Mastonia interpictus 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 : 73-75

Mastonia interpictus Jousseaume, 1898 ( Fig. 49 )

Mastonia interpictus Jousseaume, 1898: 74 , not illustrated.

ORIGINAL LOCALITIES. — Djibouti, La Réunion.

TYPE MATERIAL. — Syntype. Reunionisland • MNHN-IM-2000-1575; 1 specimen; La Réunion .

ADDITIONAL MATERIAL. — Reunion island • MNHN-IM-2012-36199; 1 specimen; Mastonia sp. ( M. interpictus sensu Jay, 2007 ) .

ORIGINAL DESCRIPTION. — Testa solida, ovato-turrita, apice alba acuminata, cinereo-alba, fulvo picta; anfr. 14 plani sutura lata separati, transversim duplice serie granularium cincti, granulae alternantes aequales albae, intervalles castaneo-fusco punctati, ultimus seriebus granularum quinque majores 3 interpicturati, alteri 2 minores unicolores rugatus; apertura rotundata, peristomum postice profunde fissa, canalis brevis retrorsum curvatus. Long. 5mm; diam. 1mm 5.

[Latin diagnosis followed by a discussion in French]

TRANSLATION OF THE LATIN TEXT. — Solid shell, turreted-ovate with a sharp white apex and coloured in greyish-white and yellow; 14 flattened whorls separated by a large suture, with two series of granules, which are white, alternating and equal, interspaces are adorned by dark brown spots, of the last series of five granules the three wider series are coloured in the interspaces, the two other smaller series are monochrome; rounded aperture, peristome posteriorly deeply fissured, the siphon is short and curved backwards. Length 5 mm; diameter 1.5 mm.

DIAGNOSIS. — Shell slightly cyrtoconoid. Syntype 4.9 mm high. Teleoconch of c. 9 whorls. Two spiral cords present. A spiral thread present below the first spiral cord on the last whorl. A fine thread present suprasuturally. Both spiral cords with tubercles at the intersection with prosocline axial ribs. Spiral microsculpture of numerous fine threads. Base with two additional spiral cords of which the first with tubercles, the second smooth. First two teleoconch whorls white, other whorls brown with darker interspaces between the tubercles. Protoconch missing in the syntype.

REMARKS. — The M. interpictus illustrated by Jay (2007) in figures 34-36 and 57 does not fit the type specimen: it is broader and more pyriform, it has a more developed, albeit small, second spiral cord, and it has multiple minute spiral cords which form a cancellate sculpture at the intersection with growth lines. The colouration is also different: M. interpictus is whitish with brown interspaces between nodules. Jay’s figure 57 shows a shell with whitish background but irregular brown blotches on the whorls that cover also the tubercles.

Figures

FIG. 49. — Mastonia interpictus Jousseaume, 1898, La Réunion; MNHN-IM-2000-1575: front (A, B), side (C, D), back (E), microsculpture (F); G, H, original labels, Scale bars: A-E, 1 mm; F, 0.2 mm.