Monilearia (Lyrula) multipunctata ( Mousson, 1872 )

Ibáñez, Miguel, Groh, Klaus, Alonso, María R. & Castillo, Carolina, 2006, The subgenus Monilearia (Lyrula) Wollaston, 1878 (Gastropoda: Helicoidea: Cochlicellidae) from Lanzarote and Fuerteventura (Canary Islands), with the description of Monilearia (Lyrula) tubaeformis sp. nov., Zootaxa 1320, pp. 29-41 : 35-37

Monilearia (Lyrula) multipunctata ( Mousson, 1872)

Helix [ Discula ] multipunctata Mousson, 1872 , 54–55, 153, 162, pl. 3 fig. 16–18. Type locality: "Fuerteventura". It was considered as extinct by the author.

Material. Holotype (empty shell): Helix multipunctata (ZMZ 505020, leg. Fritsch, 1863, subfossil). 43 total specimens and 136 empty shells collected between March 1989 and May 2005, in several localities of Fuerteventura ( Fig. 1 ).

Distribution and habitat ( Fig. 1 ). A species endemic to Fuerteventura, where it occurs in dry areas with lowland vegetation, at an altitude of 10– 300 m.

Description. The soft body is coloured light brown, the dorsal part being darker.

The shell ( Fig. 3 E,F) is discoid, with the spire little elevated or even nearly flat but with the protoconch projecting; with 3½–4 moderately convex whorls, distinctly angulated at the periphery; suture deep; umbilicus slightly eccentric, moderate wide, deep and open. The last quarter of the body­whorl is bent downwards obliquely. Aperture well rounded, square ovate, sometimes weakly angulated at the palatal side, the peristome margins normally united and slightly detached from the last whorl; the peristome has a very narrow (0.1–0.2 mm) reflected white lip. In the exceptional cases where the lip is discontinuous, its insertion points at the last whorl are mutually separated less than 0.7 mm.

The ornamentation is stronger on the dorsal side, similar to that of M. loweana ( Fig. 3 F). The protoconch is brown, with 1–1¼ whorls, initially smooth (approximately ¼–½ whorls) while its distal part bears very fine radial ribs. The teleoconch is also brown alternating with irregular whitish radial streamers, more frequent in the last 1½ whorls of the dorsal side; in the ventral side the streamers are less conspicuous. There are two darker brown spiral bands above and below the periphery, irregularly interrupted by light brown dashes.

Usually it has a dark mantle with whitish stains (in some specimens the whitish surface area is larger than the dark one). The kidney measures less than half the length of the lung; the secondary ureter is extremely short, almost missing. In fully mature specimens, the genital system (Fig. 5B) occupies nearly the whole visceral bulk, the spermoviduct being the most voluminous part. Several specimens of the population located immediately north of “El Jable” ( Fig. 1 ) had a duplicated male duct (Fig. 5C).

Figures

FIGURE 1. Geographical distribution of Monilearia tubaeformis sp. nov., M. multipunctata, and M. loweana. Symbols represent 1 x 1 km UTM squares.

FIGURE 3. Shell and SEM details. A – D. Monilearia loweana; A. from Valle Chico; B – D. from Mirador de Malpaso; C. Some bristles of third whorl rectangular “ cells ”; D. “ cell ” subdivisions and a line of bristles between second and third whorls; E – F, Monilearia multipunctata; E. from Barranco de Gran Valle; F. from Rosa de Zapata; G – H, Monilearia tubaeformis sp. nov. G. Holotype, from Lomo del Aceituno; H. Paratype, from Vega de Río Palmas, detail of shell ventrallateral side. Scale bar (2 mm) applies to A, E, F, G.