Bellerophon (genus)

from Wikipedia, the free encyclopedia
Bellerophon
Bellerophon fossil from the Museum Val Gardena in Ortisei in Val Gardena

Bellerophon fossil from the Museum Val Gardena in Ortisei in Val Gardena

Temporal occurrence
Cambrian to Lower Triassic
about 500 to 250 million years
Locations
Systematics
Primordial mouths (protostomia)
Molluscs (mollusca)
Snails (gastropoda)
Bellerophontida
Bellerophontidae
Bellerophon
Scientific name
Bellerophon
Montfort , 1808

Bellerophon is a genus of extinct snails from the Paleozoic and the early Lower Triassic of Central Europe and other parts of the world. This genus of early sea-dwelling molluscs (Mollusca) is named after the legendary figure Bellerophon from Greek mythology.

features

The housing of Bellerophon is rolled spirally, the diameter of the housing aperture increases from inside to outside rapidly. The casing is rolled up in one plane, so it does not form a tip (apex) as is the case with many recent snail species. The surface of the housing is smooth, only the individual growth lines can be seen. Outwardly, the snail shell is similar to the shell of the pearl boats (nautiloids), which, however, belong to the cephalopods and have housings inside with chambers.

Bellerophon enclosures can be up to 50 centimeters in size. There is often a mark on the outside that divides the housing into an upper and a lower half. It is therefore believed that part of the mantle and foot of the snail covered the lower part of the housing.

Linsley suspects that these snails could move relatively quickly and retreat completely into the housing in case of danger.

distribution

The genus is known worldwide from Paleozoic layers since the late Cambrian ( Furongian ). Most of the species have been found between the middle Ordovician and the end of the Silurian . Bellerophon became extinct in the early Triassic . Species that have survived across the border between the Paleozoic and Mesozoic Era can be used to study the mass extinction at the end of the Permian .

Systematics

Although the majority of paleontologists consider Bellerophon to be a primitive snail, there are some scientists who suspect a more native group of molluscs behind this genus. However, the genus Bellerophon is said to have already had a twisted viscera like the other groups of snails. From the symmetry of their housing it can be concluded that most of the organs were still bilaterally symmetrical.

Types (selection)

Individual evidence

  1. ^ RM Linsley: Locomotion rates and shell form in the gastropoda. In: Malacologia. 17, pp. 193-206, 1978, p. 201.

literature

  • JB Knight, LR Cox, AM Keen, RL Batten, EL Yochelson, R. Robertson: Systematic descriptions [Archaeogastropoda]. In RC Moore . (Ed.): Treatise on Invertebrate Paleontology. Part I. Mollusca 1, Geological Society of America and Kansas University Press, Colorado and Kansas, 1960.
  • RC Moore, CG Lalicker, AG Fischer: Invertebrate Fossils. McGraw Hill Book Company, New York, 1952.
  • PJ Wagner: Gastropod phylogenetics: progress, problems and implications. In: Journal of Paleontology. 75, pp. 1128-1140, 2001.

Web links