Mastonia algens 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 : 61

Mastonia algens Jousseaume, 1898

( Fig. 37 )

Mastonia algens Jousseaume, 1898: 73 , not illustrated.

ORIGINAL LOCALITIES. — Aden, Djibouti.

TYPE MATERIAL. — Syntype. Djibouti • MNHN-IM-2000-732; 1 specimen.

ORIGINAL DESCRIPTION. — Testa solida, obesula , elongato-turrita, apice olivaeforme acuminata, nitens, violacea-alba, sparsim pallide fulva, granulis seriebus duobus distantibus suturam obtegentibus ornata, inter costas funiculus fulvus decurrans; anfr. 16-17 primi 4 nigri, sequentes 4 albi, alteri normales, ultimus seriebus granularum quatuor rugatus, ad basim abrupte attenuatus, in portem costa minore cinctus; apertura sub-rotundata, fissa ovalis profunde secta; canalis recurvus. Long. 8mm; diam. 2mm.

[Latin diagnosis followed by a discussion in French]

TRANSLATION OF THE LATIN TEXT. — Solid shell, swollen, turretedelongated, acute and oval apex, bright, purple-white, scattered in light yellow, adorned by two series of granules distant from each other and hiding the suture, interspaces are characterised by small brown cords; first four spiral cords of whorls 16 and 17 are brown, subsequent four are white, the others are normal, the last whorl is characterised by four granulated spiral cords, abruptly attenuated at the base with a minor spiral cord; roundish aperture, deeply incised with an oval fissure; siphon curved. Length 8 mm; diameter 2 mm.

DIAGNOSIS. — Shell cyrtoconoid. Syntype 5.6 mm high.Teleoconch of 11 whorls. Three spiral cords present, the second appearing on the seventh whorl. First and third cords with tubercles at the intersection with orthocline axial ribs. The second initially as a fine thread, but later developing thin tubercles. Spiral microsculpture of weakly granulate fine threads in the interspaces between the spiral cords. Base with two additional cords of which the first tubercled and the second developing thin tubercles towards the peristome. Protoconch incomplete in the syntype but clearly multispiral. The visible c. 2.5 whorls with two spiral keels and axial riblets. First two teleoconch whorls white, the third and fourth pinkish, remaining teleoconch whorls brownish to light violet with white to light brown tubercles. Darker background between the first and third spiral cords.

Figures

FIG. 37. — Mastonia algens Jousseaume, 1898, Djibouti: A-I, syntype: MNHN-IM-2000-732: front (A, B), side (C, D), back (E), protoconch (F, G), peristome (H), microsculpture (I); J-L, original labels. Scales bar: A-E, 1 mm; F-H, 0.2 mm; I, 0.1 mm.