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species

Joculator melanoraphis Jay & Drivas, 2002

kingdom Animalia - animals »  phylum Mollusca - mollusks »  class Gastropoda - gastropods »  family Cerithiopsidae »  genus Joculator

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Joculator melanoraphis

Author: Jay & Drivas

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Description

Shell pupiform, rather globose, with strongly constricted base and high protoconch. Protoconch of 3.5 smooth convex and translucent whorls, rounded apex, well delimited from teleoconch by an oblique line marking change of sculpture. Teleoconch of 7 whorls with straight sides and shallow suture. 3 spiral cords per whorl, the uppermost one a little weaker on first whorl, but equal to the other ones on following whorls. Rounded and widely-spaced axial ribs, a little smaller than cords, crossing them at right angles, with a rounded bead at each intersection, beads close-set and numbering 16 or 17 per whorl. On fresh specimens, very tine axial riblets visible under microscope on whole surface including cords and ribs, numbering 6 to 7 in each interval. A fourth spiral cord emerging from suture at base of last whorl, with only weak swellings rather than beads; a fifth smooth cord on base of mature specimens. Aperture circular. Colour plain beige to pale brown; suture, base and protoconch darker brown. On fresh specimens, the upper cord is a little darker than the other ones, but remains clearly paler than suture. Size: holotype total height 2.9 mm, maximum width 1 mm; height of protoconch 0.44 mm; width of protoconch at base 0.30 mm.
Source: Jay, M. & Drivas, J, 2002. The Cerithiopsidae (Gastropoda) of Reunion Island (Indian Ocean)

Interchangeable taxa

Dizoniopsis herosae which has the same colour and a brown suture, is easily separated from this species by its 2 spiral cords instead of 3, and its axially ribbed protoconch. The other species discussed below lack the darker suture: Joculator granata Kay, 1979, is higher and less constricted basally, and its upper cord is weaker on all whorls; it also has a crimped suture on the protoconch whorls. Joculator keratochroma is of the same shape, but is smaller and has a plain coloration; Joculator lozoueti can be separated on account of its more ventricose shape, its white protoconch and the plain, darker colour of the teleoconch; Bittium (Joculator) tenthrenois Melvill, 1896 from Bombay, differs in its more ventricose shape and its plain brown colour; Cerithiopsis (Joculator) ridicula Watson, 1866 from Wednesday Isl., NE Australia, differs in having only 3 teleoconch whorls, and its upper cord is weaker on all whorls, and its coloration plain; Joculator minima Laseron, 1955, J. niasensis (Thiele, 1925), and J. psyllos are of similar shape, but are much smaller.

Distribution

Réunion: Found dead in hand-dredged sand at 10-30 m, off Saint-Gilles-les-Bains, between harbour and Boucan-Canot beach.
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 Joculator melanoraphis Jay & Drivas, 2002]
Data retrieved on: 2 May 2017

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