Ampelita namerokoensis Fischer-Piette, 1952

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, African Invertebrates 54 (1), pp. 1-48 : 27-29

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 .

Figures

Fig. 17. Ampelita beanka sp. n., A. milloti Fischer-Piette, 1952 and A. namerokoensis Fischer-Piette, 1952, protoconch morphology and teleoconch microsculpture: (A, B) A. beanka, protoconch diameter 4.1mm, st’n R04/09, respectively paratype, NMSA L8504/T2983, and holotype, AMS C.474166; (C, D) A. milloti, protoconch diameter 4.4 mm, both st’n 07/09, NMSA L8502; (E, F) A. namerokoensis, protoconch diameter 3.5 mm, respectively st’n 18/06, NMSA L8439, and st’n 03/06, NMSA L7038.

Fig.19. Ampelita namerokoensis Fischer-Piette, 1952:(A–C) typical specimen, Tsingy Beanka, st’n 07/09, max. diameter 22.1 mm, NMSA L8445; (D) depressed specimen, Tsingy Beanka, st’n 12/06, max. diameter 23.1 mm, NMSA L8440.

Fig.20. Ampelita namerokoensis Fischer-Piette,1952,genitalia,NMSA L8442:(A)entire reproductive tract; (B) external view ofpenial complex;(C) penis opened longitudinally to showinternal folds andraised papilla at insertion of epiphallus. Abbreviations: ag – albumen gland, bc – bursa copulatrix, bcd – bursa copulatrix duct, ep – epiphallus, ga – genital atrium, hd – hermaphrodite duct, od – oviduct, p – penis, pf – folds lining penis lumen, pp – penis papilla, pr – prostate, prm – penial retractor muscle, v – vagina, vd – vas deferens.

Fig. 25. Living animals from Tsingy Beanka: (A) Acroptychia bathiei Fischer-Piette & Bedoucha, 1965, st’n 13/06, shell diameter 23.2 mm, NMSA L7315; (B) Tropidophora humbug sp. n., st’n 12/06, shell diameter 28.3 mm, paratype,NMSA L7204/T2984; (C) Tropidophora secunda Fischer-Piette & Bedoucha, 1965, st’n 03/06, shell diameter approx.19.0 mm; (D) Clavator griffithsjonesi Emberton, 1999, st’n 12/06, shell height 94.8 mm, NMSA L7192; (E) Ampelita milloti Fischer-Piette,1952,st’n 07/09, shell diameter 19.2 mm, NMSA L8502; (F) Ampelita namerokoensis Fischer-Piette, 1952, st’n 12/06, shell diameter 20.3 mm, NMSA L8442; (G) Kalidos griffithshauchleri Emberton, 2002, st’n 12/06, shell diameter approx. 60 mm; (H) Kalidos maryannae sp. n., st’n 12/06, shell diameter 22.5 mm, paratype, NMSA L7193/T2944.