Cyclopedus anselini, Gargominy & Muratov, 2012

Gargominy, Olivier & Muratov, Igor V., 2012, New taxa of land snails from French Guiana, Zoosystema 34 (4), pp. 783-792 : 785-786

Cyclopedus anselini n. sp.

( Fig. 2 )

TYPE MATERIAL. — Holotype: French Guiana, Réserve naturelle des Nouragues, Nouragues field station (c. 4°05’N, 52°41’W; N10 square), 140 m a.s.l., T. E. J. Ripken & O. Gargominy, 11.XI.1997, leaf litter on lateritic soil in a natural forest gap ( INVMAR21029 ), MNHN 25066 . Paratypes: same data as holotype, 1 specimen used for SEM photographs, MNHN 25067 . — Same data, but M12 square, 08.XI.1997, leaf litter on lateritic soil ( INVMAR21021 ), 1 specimen, MNHN 25138 . — Same data, but N15 square, 155 m a.s.l., 15.XI.1997, leaf litter in buttresses of tree (tree code N-15-138) ( INVMAR21038 ), 1 specimen, MNHN 25139 .

OTHER MATERIAL EXAMINED. — Same data as paratype MNHN 25139, 3 damaged shells ( MNHN).

TYPE LOCALITY. — Nouragues field station (c. 4°05’N, 52°41’W), Réserve naturelle des Nouragues, French Guiana.

ETYMOLOGY. — This species is dedicated to Anselin Baradat for the most powerful bond that ties him with the first author.

DIAGNOSIS. — A small South American cyclophoroid species (less than 3.5 mm in height and less than 4.2 mm in diameter) characterised by its unique teleoconch sculpture of fine impressed dots arranged in spiral lines. Operculum almost circular, without any visible steps on both sides, with elevated translucent lamellae expanded at the summit and connected to the succeeding whorl, thus forming a completely closed channel in cross section.

DESCRIPTION (HOLOTYPE)

Shell small (height 3.2 mm, major diameter 3.7 mm), umbilicate,dextral,broadly conical with straight outline, elevated, rather thin, light corneous, semi-translucent. Whorls 3.9, regularly rounded with a deep straight suture all the way to the aperture. Protoconch two whorls,with eight spiral flat ribs.Protoconch/teleoconch transition distinct because of change in microsculpture and discontinuity of growth.Surface of teleoconch with growth lines and four varices (discontinuity in growth) in the first 3+ whorls; sculpture of fine impressed dots arranged in spiral lines irregularly spaced from 0.1 to 0.75 mm and inconspicuous ribs (about 40 on the body whorl) separated by 5-10 growth lines.Aperture circular, not cut by penultimate whorl and almost detached from it. Peristome almost complete, simple, acute,not reflected.Umbilicus open, 5.5times smaller than major diameter, V-shaped.

Operculum almost circular (1.8× 1.7 mm), corneous, externally concave and internally convex,spirally coiled having the elevated translucent lamellae expanded at the summit and connected to the succeeding whorl, thus forming completely closed channel in cross section.

HABITAT. — Primary forest,under leaf litter on lateritic soil.

REMARKS

The holotype is somewhat juvenile but was chosen as the operculum was available. In fully grown specimens, the aperture is clearly delineated from the penultimate whorl although not detached.

By comparison with species listed by Torre et al. (1942), Cyclopedus anselini n. gen., n. sp. seems to be the smallest known cyclophoroid in the western hemisphere.

Clade STYLOMMATOPHORA Schmidt, 1855 Super-family TESTACELLOIDEA Gray, 1840 Family SPIRAXIDAE Baker, 1939 Subfamily SPIRAXINAE Baker, 1939

Figures

FIG. 2. — Cyclopedus anselini n. gen., n. sp.: A, B, holotype MNHN 25066 (B: operculum); C, D, paratype MNHN 25067, details of protoconch (C) and teleoconch sculptures (D). Scale bars: A, 2 mm; B, 1 mm; C, D, 200 µm.