Menaspidae
| Menaspidae | ||||||||||||
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Menaspis armata and Deltoptychius , two Menaspidae |
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| Temporal occurrence | ||||||||||||
| Mississippian to Permian Triassic border | ||||||||||||
| 340 to 254 million years | ||||||||||||
| Locations | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Menaspidae | ||||||||||||
| Woodward , 1891 |
The Menaspidae form an extinct family of cartilaginous fish , by the Lower Carboniferous to Permian inventory had.
Taxonomy
According to Carroll (1988), the Menaspidae family (rarely Menaspididae ) belonging to the order Menaspiformes includes the two genera Menaspis and Deltoptychius . In the Fossilworks database , however, Deltoptychius is assigned to its own family, the Deltoptychiidae . This post follows Caroll's example.
The exact taxonomic assignment of the Menaspidae is difficult and controversial. For example, Ortlam does not see any cartilaginous fish in Menaspis , but an arctolepid Arthrodira . If this were to be the case, this ancient family would have continued into Zechstein 1 ( copper slate ).
features
In their dentition the Menaspidae are very similar to the Chimaeriformes , but otherwise show very different characteristics. Your body is flattened dorsoventrally. Dorsal fins are absent. Behind the top of the head, the animals have a skin armor (roughly comparable to that of the Placodermi / Arthrodira ), which is reinforced with very small conical appendages. The skin armor has a pair of wing-like extensions at its front end. In Menaspis there are three pairs of backwardly curved spinous processes ( English cephalic spines ), which probably had defensive tasks. In addition to the skin armor, the animals are covered by overlapping scales, which are arranged in a rather complicated pattern. Two rows of very large scales run across the back. The individual scales have a cyclomorial structure.
Note: There are clear differences in the interpretation of the wing and thorn processes. These are based on the difficulty of determining the correct position of the fossil (whether it is on the underside or on the top).
Way of life
The Menaspidae were quite small, nectobenthic animals (in free water close to the ground); Menaspis, for example, did not grow larger than 25 centimeters. They probably stayed in not too great a depth, chasing after small vertebrates.
Occurrence
literature
- Bendix-Almgreen, SE: The anatomy of Menaspis armata and the phyletic affinities of the menaspid bradydonts . In: Lethaia . tape 4 , 1971, p. 21-49 .
- Carroll, Robert L .: Vertebrate Paleontology and Evolution . WH Freeman and Company, New York 1988, ISBN 0-7167-1822-7 .
- Hartmut Haubold and Günther Schaumberg: The fossils of copper slate . Wittenberg 1985.
- Josef Paul: The copper slate: lithology, stratigraphy, facies and metallogenesis of a black slate . In: Journal of the German Geological Society . tape 157 (1) , 2006, pp. 57-76 .
- Stahl, B .: Chondrichthyes III. In: HP Schultze and P. Kuhn (Eds.): Handbook of Palaeoichthyology . Vol. 4 Holocephali. Gustav Fischer Verlag, Stuttgart - New York 1999, p. 164 .
- Zangerl, R .: Chondrichthyes I. Paleozoic elasmobranchs . In: HP Schultze (Ed.): Handbook of Paleoichthyology . Vol. 3 Elasmobranchi. Gustav Fischer Verlag, Stuttgart 1981.
Individual evidence
- ↑ a b Ortlam, D .: New aspects for the interpretation of Menaspis armata Ewald (Kupferschiefer, Zechstein 1, Germany) with the help of stereoscopic X-ray technology . In: Geological Yearbook . A 81, 1986, p. 3-57 .
- ^ Patterson, C .: The philogeny of the chimaeroids . In: Phil. Trans. Roy. Soc. London . B 249, 1965, p. 101-219 .
- ↑ Friedrich Bachmayer and Erich Malzahn: The first evidence of a decapod cancer in the Lower Rhine copper schist . In: Ann. Naturhist. Mus. Vienna . 85 / A. Vienna 1983, p. 99-106 .