| Pleurotomarioidea | |
|---|---|
| A shell of Entemnotrochus rumphii | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| (unranked): | clade Vetigastropoda |
| Superfamily: | Pleurotomarioidea Swainson, 1840 |
| Families | |
|
See text |
|
Pleurotomarioidea is a superfamily of small to large marine gastropods included in the Vetigastropoda.[1]
These are the slit shells, originally named Pleurotomariacea, in keeping with the convention for naming superfamilies at the time.
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Forming the first evidence of crown-group gastropods when they appeared in the Upper Cambrian, the fossil record of the Pleurotomarioideans has no substantial gaps until today. The group took quite a hit at the K–T boundary, with only the Pleurotomariidae surviving the extinction – and then only in deep waters.[2]
Living representatives of the group were first discovered in the mid-19th century, and their unusual mix of primitive and derived characters perplexed biologists. The researchers originally responded by re-working their ideas of how the gastropod lineage evolved, but with the introduction of cladistics, attempts are currently underway to fit them into a molluscan phylogeny.[2]
J. D. Stilwell et al. 2004[3] put the Pleurotomarioidea in the order Archaeogastropoda which is included in the Prosobranchia.
The following families have been recognized in taxonomy by Tracey at al. (1993)[4] and in the taxonomy of Bouchet & Rocroi (2005):
(Families that are exclusively fossil are indicated with a dagger †)
Bouchet and Rocroi (2005) includes the Pleurotomarioidea in the Vetigastropoda, following Ponder and Lindberg (1997), but refers to the Vetigastropoda simply as a clade.
P. J. Wagner 2008[5] includes the superfamily Pleurotomarioidea, (ex Pleurotomariacea) in the suborder Pleurotomariina and superorder Vetigastropoda. This as yet (September 2010) unpublished opinion by Wagner.[5]