Aspidoceras
Aspidoceras is an extinct ammonoid cephalopod genus belonging to the family Aspidoceratidae. [2]
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| Fossil shell of Aspidoceras acanthicum from Jurassic of Madagascar | |
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| Genus: | Aspidoceras Zidttel, 1868 |
Taxonomy
Aspidoceras, named by Zittel, 1868, is the type genus for the persphictacian family Aspidoceratidae and subfamily Aspidoceratinae in which it is included. It is considered related to genera like Chinamecaceras, Cubaspidoceras, Euaspidoceras, Extranodites, Intranodites, Neaspidoceras, Oligopsychopsis, Orthaspidoceras, Schaireria and Simaspidoceras.[3]
Selected species
- † Aspidoceras argobbae Dacque 1905
- † Aspidoceras catalaunicum Loriol 1872
- † Aspidoceras somalicum Dacque 1905
- † Aspidoceras supraspinosum Dacque 1905
Fossil record
Aspidoceras mainly lived during the Late Jurassic (Oxfordian) until Cretaceous (Berriasian), with a fairly broad distribution. Fossils have been found in Italy, Chile, Spain, Algeria, Antarctica, Argentina, Ethiopia, France, Germany, Hungary, India, Iran, Madagascar, Portugal, Romania, Russia, Somalia, Switzerland, the United Kingdom, United States and Canada.[3]
Description
Aspidoceras has an evolute shell with quadrate-rounded or depressed whorls that have two rows of tubercles, the outer near the middle of the whorl sides. The outer row soon fades in many species. Some species are also ribbed. The venter, or outer rim, is generally wide and broadly arched. Aspidoceras was predated by Euaspidoceras, possibly its ancestor. [4]
References
- Sepkoski, Jack (2002). "A compendium of fossil marine animal genera (Cephalopoda entry)". Bulletins of American Paleontology. 363: 1–560. Archived from the original on 2016-02-25. Retrieved 2017-10-18.
- Mikko's Phylogeny Archive: Ammonitida
- Paleobiology Database
- Crioceratites.free (in French)
Further reading
- Arkell, et al.,1957. Mesozoic Ammonoidea; Treatise on Invertebrate Paleontology, Part L (Ammonoidea). Geol Soc of America and Univ Kansas Press. p. L338-339.