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Taxon profile

species

Philine araneosa van der Linden, 1995

kingdom Animalia - animals »  phylum Mollusca - mollusks »  class Gastropoda - gastropods »  order Opistobranchia - opisthobranchs »  family Philinidae »  genus Philine

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Philine araneosa

Author: Linden, Van der

Description

Description (after 31 shells from 12 localities). - The shell is minute (length 0.8-1.8 mm) and has an oval shape, somewhat cylindrical by the straight and almost vertical outer lip (shell in ventral view, top on the upper side). In side view the margin of the outer lip is sinuous due to a depression in the middle. The last half whorl, the aperture, is rather convex, bowl-shaped, especially because the margin of the outer lip (seen from the top of the shell) is projected above the level of the spire. The upper edge of the aperture is in line with the top of the spire, or a little below it. The basis and the inner side of the aperture are gently rounded (the last one not sinuous). The spire has about 1.5 whorls, near the top somewhat swollen. The lop of the spire is remarkably flat and the suture is very indistinct. At 30x magnification the microsculpturc consists of many uninterrupted, incised spiral lines, more or less irregular like spun threads and standing away from each other. They are crossed by numerous close-set and sinuous growth-lines, often more prominent near the edge of the aperture. Colour: transparent and glossy; old, empty shells are opaque while, often with a transparent /one in the middle.
Source: Van der Linden, 1995. Philinidae, dredged by the CANCAP expeditions. (Original description)

Interchangeable taxa

Most certainly P. punctata J. Adams, 1800, which has not been found in the area investigated, is the closest related species: the shells have the same length, the same convexity of the spire and aperture and about the same profile. Nevertheless, the microsculpture is different: araneosa has uninterrupted spiral lines and punctata has spirally arranged rows of separate dots or rings (Van der Linden, 1994). There are only few species with the same spiral sculpture as shown by P. araneosa. P. amabilis Verrill, 1880 (pp. 398-399) from the West Atlantic is a large (length 15 mm) species; the shell was not figured by Verrill (1880) or Pilsbry (1895-1896), but a drawing was given by Abbott (1974, no. 3967). It is quite clear that amabilis is completely different, with a less conspicuous and more loosely coiled spire and with the upper edge of the aperture somewhat projecting above the top of the spire. P. azorica Bouchet, 1975 has about the same characters but difierent from araneosa (and P. amabilis). P. azorica has a callus, bordering on the sinuous spire, and a more ample aperture. P. infundibulum Dall, 1889 is a large (length 12 mm) species too; like P. amabilis, it has a loosely coiled and inconspicuous spire. This species is figured by Rios (1975, no. 693); it seems to be very closely related lo P. amabilis. Finally. P. finmarchica M. Sars, 1870, P. pruinosa (Clark, 1827) and P. monterosatoi Dautzenberg,1891 (non P. monterosati Vayssiére, 1885) have very close-set and (especially the first two species) much coarser and raised spiral lines.
Source: Van der Linden, 1995. Philinidae, dredged by the CANCAP expeditions.

Distribution

Cape Verde Islands, W. of Boa Vista
Author: Jan Delsing

Links and literature

EN Galli C.: WMSDB - Wolrdwide Mollusc Species Data Base July 10, 2013 [http://www.bagniliggia.it/WMSD/WMSDhome....] [as Philine araneosa Van Der Linden, 1995]
Data retrieved on: 23 November 2013

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