Ampelita namerokoensis : Fischer-Piette 1952
Creators: name: Griffiths, O. L.
name: Herbert, D. G.
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Stylommatophora
Acavidae
Ampelita
Ampelita namerokoensis

description: Ampelita namerokoensis Fischer-Piette, 1952
Figs 17E, 17F, 19, 20, 25F
Ampelita namerokoensis: Fischer-Piette 1952: 35, pl. 3, figs 35–39; Fischer-Piette et al. 1994: 123, pl. 15, figs 5–8. Type loc.: ‘ Gorges de Salapango [= Salapanga], Bemaraha’, Madagascar.
Morphological notes:
External features (Fig. 25F): Head-foot mostly dark grey-brown with uniformly granular skin texture; optic tentacles slightly paler, running into similarly pale bands along neck; skin granules with microscopic ochre-brown pigment granules; lining of mantle cavity with some black pigmentation (not dense) and a pattern of pale circular blotches.
Distal genitalia (Fig. 20): Resembling those of A. beanka, but differing considerably in penis morphology, particularly its internal structure. Penis shorter (ca 3.2 mm) and more slender than in A. beanka, and the apical region less swollen; vas deferens follows a similar path alongside penis, running to its apex and then recurving before inserting subterminally via a short, somewhat broader, pale flesh-coloured epiphallus; details of recurved vas deferens and epiphallus mostly concealed by attachment of retractor muscle. Interior of penis with a small conical papilla at insertion of epiphallus, from which a single mid-line fold runs to penis base; additional concentric folds surround papilla on both sides, these converging and evanescing toward penis base; the resultant pattern of folds differing considerably from that of A. beanka.
Locality data: Tsingy Beanka: st’ns 03/06, 11/06, 12/06, 14/06, 16/06, 18/06, 02/09, 06/09, 07/09, 08/09, 09/09, 11/09, 01/10, 02/10, 05/10, 07/10, 08/10, 09/10, 10/10. Bemaraha: st’ns 14/95, 09/96, 12/96.
Distribution: Restricted to central western Madagascar, with reliable records only from the Tsingy de Bemaraha and Tsingy Beanka; not found at Antsingimavo and, despite its name, evidently does not occur in Nameroko [Namoroka] (see Remarks below).
Habitat: Living specimens are found most commonly amongst limestone rocks and in leaf-litter. In Tsingy Beanka, it occurs mostly in the southern region, in taller, moister forests.
Remarks: Shell lenticular, of moderate size (max. diameter <26 mm, but rarely more than 23 mm), carinate at periphery; uniformly light brown when fresh, with a pale yellowish band around the umbilicus. Protoconch essentially smooth (Fig. 17E), but sometimes with microscopic traces of oblique, close-set striae on last embryonic whorl, forming an extremely fine criss-cross pattern. Teleoconch with fine spiral sculpture (Fig. 17F). The choice of name for this species is puzzling since the type locality [Salapanga] is in the Tsingy de Bemaraha. Fischer-Piette (1952) mentioned material from Ambongo (collected by G. Petit and H. Perrier de la Bâthie), which he equated with the ‘Tsingy de Nameroko’. Elsewhere, however, Fischer-Piette and Bedoucha (1965: 62) stated that Salapanga [known to be in the Bemaraha] was also in the Ambongo region, suggesting in this case that Ambongo equates with Bemaraha. In line with this, S. Goodman (pers. comm. 2010), confirmed that Ambongo has been used for both Bemaraha and Namoroka. There is therefore some doubt regarding the occurrence of this species in Namoroka and despite survey work (Griffiths in 1997 and Emberton in 2007), no specimens have been found there.
Additional material from the Kelifely Plateau (st’ns 06/05, 10/05) resembles this species in having spiral sculpture, but the protoconch is sculptured with distinct axial riblets like that of A. milloti.At this stage its identity remains puzzling. Further subfossil or very old dead specimens from limestone caves in the Anjajavy– Narinda area, northeast of Mahajanga (Griffiths pers. observ.) may also be referable here.
description: Published as part of Griffiths, O. L. & Herbert, D. G., 2013, New species of land snails (Mollusca: Gastropoda) from two isolated karst formations in central western Madagascar: Tsingy Beanka and Antsingimavo, with additional notes on other regional endemics, pp. 1-48 in African Invertebrates 54 (1) on pages 27-29, DOI: 10.5733/afin.054.0101, http://zenodo.org/record/7670100