Lophosteidae
| Lophosteidae | ||||||||||||||
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Obsolete systematic group The taxon dealt with here is not part of the systematics presented in the German-language Wikipedia. More information can be found in the article text. |
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| Temporal occurrence | ||||||||||||||
| late Silurian to lower Devonian | ||||||||||||||
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| Systematics | ||||||||||||||
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| Scientific name of the order | ||||||||||||||
| Lophosteiformes | ||||||||||||||
| Gross , 1969 | ||||||||||||||
| Scientific name of the family | ||||||||||||||
| Lophosteidae | ||||||||||||||
| Gross, 1969 | ||||||||||||||
The Lophosteidae family and the monotypical order Lophosteiformes summarize fragmentary fish fossils that were found on the Estonian island of Saaremaa in the Baltic Sea and in Australia. The Saaremaa finds are the earliest fossils of bony fish known to date. They come from the late Silurian . It is just isolated teeth, scales and individual bones.
features
The teeth are conical with a large central cavity. They lack the detached enameloid tooth caps (acrodin) that occur in the teeth of almost all radiation fins (actinopterygii). Possibly they sat directly on the jawbone without a tooth root.
The scales are rectangular or rhombic. They lack the ganoin layer , an enamel-like substance that covers the scales ( ganoid scales ) of later primitive ray fins as an iridescent, shiny, thick coating .
The cleithrum (part of the shoulder girdle ), only a partially preserved one is known, is similar to that of Cheirolepis , an early ray- finned fish.
Systematics
Two genera have been described from the scanty remains, Andreolepis and Lophosteus . Since no cohesive fish remains or intact fish have yet been found, it cannot yet be decided whether the Lophosteiformes can be assigned to the ray fins or the meat fins (Sarcopterygii). In the latest edition of Fishes of the World , a standard work on fish systematics, the taxon is no longer used.
literature
- Carole J. Burrow: A new lophosteiform (Osteichthyes) from the Lower Devonian of Australia. In: Geobios. Vol. 28, Supplement 2, 1995, ISSN 0016-6995 , pp. 327-333, doi : 10.1016 / S0016-6995 (95) 80134-0 .
- Walter Gross: Lophosteus superbus Pander, a teleostome from the Silurian Oesels. Lethaia , Volume 4, Issue 2, pages 131–152, April 1971, DOI: 10.1111 / j.1502-3931.1969.tb01249.x
- John A. Long: The Rise of Fishes. 500 Million Years of Evolution. The Johns Hopkins University Press, Baltimore MD et al. 1995, ISBN 0-8018-4992-6 .
- Joseph S. Nelson, Terry C. Grande, Mark VH Wilson: Fishes of the World. Wiley, Hoboken, New Jersey, 2016, ISBN 978-1118342336