations | ||||||||||||
Systematics | ||||||||||||
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Scientific name of the order | ||||||||||||
Tarrasiiformes | ||||||||||||
Berg , 1940 | ||||||||||||
Scientific name of the family | ||||||||||||
Tarrasiidae | ||||||||||||
Woodward , 1891 |
The Tarrasiidae are an extinct bony fish family from the subclass of the cartilaginous organoids (Chondrostei). The group lived in the Lower Carboniferous.
features
The Tarrasiidae were ten to 13 centimeters long. Their body was elongated and resembled that of a fish larva or that of the pike ( Polypterus ). Their short skull resembled that of the Palaeonisciformes . Directly behind the head began a long dorsal fin, which formed a long, uninterrupted fin edge with the diphycerken caudal fin and the anal fin beginning approximately in the middle of the body. Under each fin ray of the dorsal fin there were two rows of fin supports (radialia), with the anal fin there was only one row. The small pectoral fins had eight radialia that sat directly on the shoulder girdle. Ventral fins were not present. All fin rays were undivided but articulated. The notochord has not regressed throughout life. Only the arches on the back and abdomen ossified.
Systematics
The Tarrasiidae are assigned by Joseph S. Nelson , the author of the standard work on fish systematics, to the subclass of cartilage organoids (chondrostei), to which the recent sturgeons also belong. A cladistic study came to the conclusion that they are the sister group of all ray fins with the exception of the Flössler (Polypteridae). The exact systematic position is shown in the following cladogram .
Bony fish |
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Genera
Two genera with numerous species have been described:
- Paratarrasius Traquair, 1881 (69 species)
- Tarrasius Lund & Melton, 1982 (ten species)
Tarrasius had a scaly body in front and scaly back, while Paratarrasius was completely scaly.
literature
- Joseph S. Nelson : Fishes of the World. 4th edition. John Wiley & Sons, Hoboken NJ 2006, ISBN 0-471-25031-7 .
- Arno Hermann Müller: Textbook of paleozoology. Volume 3: Vertebrates. Part 1: fish in the broader sense and amphibians. Gustav Fischer, Jena 1985.
supporting documents
- ^ Richard Lund, Cecile Poplin: Cladistic Analysis of the Relationships of the Tarrasids (Lower Carboniferous Actinopterygians). In: Journal of Vertebrate Paleontology. Vol. 22, No. 3, September 2002, pp. 480-486, doi : 10.1671 / 0272-4634 (2002) 022 [0480: CAOTRO] 2.0.CO; 2 .