Obesula senilis Jousseaume, 1898

Albano, Paolo G., Franco, Davide Di, Azzarone, Michele, J., Piet A., Bakker & Sabelli, Bruno, 2023, Review of the types of Indo-Pacific Triphoridae (Mollusca, Gastropoda) in the Muséum national d’Histoire naturelle, Paris, Zoosystema 45 (2), pp. 13-106 : 94

Obesula senilis Jousseaume, 1898

( Fig. 64 )

Obesula senilis Jousseaume, 1898: 75 , not illustrated.

TYPE LOCALITY. — Perim Island, Bab al-Mandab Strait, Yemen.

ADDITIONAL ORIGINAL LOCALITIES. — Djibouti.

TYPE MATERIAL. — Lectotype. • MNHN-IM-2000-29273; here designated.

Paralectotypes. Yemen • MNHN-IM-2000-501; 1 specimen; from type locality • MNHN-IM-2000-1588; 1 specimen; from type locality. • Triphoridae indet., MNHN-IM-2000-29274; 1 specimen; from type locality.

ORIGINAL DESCRIPTION. — Testa solida, ovato-conica, apice acuminata, albo et nigro zonata;

anfr. circiter 12 primi albi, alteri seriebus tuberculorum tribus, mediana saepe minor, series antica alba, alterae castoneo-nigrae, granulae spiraliter et longitudinaliter funiculo junctas, ultimus quique seriebus granularum rugatus, series postice 2 fulvo nigra, pars antica alba, reticulata; apertura pyriformis, lateraliter fissa; canalis brevis recurvus. Long. 3 mm3; diam. 1 mm2.

[Latin diagnosis followed by a discussion in French]

TRANSLATION OF THE LATIN TEXT. — Solid shell, ovate-conical, acute apex, banded in white and brown; about 12 whorls, the first whorls are white, the other whorls with three series of tubercles, often the median series is smaller, the anterior series is white, the others are brownish, granules are spirally and longitudinally jointed to a small spiral cord, last whorl with five granular spiral cords, two posterior cords dark brown, anterior ones are white, reticulated; pyriform aperture, laterally fissured; short and curved siphon. Length 3.3 mm; diameter 1.2 mm.

DIAGNOSIS. — Shell cyrtoconoid. Lectotype 3.1 mm high.Teleoconch of 6 whorls. Three spiral cords present, the second appearing on the fifth whorl. First and third cords with tubercles at the intersection with rather orthocline axial ribs. Second cord initially as a fine thread, but later developing thin tubercles. Spiral microsculpture of fine threads. Posterior sinus shallow. Base with two additional weakly tubercled spiral cords, the second smaller. Protoconch damaged in the lectotype. First two teleoconch whorls white, other teleoconch whorls brown with the third spiral cord white. Tip of the siphonal canal and protoconch white.

REMARKS. — The type series contained a very worn specimen ( Fig. 63 I-M) which likely belongs to a different species due to the more ovoid shape, the colour pattern on the last whorl (with the first spiral cord white rather than pearly on brown background), the tubercles on this last whorl more elongated, and the lack of an intermediate second spiral cord. Therefore, se designated a lectotype of O. senilis to stabilize the nomenclature.

Figures

FIG. 64. — A-H, Obesula senilis Jousseaume, 1898, Perim Island, Bab al-Mandab Strait, Yemen, lectotype, MNHN-IM-2000-29273: front (A, B), side (C, D), back (E), apex (F, G), microsculpture (H); I-M, Triphoridae indet. (non O. senilis), Perim Island, Bab al-Mandab Strait, Yemen, paralectotype, MNHN-IM-2000-29274: front (I, J), side (K), back (L), microsculpture (M); N, O, original labels lot 2000-29273. Scale bars: A-E, 1 mm; F, G, 0.1 mm; H, M, 0.2 mm; I-L, 0.5 mm.

FIG. 63. — Inella rossiteri Jousseaume, 1884, New Caledonia: A, original figure in Jousseaume (1884); B-K, lectotype, MNHN-IM-2000-29272: front (B, C), side (D, E), back (F), peristome (G, H), protoconch (I, J), microsculpture (K); L, M, original labels lot MNHN-IM-2000-29272; N-Q, Paralectotype,MNHN-IM-2000-1246; front (N), side (O), back (P), protoconch (Q); R, Triphoridae indet., paralectotype, MNHN-IM-2000-1313; front; S-T, original labels lot MNHN-IM-2000-1313. Scale bars: A-F, N-P, R, 1 mm; G, H, 0.4 mm; I, J, 0.1 mm; K, 0.2 mm; Q, 0.5 mm.