Bellerophon (mollusc)
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| Bellerophon Fossil range: Silurian-Early Triassic |
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Bellerophon is a genus of extinct, mostly Paleozoic sea snail. These are fossil marine gastropod molluscs in the order Bellerophontida. The genus was named after Bellerophon, the ancient Greek hero.
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[edit] Shell description
The genus is characterised by a shell which is globose, convolute, and planispiral (symmetrically coiled). The shell of Bellerophon superficially resembles that of a miniature cephalopod (e.g. Nautilus or an ammonite), except that septa are lacking.
The shell of Bellerophon is often a couple of centimeters in maximum dimension. The external surface is smooth, ornamented only by growth lines. There is a low crest or ridge running along the midline of the shell.
Many specimens of Bellerophon show something resembling a "waterline" about half-way up the shell, suggesting that a large amount of the mantle and foot were exposed and covered the outside of the shell, as in the extant Cypraeidae and Naticidae.
[edit] Possible life habits
These animals were probably quick moving, relying on speed to avoid predators and, when this was not possible, withdrawing deeply into the shell. (Linsley 1978 p.201)
[edit] Range of distribution
The genus occurs world-wide, and is known from the Silurian to the Early Triassic periods. (Knight et al 1960)
[edit] Discussion of the taxonomy
Although usually classified as a primitive gastropod, there is a minority view that the Bellerophontida actually represented a more primitive, untorted type of mollusk, (see Torsion) which evolved a spiral shell independently. Another view is that some Bellerophontids, including Bellerophon, were torted gastropods, but that others were untorted forms. (Wagner, 2001 p.1130)
[edit] Species within the genus Bellerophon
- B. vasulites Montfort - the type species, from the Middle Devonian of Germany
- B. graphicus Moore from the late Pennsylvanian (Virgilian) of Kansas
- B. regularis (Waagen) from the Permian of India
- ...
[edit] References
- Knight, J. B., Cox, L. R., Keen, A. M., Batten, R. L., Yochelson, E. L., and Robertson, R. (1960). Systematic descriptions [Archaeogastropoda]. In Moore, R. C. (ed.) Treatise on Invertebrate Paleontology. Part I. Mollusca 1, Geological Society of America and Kansas University Press, Colorado and Kansas.
- Linsley, R. M. 1978. Locomotion rates and shell form in the gastropoda. Malacologia 17, 193-206
- Moore, R.C., Lalicker, C.G., and Fischer, A. G., 1952, Invertebrate Fossils, McGraw Hill Book Company, New York; 766 pp.
- Wagner, P. J. 2001 Gastropod phylogenetics: progress, problems and implications. Journal of Paleontology 75: 1128 - 1140
[edit] External links
- Bellerophontida - Palaeos
