OLIVERIO

(FIGS 2, 3, 5A, 7C, 9E, 10G, 11G)

Zoobank registration: urn: lsid: zoobank. org:act: 210F01F5-C95D-4F27-A63D-9715015E67EE

Type material: Holotype: MNHN-IM-2009-16140 (Sud Madagascar, Lavanono West sector, ATIMO VATAE/ BP21, 25°23.1–23.2ʹS, 44°51.4–51.6ʹE, 20 m deep, female).

Material examined: MNHN-IM-2009-16140 (Sud Madagascar, Lavanono West sector, ATIMO VATAE/ BP21, 25°23.1–23.2ʹS, 44°51.4–51.6ʹE, 20 m deep, female).

Description: Body of medium size for the genus, 1 cm total length. Shell very thin, weakly calcified; ear shaped, low spire, with expanded aperture; weakly sculptured by axial growth lines; completely enclosed by the mantle. Periostracum not visible.

Protoconch of 1.6 whorls; nucleus diameter 110 μm; protoconch I 1.2 whorls, smooth, with subsutural axial folds; protoconch II with axial growth lines; protoconch–teleoconch boundary distinct.

Mantle dome shaped, outline rounded; thin; with anterior siphon folds; texture slightly wrinkled; dorsal mantle colour light violet, patterned with several small white and beige spots, fewer bigger orange spots and some brown patches.

Penis unknown; vas deferens unknown.

Radula reduced taenioglossate, formula 0:1:1:1:0; rachidian tooth base bifurcated; rachidian cusp with three external long denticles on each side; lateral teeth elongated, with a pointed triangular external cusp, with four or five long denticles on each side.

Jaws short; with an external protrusion on the upper side.

Distribution: So far known only from the type locality (southern Madagascar), 20 m deep.

Etymology: From the Latin adjective lentiginosa, meaning ‘freckled’, referring to the dorsal coloration of the holotype.

Remarks: This species is known only from shallow waters of southern Madagascar. Owing to the high variability in shell shape and mantle coloration in this family, the most reliable way to identify this species remains by molecular analysis.