Cremnoconchus hanumani, Reid & Aravind & Madhyastha, 2013

Reid, David G., Aravind, Neelavara Ananthram & Madhyastha, Neelavara Ananthram, 2013, A unique radiation of marine littorinid snails in the freshwater streams of the Western Ghats of India: the genus Cremnoconchus W. T. Blanford, 1869 (Gastropoda: Littorinidae), Zoological Journal of the Linnean Society 167 (1), pp. 93-135 : 118-121

CREMNOCONCHUS HANUMANI SP. NOV.

( FIGS 4N, O , 5I, J, 7G, H, 8, 11A–G, 12A–G)

Types: Holotype ZSI / WGRS /IR.INV-2303 (Fig. 11A, B); 1 paratype ZSI / WGRS /IR.INV-2304 (Fig. 11C); Hanuman Gundi Falls , Chikmagalur Dist., Karnataka, India (13.27008°N 75.15511°E).

Etymology: After the Hindu deity Hanuman, from the type locality.

Diagnosis: Shell turbinate to globular, without ribs; pseudumbilicus broad but not perforated; surface with satin sheen, faint microstriae. Operculum weakly calcified, no internal ridge. Penis with slight distal swelling, stout filament. Western Karnataka State.

Shell ( Figs 4N, O , 11A–G): Shell H 3.3–5.0 mm. Shape ( Table 1) globular to turbinate; whorls rounded, not or only slightly angled at periphery; suture impressed, with slightly flattened ramp and weakly angled shoulder; apex eroded; base slightly swollen. Delicate texture. Columella narrow. Pseudumbilicus broad (to 1.0 mm; rarely 0.3–0.5 mm), hollowed but not deeply perforated, outlined by sharply angled margin continuous with apertural margin (Fig. 11B). Surface without ribs; with satin sheen; very fine or faint spiral striae ( Fig. 4N, O ), becoming obsolete on last whorl of largest shells. Protoconch 1.4 whorls; diameter 0.62 (N = 1); diameter of first whorl 0.45– 0.53 mm (N = 2). Colour: dark brown or olive-brown,

› Figure 11. Shells of Cremnoconchus species. A –G, C. hanumani . H–L, C. globulus . M–P, C. agumbensis . Q–U, C. cingulatus . V–AA, C. castanea . BB–EE, C. dwarakii . A–C, C. hanumani sp. nov., holotype (A, B; ZSI/WGRS/IR.INV-2303) and paratype (C; ZSI/WGRS/IR.INV-2304), Hanuman Gundi Falls, Chikmagalur Dist., Karnataka. D–G, Greater Kadambi Falls, Chikmagalur Dist., Karnataka (D, E two views of same specimen; ZSI/WGRS/IR.INV-2305, 2306, 2307). H, L, Greater Kadambi Falls, Chikmagalur Dist., Karnataka (ZSI/WGRS/IR.INV-2308, 2309). I–K, C. globulus sp. nov., holotype (I, J; ZSI/WGRS/IR.INV-2310) and paratype (K; ZSI/WGRS/IR.INV-2311), Lesser Kadambi Falls, Chikmagalur Dist., Karnataka. M–P, C. agumbensis sp. nov., holotype (M, N; ZSI/WGRS/IR.INV-2313) and paratypes (O, P; ZSI/WGRS/IR.INV-2314, 2315), Someshwara to Agumbe road, Udupi Dist., Karnataka. Q–U, C. cingulatus sp. nov., holotype (R, S; ZSI/WGRS/IR.INV-2316) and paratypes (Q, T, U; ZSI/WGRS/IR.INV-2317, 2318, 2319), Hulikal Ghat, Udupi Dist., Karnataka. V–X, C. castanea sp. nov., holotype (W, X; ZSI/WGRS/IR.INV-2321) and paratype (V; ZSI/ WGRS/IR.INV-2320), Belkal Thirtha Falls, Udupi Dist., Karnataka. Y, Arasinagundi Falls, Udupi Dist., Karnataka (BMNH 20120032). Z, AA, no locality (two views of same specimen; ZSI/WGRS/IR.INV-2322). BB–DD, C. dwarakii sp. nov., holotype (BB, CC; ZSI/WGRS/IR.INV-2323) and paratype (DD; ZSI/WGRS/IR.INV-2324), Hulikal Ghat, Udupi Dist., Karnataka. EE, Hulikal Ghat, Udupi Dist., Karnataka (BMNH 20120036).

sometimes a narrow purple-brown band at suture; columella whitish or slightly tinged purple-brown; aperture pale with sutural band showing through.

Animal: Head, tentacles, and sides of foot dark grey to black. Gills: 24–30 leaflets; grey or unpigmented. Operculum ( Table 1; Fig. 5I, J): opercular ratio 0.318 – 0.400; weakly calcified, translucent mid-brown, no internal ridge. Penis ( Fig. 12A–G ): unpigmented or slightly pigmented; base wrinkled, slightly swollen (possibly glandular) distally; invagination 70–90% of length of base in ethanol-fixed specimens; filament relatively stout, usually protruding in ethanol-fixed specimens. Pallial oviduct: as for genus. One pallial oviduct contained single egg with firm covering 0.47 mm diameter (ethanol fixed).

Radula ( Fig. 7G, H ): Relative radula length 2.50– 3.06. Rachidian: length/width 1.09–1.21; 5 cusps (+ 1 outer denticle on either side). Lateral: 5 cusps (+ 1–2 inner denticles). Inner marginal: 6 cusps. Outer marginal: 6–7 cusps (+ 1 inner or outer denticle). Major cusp of each of 5 central teeth leaf-shaped with pointed tip; other cusps pointed.

Range ( Fig. 8 ): Western Karnataka State, Kudremukh (55 km north-east of Mangalore). Records (Supporting Table S1): Karnataka State: Hanuman Gundi Falls (ZSI/WGRS/IR.INV-2303, 2304); Greater Kadambi Falls (ZSI/WGRS/IR.INV-2305, 2306, 2307).

Habitat and ecology: On rocks and cliff wetted by spray from strong waterfall; in crevices; in partial

shade of riparian vegetation in wet evergreen forest. Altitude 830 m and 941 m.

Remarks: The small, globose shell with delicate texture and wide (but not perforated) pseudumbilicus are distinctive of this species. Cremnoconchus castanea has a taller, thicker shell and well-calcified operculum ( Table 4). Cremnoconchus globulus can be found together with C. hanumani (Supporting Table S1); the former is larger, more solid, with a moderate umbilicus; the operculum is weakly calcified in both, but dark red-brown in C. globulus and translucent mid-brown in C. hanumani . The penis of C. hanumani is diagnostic.

Where this species occurs in the same stream as the larger C. globulus there is no obvious difference in microhabitat.

Figures

Figure 4. Microsculpture of Cremnoconchus species (viewed by SEM). A, C. dwarakii, Hulikal Ghat, Udupi Dist., Karnataka. B, C. syhadrensis, Matheran, Raigad Dist., Maharashtra. C, C. syhadrensis, Khandala, Pune Dist., Maharashtra. D, C. conicus, 44 km west of Bhor, Pune Dist., Maharashtra. E, C. conicus, 6 km west of Mahabaleshwar, Satara Dist., Maharashtra. F, C. globulus, Lesser Kadambi Falls, Chikmagalur Dist., Karnataka. G, C. cingulatus, Hulikal Ghat, Udupi Dist., Karnataka. H, C. agumbensis, Agumbe, Udupi Dist., Karnataka. I, C. canaliculatus, 10 km west of Mahabaleshwar, Raigad Dist., Maharashtra. J, C. canaliculatus, Dongarwadi, Tamhini, Pune Dist., Maharashtra. K, C. canaliculatus, 5 km south of Mahabaleshwar, Satara Dist., Maharashtra. L, C. castanea, Belkal Thirtha Falls, Udupi Dist., Karnataka. M, C. castanea, Arasinagundi Falls, Udupi Dist., Karnataka. N, C. hanumani, Greater Kadambi Falls, Chikmagalur Dist., Karnataka. O, C. hanumani, Hanuman Gundi Falls, Chikmagalur Dist., Karnataka.

Figure 7. Radulae of Cremnoconchus species (two views of each radula, flat and at 45°). A, B, C. syhadrensis, Matheran, Raigad Dist., Maharashtra (ZSI/WGRS; shell H = 7.0 mm). C, D, C. conicus, 6 km west of Mahabaleshwar, Satara Dist., Maharashtra (ZSI/WGRS; shell H = 4.9 mm). E, F, C. canaliculatus, 10 km west of Mahabaleshwar, Raigad Dist., Maharashtra (ZSI/WGRS; shell H = 9.3 mm). G, H, C. hanumani, Greater Kadambi Falls, Chikmagalur Dist., Karnataka (ZSI/WGRS; shell H = 5.0 mm). Scale bars = 50 Mm.

Figure 8. Distribution of Cremnoconchus species (solid circles). Two or more species names (e.g. syhadrensis + canaliculatus) indicate sympatric occurrence. See Supporting Table S1 for locality details. The shaded area is the Western Ghats region as defined by Irfan-Ullah & Davande (2008). Cities indicated by asterisks.

Figure 12. Anatomy of Cremnoconchus hanumani (A–G) and C. globulus (H–L), all to same magnification. A–L, penes (all fixed in ethanol); F, G are intact and sectioned views of same penis. A–C, Hanuman Gundi Falls, Chikmagalur Dist., Karnataka (ZSI/WGRS; shell H: A = 4.9 mm; B = 3.5 mm; C = 3.3 mm). D–G, Greater Kadambi Falls, Chikmagalur Dist., Karnataka (ZSI/WGRS; shell H: D = 3.9 mm; E = 4.0 mm; F, G = 5.0 mm). H–K, Lesser Kadambi Falls, Chikmagalur Dist., Karnataka (ZSI/WGRS; shell H: H = 7.0 mm; I = 6.0 mm; J = 7.0 mm; K = 6.3 mm). L, Greater Kadambi Falls, Chikmagalur Dist., Karnataka (ZSI/WGRS; shell H = 7.9 mm). Shading conventions as in Figure 6.