Ampelita milloti 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 : 26-27

Ampelita milloti Fischer-Piette, 1952

Figs 17C, 17D , 18 , 25E

Ampelita milloti: Fischer-Piette 1952: 34 , pl. 3, figs 31–34; Fischer-Piette et al. 1994: 123, pl. 15, figs 1–4. Type loc.: ‘ Gorge de Salapango [= Salapanga], Bemaraha’, Madagascar.

Morphological notes:

External features ( Fig. 25E ): Head-foot uniformly dark, charcoal-grey to black; skin texture uniformly granular throughout; lining of mantle cavity heavily pigmented with black and patterned with pale circular blotches (observations based on a single livecollected individual).

Distal genitalia: The single preserved specimen available (shell diameter 19.2 mm) possessed an immature reproductive tract. The distal genitalia were thus poorly developed and inadequate for comparative study. From what could be seen of the penis, it appeared similar to that of A. namerokoensis .

Locality data: Antsingimavo: st’ns 4/06, 8/06 (all subfossil). Tsingy Beanka : st’ns 12/06, 14/06, 16/06, 18/06, 02/09, 06/09, 07/09, 08/09, 01/10, 06/10, 07/10, 08/10, 09/10. Tsingy de Bemaraha: st’ns 07/95, 10/95, 14/95, 18/95, 19/95, 9/96, 10/96, 12/96. South bank of Tsiribihina River: st’ns 01/99LP, 02/99LP.

Distribution: Evidently a narrowly endemic species, currently known only from the south bank of Tsiribihina River, Tsingy de Bemaraha and Tsingy Beanka . Subfossil at Antsingimavo where it now appears to be locally extinct.

Habitat: Living specimens are most commonly found amongst limestone rocks and in leaf-litter. In Tsingy Beanka , it occurs predominantly in the taller, moister forests of the southern part.

Remarks: Shell lenticular, of moderate size (max. diameter <33 mm), with a very low spire and sharply angled periphery; last whorl descending at most slightly just prior to aperture; uniformly tan-brown with a yellow to white band around umbilicus. Specimens from Tsingy Beanka are noticeably smaller than those from Bemaraha and Antsingimavo (maximum adult diameter 20–25 vs 28–32 mm).

Resembles A. namerokoensis (below) in size and shape, but easily separated from that species due to the almost complete absence of microscopic spiral striae (some traces may be visible on the base). Instead the microsculpture of A. milloti comprises irregular, elongate granules aligned in a roughly radial (collabral) pattern ( Fig. 17D ). Furthermore, A. milloti attains a somewhat larger size and has a wider umbilicus than A. namerokoensis , and its protoconch is larger (diameter approx. 4.4 vs approx. 3.5 mm) and bears distinct close-set axial riblets ( Fig. 17C ), whereas that of A. namerokoensis is more or less smooth ( Fig. 17E ). Features separating A. milloti from A. beanka are discussed above.

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. 18. Ampelita milloti Fischer-Piette, 1952, Tsingy Beanka, st’n 16/06, max. diameter 24.8 mm, NMSA L7127.

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.