Pleurotomarioidea is a
superfamily of small to large
marine gastropod
Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda ().
This class comprises snails and slugs from saltwater, freshwater, and fro ...
s included in the order Pleurotomariida of the subclass
Vetigastropoda.
These are the slit shells, originally named
Pleurotomariacea, in keeping with the convention for naming superfamilies at the time. This updated version of the name for the taxon is usually used by students of the living Mollusca.
Paleontologists often still use the name
Pleurotomariacea instead.
Evolutionary history
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
Cretaceous–Paleogene boundary (K–T boundary), with only the Pleurotomariidae surviving the
Cretaceous–Paleogene extinction event – and then only in deep waters.
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
Cladistics ( ; from Ancient Greek 'branch') is an approach to Taxonomy (biology), biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesiz ...
, attempts are currently underway to fit them into a molluscan phylogeny.
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Taxonomy
2004 taxonomy
J. D. Stilwell et al. 2004 Classification of J. D. Stilwell et al. 2004
J. D. Stilwell, W. J. Zinsmeister, and A. E. Oleinik. 2004. Early Paleocene Mollusks of Antarctica: Systematics, Paleoecology and Paleobiogeographic Significance. Bulletins of American Paleontology 367 put the Pleurotomarioidea in the order
Archaeogastropoda which is included in the
Prosobranchia
Prosobranchia was a large Taxonomy (biology), taxonomic Class (biology), subclass of sea snails, land snails and freshwater snails. This taxon of gastropods dates back to the 1920s. It has however been proven to be polyphyly, polyphyletic (consis ...
.
1993 and 2005 taxonomy
The following families have been recognized in taxonomy by Tracey at al. (1993)
and in
the taxonomy of Bouchet & Rocroi (2005):
* family
Pleurotomariidae
* † family
Catantostomatidae
* † family
Kittlidiscidae
* † family
Phymatopleuridae
Phymatopleuridae is an extinct family of fossil sea snails, marine gastropod mollusc
Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxo ...
* † family
Polytremariidae
* † family
Portlockiellidae
* † family
Rhaphischismatidae
* † family
Trochotomidae
* † family
Zygitidae
Bouchet and Rocroi (2005) includes the Pleurotomarioidea in the Vetigastropoda, following Ponder and Lindberg (1997), but refers to the Vetigastropoda simply as a clade.
2008 taxonomy
P. J. Wagner 2008
[Classification of P. J. Wagner 2008]
P. J. Wagner. 2008. Paleozoic Gastropod, Rostroconch, Helcionelloid and Tergomyan Database. https://paleodb.org/cgi-bin/bridge.pl?action=displayReference&reference_no=9042 (unpublished). includes the superfamily Pleurotomarioidea, (ex Pleurotomariacea) in the suborder Pleurotomariina and superorder Vetigastropoda. This is an as yet (September 2010) unpublished opinion by Wagner.
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References
{{Taxonbar, from=Q2461972
Vetigastropoda