Taxon profile


Exomilus dyscritus Verco, 1906

kingdom Animalia - animals »  phylum Mollusca - mollusks »  class Gastropoda - gastropods »  order Caenogastropoda »  family Raphitomidae »  genus Exomilus


Length type: 9,1 mm. ; width, 2,7 mm. : aperture, 2,8 mm.; body-whorl, 4,8 mm.


South Australia. Locality of type, St. Vincent Gulf, 22 fathoms with 6 other examples.


Shell solid, long, narrow. Whorls 7. Protoconch 2 whorls, homostrophe, convex, with 20 fine spiral incisions ending abruptly in a varix, white. Spire whorls with angulation at one-fourth the distance from the lower suture; uniformly concave between the angulations; with axial costae, valid, rounded nearly as wide as the interspaces, and spiral line wider anteriorly, wider than their interspaces, crossing the costae, six above the angulation, and two below it; fine accremental stria; under the lens. Suture distinct, linear, undulating, convex between the costae. Body-whorl oblong with two median rounded carinae, the upper larger, more prominent, forming the angulation (in the spire whorls), the lower producing the upper margin of the suture, tuberculated by the axial costae, which cease at the lower one; six spiral lirae above them, two between them, and ten of varying size below them on the concave base. Aperture subtriangular, outer side straight, inner sigmoid. Outer lip thin, slightly excavated just below the suture for one-sixth of its extent to form a shallow sulcus, with a margin feebly thickened and everted, then excavated again to the upper carina, an acute short projection between the two excavations; edge crenulated by spiral line and carinae. Basal lip begins at the lower carina and is concavo-convex to the anterior notch. Columella concavo-convex from behind forwards.
Ornament. The type is white, but a co-type shows a brown tinting of the two carinae and of that part of the axial costae connecting them, most marked at the tubercles of junction. This shell is 10,1 mm. long, and shows fifteen spiral lirae at the base.
[Verco, 1906. Original description]
Author: Jan Delsing

Contributions to BioLib

Help us to expand this encyclopedia! If you are logged in, you can add new subtaxa, vernacular and scientific names, texts, images or intertaxon relationships for this taxon.