Taxon profile
species
Opisthostoma dihelicton J.J. Vermeulen, 1994
kingdom Animalia - animals » phylum Mollusca - mollusks » class Gastropoda - gastropods » order Architaenioglossa » family Diplommatinidae » genus Opisthostoma
ID: 1652570
pID: 653058
Taxonomic rank: 150
Author of the record: Delsing Jan
Created: 2021-06-06 19:30:03 - User Delsing Jan
Data last updated: 2021-06-06 19:30:42
URL: https://www.biolib.cz/en/taxon/id1652570/
Text function: [[t:1652570;<em>Opisthostoma dihelicton</em>]]
[[t:1652570;<em>Opisthostoma dihelicton</em>]] J.J. Vermeulen, 1994
Reference: <a href="https://www.biolib.cz/en/taxon/id1652570/"><em>Opisthostoma dihelicton</em></a>
pID: 653058
Taxonomic rank: 150
Author of the record: Delsing Jan
Created: 2021-06-06 19:30:03 - User Delsing Jan
Data last updated: 2021-06-06 19:30:42
URL: https://www.biolib.cz/en/taxon/id1652570/
Text function: [[t:1652570;<em>Opisthostoma dihelicton</em>]]
[[t:1652570;<em>Opisthostoma dihelicton</em>]] J.J. Vermeulen, 1994
Reference: <a href="https://www.biolib.cz/en/taxon/id1652570/"><em>Opisthostoma dihelicton</em></a>
Data source: World Wide Mollusc Species Data Base.
Images
Author: Vermeulen, J.J.
Description
Author: Jan Delsing
Text ID: 109568
Text Type: 1
Page: 0
Created: 2021-06-06 19:32:40 - User Delsing Jan
Language: EN
Text function: [[t:1652570,textblock=109568,elang=EN;Description]]
Text ID: 109568
Text Type: 1
Page: 0
Created: 2021-06-06 19:32:40 - User Delsing Jan
Language: EN
Text function: [[t:1652570,textblock=109568,elang=EN;Description]]
Material seen. — SARAWAK. 1st Div.: SE. end of limestone outcrop S. of Bau (leg. Wilford, UF 194692/10, inch HOLOTYPE; do. 194693/10).
Spire cylindrical. Apex distinctly oblique. Whorls 3 1/2-3 5/8, convex; last whorl rounded. Constriction with a transverse palatalis, sometimes with an inconspicuous columellaris. Tuba entirely distant from the spire, gradually narrowed towards the constriction, rounded below. Radial ribs very closely placed (20-26 ribs/0.5 mm on the penultimate whorl, 16-22 ribs/0.5 mm half-way the tuba), not sinuous. Spiral striation present, inconspicuous. Umbilicus open, 0.1 mm across. Aperture tilted up to 15° with regard to the coiling axis, its upper margin slightly above to widely below the level of the apex, circular to slightly elliptic. Peristome distant from the spire, simple, somewhat spreading. Spire: height and width 0.8-0.9 mm; index 1.0-1.1. Total width 1.4-1.6 mm. Height aperture 0.35-0.45 mm; width 0.35-0.40 mm.
Distribution. — Borneo: Sarawak, 1st Div., limestone range SE. of Bau.
Notes. — 1.0. asyndeton as well as 0. telestoma have much wider spaced ribs.
2. The name refers to the fact that the densely ribbed shell somewhat resembles a twice-coiled spring.
Spire cylindrical. Apex distinctly oblique. Whorls 3 1/2-3 5/8, convex; last whorl rounded. Constriction with a transverse palatalis, sometimes with an inconspicuous columellaris. Tuba entirely distant from the spire, gradually narrowed towards the constriction, rounded below. Radial ribs very closely placed (20-26 ribs/0.5 mm on the penultimate whorl, 16-22 ribs/0.5 mm half-way the tuba), not sinuous. Spiral striation present, inconspicuous. Umbilicus open, 0.1 mm across. Aperture tilted up to 15° with regard to the coiling axis, its upper margin slightly above to widely below the level of the apex, circular to slightly elliptic. Peristome distant from the spire, simple, somewhat spreading. Spire: height and width 0.8-0.9 mm; index 1.0-1.1. Total width 1.4-1.6 mm. Height aperture 0.35-0.45 mm; width 0.35-0.40 mm.
Distribution. — Borneo: Sarawak, 1st Div., limestone range SE. of Bau.
Notes. — 1.0. asyndeton as well as 0. telestoma have much wider spaced ribs.
2. The name refers to the fact that the densely ribbed shell somewhat resembles a twice-coiled spring.
Vermeulen, J.J., 1994. Notes on the non-marine molluscs of the island of Borneo 6. The genus Opisthostoma (Gastropoda Prosobranchia: Diplommatinidae), part 2
Author: Jan Delsing