Pachycormus
Pachycormus | ||||||||||||
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Pachycormus bollensis |
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Temporal occurrence | ||||||||||||
Lower Jurassic | ||||||||||||
182.7 to 174.1 million years | ||||||||||||
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Systematics | ||||||||||||
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Scientific name | ||||||||||||
Pachycormus | ||||||||||||
Agassiz , 1833 |
Pachycormus is a genus of extinct marine bony fish from the Lower Jurassic of Europe. Louis Agassiz establishes the genus in 1833. It is the type of the family Pachycormidae .
features
Pachycormus belongs to the Pachycormiformes, an extinct order of the ray fins (Actinopterygii). Its body is spindle-shaped and robust. Further features are the absence of the pelvic fins and the position of the unpaired fins (the dorsal fin lies completely in front of the anal fin). On the front part of the skull there is a concise fronto parietal bulge. Pachycormus could reach a length of over a meter.
Way of life
Due to the densely toothed, individual row of teeth and the needle-like small teeth, it is assumed that Pachycormus ate fish . Even cephalopods part of his diet. A strong homocercial caudal fin enabled it to swim quickly in deep waters.
Systematics
Pachycormus belongs to the family of the Pachycormidae and thus to the bony fish (Osteichthyes), but not to the real bony fish (Teleostei).
List of known species
- Pachycormus acutirostris (Agassiz, 1844)
- Pachycormus bollensis ( Quenstedt , 1858)
- Pachycormus curtus (Agassiz, 1843)
- Pachycormus elongatus (Sauvage, 1875)
- Pachycormus intermedius (Agassiz, 1844)
- Pachycormus macropterus ( De Blainville , 1818)
literature
- PH Lambers: On the Ichthyofauna of the Solnhofen Lithographic Limestone (Upper Jurassic, Germany). Rijksuniversiteit Groningen, 1992, OCLC 311805060 .
- M. Lindkvist: A Phylogenetic Appraisal of Pachycormus bollensis: Implications for Pachycormiform Evolution. Uppsala universitet, Institutions for Geovetenskaper Candidate Examination i Geovetenskap, 2012. (diva-portal.org)
- AJ Mainwaring: Anatomical and systematic review of the Pachycormidae, a family of Mesozoic fossil fishes. University of London, 1978, OCLC 500512214 , p. 87.
- AS Woodward: Catalog of the fossil fishes in the British Museum (Natural History), Cromwell Road, SW Part III. Containing the Actinopterygian teleostomi of the orders Chondrostei (concluded), Protospondyli, Aetheospondyli, and Isospondyli (in part). Family Pachycormidae. 1895, OCLC 769911406 , p. 385.
Individual evidence
- ↑ a b c P. Lambers: On the Ichthyofauna of the Solnhofen Lithographic Limestone (Upper Jurassic, Germany). Rijksuniversiteit Groningen, 1992, p. 233, p. 235.
- ↑ JP Lehman: Traité de Paléontologie Tome IV en trois volumes - L'Origine des Vertébrés leur expansion dans les eaux douces et le milieu marin - Actinoptérygiens, Crossoptérygiens, Dipneustes , 1966, p. 150.
- Jump up ↑ AJ Mainwaring: Anatomical and systematic review of the Pachycormidae, a family of Mesozoic fossil fishes. 1978, p. 87.
- ↑ M. Lindkvist: A Phylogenetic Appraisal of Pachycormus bollensis: Implications for Pachycormiform Evolution. Uppsala universitet, Institutions for Geovetenskaper Candidate Examination i Geovetenskap, 2012, p. 1.