Pleurotomella Explained

Pleurotomella is a genus of sea snails, marine gastropod mollusks in the family Raphitomidae.

Description

(Original description by Verrill) As at present understood, this genus is intended to include those species which have a rather broad and very distinct subsutural band, crossed by excurved lines of growth corresponding to the form of the posterior sinus of the lip, which is situated a little below the suture and is always pretty well-developed, but is sometimes broad and shallow, and at other times narrower and very deep. The outer lip is always thin and sharp, without any appearance of a varix, nor is there any deposit of callus on the body whorl, in front of the aperture. The siphonal canal is well developed, generally constricted at the base and somewhat elongated, and usually but slightly curved. In a few of the species, doubtfully referred to hie genus, it is short and wide. The columella-margin is more or less sinuous. The protoconch differs in sculpture, and usually in color, from the rest of the whorls, and is generally minutely cancellated by fine raised lines running obliquely in opposite directions. The remaining whorls are elegantly sculptured by longitudinal ribs and revolving cinguli, and usually have a distinct shoulder or carina, which is frequently nodulous, below the subsutural band. The animal is destitute of an operculum, and, in all the species hitherto examined, is without eyes. The dentition consists of rather strong uncini, usually with a barbed tip and broad base.[1]

(Description by Dall) The larval shell is multispiral. The adult shell shows a small blunt protoconch of several (usually) swollen whorls, closely arcuately axially ribbed. This protoconch is dark and sculptured with criss-cross lines, strongly contrasting with the rest of the shell. The succeeding short-fusiform whorls have an axial and (fainter) spiral sculpture. The anal sulcus is close to the suture, deep and wide, with a distinct fasciole. The siphonal canal is very short, narrow, recurved. The outer lip is thin, simple and sharp. The columella is thin, gyrate, anteriorly obliquely truncate, almost pervious. The animal is blind and lacks an operculum[2]

Species

Species within the genus Pleurotomella include:

Synonyms

References

External links

Notes and References

  1. https://biodiversitylibrary.org/page/7477234 Verrill A. E. (1884). Second catalogue of mollusca recently added to the fauna of the New England Coast and the adjacent parts of the Atlantic, consisting mostly of deep sea species, with notes on others previously recorded. Transactions of the Connecticut Academy of Arts and Sciences, 6(1): 139-294, pl. 28-32
  2. https://archive.org/details/mobot31753003646038 W.H. Dall (1908) Reports on the Mollusca and Brachiopoda, Bulletin of the Museum of Comparative Zoology at Harvard College. vol. 43

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