Search results
Results from the WOW.Com Content Network
[11] [12] The total number of living species of freshwater snails is about 4,000. [13] Recently extinct species of gastropods (extinct since 1500) number 444, 18 species are now extinct in the wild (but still exist in captivity), and 69 species are "possibly extinct". [14] The number of prehistoric (fossil) species of gastropods is at least ...
It is claimed to be the oldest animal fossil, being found in rock aged between 760 and 550 million years ago. The genus was named after the Otavi Group in Namibia in which the fossils were found. The oldest fossils are from the Tonian period, before the Cryogenian glaciations, but the latest found were from the Nama Group rocks, which are from ...
Turritella agate, in which the fossils are a different genus. One variety of "Turritella agate", that from the Green River Formation in Wyoming, is a fossiliferous rock which does indeed contain numerous high-spired snail shells.
This list of marine gastropod genera in the fossil record is an attempt to list all the genera of sea snails or marine gastropod mollusks which have been found in the fossil record. Nearly all of these are genera of shelled forms, since it is relatively rare for gastropods without a shell ( sea slugs ) to leave any recognizable traces.
This genus is known in the fossil records from the Cretaceous to the Quaternary (age range: from 125.45 to 0.0 million years ago). Fossils of species within this genus have been found all over the world. There are about 25 known extinct species. [4] Murex altispira Fossil shell of Murex spinicosta from Pliocene of Italy
Ammonoids are excellent index fossils, and they have been frequently used to link rock layers in which a particular species or genus is found to specific geologic time periods. Their fossil shells usually take the form of planispirals , although some helically spiraled and nonspiraled forms (known as heteromorphs ) have been found, primarily ...
The oldest fossil cerionid is C. acherontis from the Upper Cretaceous Hell Creek Formation, in Montana, northwestern USA. [5] The second oldest record is the genus Brasilennea from the Brazilian Paleocene Itaboraí Basin , in Rio de Janeiro.
Elimia tenera, formerly known as Goniobasis tenera, is an extinct species of freshwater snail with an operculum, in the aquatic gastropod mollusk family Pleuroceridae. [1] This species flourished during the Eocene and is now known only from the fossil record. The genus name Elimia was restored to this species in 1975; [2] formerly it was placed ...