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Archaeogastropoda
Archaeogastropoda (also known as Aspidobranchia) was a taxonomic order of sea snails used in older classifications of gastropods, i.e. snails and slugs. Archeogastropoda are marine prosobranch gastropod mollusks, mainly herbivores, typically having two gills and a double-chambered heart, with the eggs and sperm discharged directly into the water. They were traditionally regarded as a relatively primitive group. This older classification of the gastropods is based on the classification of Johannes Thiele (1925). This classification was not based on true phylogenetic relationships, but on more general affinities between the groups. In the last few years, two new cladistic taxonomies of the gastropods have been published (in 1997 and 2005). This has led to an extensive reclassification of gastropod taxa. The taxon Archaeogastropoda was found to be a paraphyletic group, and therefore unacceptable in a strictly cladistic classification. In the 1997 classification, most of the former ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleurotomariacea
Pleurotomariacea is one of two names that are used for a taxonomic superfamily of sea snails that are an ancient lineage and are well represented in the fossil record. The name Pleurotomariacea is used by paleontologists, who, because they usually have only the hard parts of mollusks to study, often use a slightly different scheme of classification from that used by scientists who study living mollusks. The name Pleurotomariacea is based on Swainson, 1840 (Pleurotomariae) and was described in 1960 in the Treatise on Invertebrate Paleontology, (I197)Treatise on Invertebrate Paleontology Part I, R.C. Moore (ed) Geol Soc of America and Univ. Kansas Press, 1960. The taxon was established for mostly conispiral, but also discoidal and auriform (ear-like) shells which have a nacreous, aragonite, inner layer. The Pleurotomariacea, now often seen as Pleurotomarioidea, has been included in the Archaegastropoda. although more recent classifications put it in a more restricted sense in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |