Orinella alfredensis

Orinella alfredensis is a species of sea snail, a marine gastropod mollusk in the family Pyramidellidae, the pyrams and their allies.[1]

Orinella alfredensis
Drawing of a shell of Orinella alfredensis
Scientific classification
Kingdom:
Animalia
Phylum:
Mollusca
Class:
Gastropoda
(unranked):
clade Heterobranchia
clade Euthyneura
clade Panpulmonata
Superfamily:
Pyramidelloidea
Family:
Pyramidellidae
Genus:
Orinella
Species:
O. alfredensis
Binomial name
Orinella alfredensis
(Bartsch, 1915)
Synonyms[1]
  • Pyramidella alfredensis Bartsch, 1915
  • Pyramidella (Orinella) alfredensis Bartsch, 1915

Description

The milk-white shell has an elongate-conic shape. The 1¾ whorls of the protoconch are very small. They are planorboid, having their axis at right angles to that of succeeding turns. The left side of the nucleus projects considerably beyond the outline of the spire of the teleoconch . The ten whorls of the teleoconch are almost flat and are feebly shouldered at the summit. They are marked by exceedingly fine, retractive, incremental lines, and numerous microscopic spiral striations. The suture is moderately constricted. The periphery of the body whorl is well rounded. The base of the shell is well rounded, decidedly umbilicated, and marked like the spire. The aperture is subquadrate. The posterior angle is acute. The outer lip is thin. The inner lip is very oblique, and decidedly reflected. It is provided with a strong fold near its insertion. The parietal wall is glazed with a thin callus.[2]

Distribution

This marine species occurs off Port Alfred, South Africa.

References
  1. Rosenberg, G. (2011). Orinella alfredensis (Bartsch, 1915). Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=588521 on 2012-01-12
  2. P. Bartsch (1915), Report on the Turton Collection of South African Marine Mollusks, with Additional Notes on Other South African Shells Contained in the United States National Museum; Bulletin of the United States National Museum, (91): i-xii, 1-305, 54 pls
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