Ampelita lindae Griffiths & Herbert 2013, sp. n.

Ampelita lindae sp. n.

Fig. 14

Etymology: Named for Linda Davis, manager of the Mollusca collection at the KwaZuluNatal Museum and one of the members of the team that discovered this species.

Diagnosis: Shell discoidal, spire flat or nearly so, periphery rounded; aperture strongly descendant with reflected rim; umbilicus wide; surface rough, sculptured by raised collabral vermiform granules; lustreless, mid-brown with whitish, flake-like markings and a pale peri-umbilical band.

Description:

Shell: Medium sized, relatively thin, discoidal with very low spire (H:D= 0.357 –0.485); periphery at or just above mid-whorl, rounded or weakly angled; a very weak supraperipheral gutter evident in occasional individuals, particularly near start of last whorl; suture indented, final part of last adult whorl descending steeply prior to aperture; umbilicus wide, funnel-shaped. Protoconch of ca 1¼–1½ whorls, the first smooth, thereafter with numerous, irregular, axially elongate granules; junction with teleoconch ill-defined. Teleoconch of a further 2½ whorls; with irregular growth-lines and an uneven sculpture of raised vermiform granules, in a primarily collabral alignment (Fig. 14D); surface thus rendered rough to the touch; granules not simply periostracal, but present on underlying shell; this sculpture continues onto base and into umbilicus. Aperture elongate-ovate, strongly oblique to vertical axis of shell; peristome incomplete, interrupted in parietal region; rim of peristome reflected forming a flaring lip.

Shell lustreless, covered with a predominantly mid-brown periostracum when fresh, with irregular, pale, flake-like markings; underlying shell mostly pale with darker brownish spiral bands either side of a pale, peri-umbilical band; sometimes also darker behind flared aperture lip. Aperture lip white, interior greyish brown in fresh material.

Dimensions: Holotype, max. diameter 30.5 mm, height 12.6 mm; largest specimen, max. diameter 31.4 mm, height 12.7 mm.

Holotype: MADAGASCAR: Central W Madagascar, ca 10 km NE of Belitsaka and ca 60 km E of Maintirano, E side of Tsingy Beanka, in leaf-litter and amongst limestone boulders in tall moist east-facing forest growing on limestone, above Bokarano River Cave, 17.90568°S 44.48822°E, ca 230 m, 29.x.2009, O. Griffiths, D. Herbert, L. Davis & R. Randalana, st’n 07/09 (AMS C.474167).

Paratypes: Same data as holotype (NMSA L8468 /T2903, 1 adult specimen); st’n 07/10 (AMS C.469580, 3 adult specimens); st’n 09/10 (AMS C.469579, 1 adult specimen); st’n 07/10 (TMAM T163, 1 adult specimen).

Distribution: Evidently a narrow-range endemic, currently known only from Tsingy Beanka; not yet known from either Tsingy de Bemaraha or Antsingimavo.

Habitat: Known only from fresh dead shells collected in leaf-litter in tall, east-facing, evergreen forest in the central part of Tsingy Beanka.

Remarks: With its relatively small, very depressed shell and rough, vermiform microsculpture, A. lindae is a distinctive species. A. granulosa (Deshayes, 1840) (from the north-eastern tip of Madagascar), another species with coarse microsculpture, is much larger and has distinct periostracal bristles arising from the granules, a feature not evident in the present species.

Additional material resembling A. lindae has been found as subfossils in the Kasijy Forest (Kelifely Plateau). These are larger (max. diameter 32.9–35.0 mm, height 15.3– 17.9 mm) than the present material but are clearly morphologically close to it. The material available, however, is inadequate to permit thorough study and meaningful comparison.