Natalina quekettiana montistempli, Herbert & Moussalli, 2010

Herbert, D. G. & Moussalli, A., 2010, Revision of the larger cannibal snails (Natalina s. l.) of southern Africa - Natalina s. s., Afrorhytida and Capitina (Mollusca: Gastropoda: Rhytididae), African Invertebrates 51 (1), pp. 1-1 : 64-66

Natalina quekettiana montistempli subsp. n.

Figs 35E , 43–45

Etymology: From Latin mons (a mountain) and templum (a temple); with reference to Cathedral Peak.

Identification ( Fig. 44 ): For general description see Natalina q. quekettiana above. Although limited material is available it is evident that the shell of the living animal is paler and more uniformly coloured than in any of the other subspecies discussed above. The distinctive bicoloured pattern present in fresh, live-collected shells of the other subspecies is not evident in N. q. montistempli , in which the apical and basal surfaces are more or less the same colour even in fresh, live-collected shells ( Figs 44A–C ). In terms of the pale shell colour it resembles N. reenenensis , but in that taxon the radula has only five lateral teeth per half row, compared to eight in N. q. montistempli (acknowledging that for both taxa details of radula dentition are known for very few specimens).

Dimensions: Holotype (largest specimen), diameter 28.0 mm, height 14.4 mm; H:D of adults 0.51–0.62 (N=9).

Living animal (information available for only one animal) ( Fig. 35E ): Dorsal region of head-foot dark grey, lacking paler longitudinal stripes on neck; tentacles somewhat darker; sides of foot progressively paler toward pedal margin, the latter not distinctively coloured, whitish beneath shell; mantle edge very pale, almost white; lung wall with some rather diffuse black pigmentation, particularly associated with blood vessels, but not heavily blotched.

Radula ( Fig. 45 ): Formula 1+8+(14–18) (N=4); length up to 20.4 mm, with up to 71 broadly V-shaped rows of teeth.

Distal genitalia: Epiphallus structure typical of N. quekettiana ; a bulla is not evident.

Spermatophore: Unknown. Epiphallus structure suggests that the anterior two-thirds will bear well-developed scale-like spines.

Holotype ( Figs 44A–C ): SOUTH AFRICA: KZN: Fern Forest (Oqalweni Forest), Cathedral Peak area, (28.94329°S: 29.18580°E), 1531 m, montane Podocarpus forest, in leaf-litter, D. Herbert, Earthwatch, 19/ iii/2006 ( NMSA W4084 /T2422).

Paratypes: SOUTH AFRICA: KZN: same data as holotype ( NMSA W6653 /T2428, 4 adults and 3 juveniles; W5095/T2449, 1 specimen); Cathedral Peak area, Oqalweni Forest (28.94265°S: 29.18941°E), 1552 m , indigenous forest, in leaf-litter, M. Hamer et al., 19/iii/2006 ( NMSA W5093 /T2448, 1 specimen); ditto, Oqalweni Forest (28.9422°S: 29.1814°E), 1600 m , montane Podocarpus forest, in leaf-litter, A.C. & W.H. van Bruggen, 05/iv/1962 ( NMSA B0044 /T2447, 1 specimen); ditto, Rainbow Gorge (28.95813°S: 29.22070°E), 1550 m , montane Podocarpus forest, in leaf-litter, C. Uys, 06/i/2005 ( NMSA W2605 /T2446, 1 specimen; W4596/T2430, 4 specimens); ditto, Rainbow Gorge (28.96051°S: 29.22455°E), 1518 m , indigenous forest, in leaf-litter, M. Hamer et al., 12/iii/2006 ( NMSA W5091 /T2445, 2 specimens, crop contents included partially digested earthworms, Proandricus sp ); ditto, Rainbow Gorge (28.96012°S: 29.22520°E), 1600 m , montane Podocarpus forest, in leaf-litter, C. Uys, 05/i/2005 ( NMSA W2591 /T2444, 1 specimen); ditto, Ndumeni Forest (28.961°S: 29.222°E), 1550 m , under logs and rocks, C. Griswold, 22/ii/ 1984 ( NMSA V7745 /T2432, 1 specimen); ditto, Ndumeni Forest (28.961°S: 29.224°E), 1550 m , under stone at foot of krantzes, A.C. & W.H. van Bruggen, 03/iv/1962 ( NMSA V5205 /T2431, 1 specimen); Cathedral Peak area , 1540 m , montane Podocarpus forest, R. Kilburn, 21/i/1984 ( NMSA V2148 /T2429, 1 specimen). Distribution ( Fig. 43 ): Known only from the Cathedral Peak area in the KZN Drakensberg; occurs at altitudes of 1500–1600 m .

Habitat: Afrotemperate forest, in leaf-litter.

Notes: As with Natalina q. dracomontana , we describe this material as a new taxon largely on account of molecular data ( Moussalli et al. 2009) which indicate it to comprise a deeply divergent lineage within the N. quekettiana complex. However, although few adult specimens are available, there is also some evidence that the shell coloration is also distinctive.

This occurrence of a distinctive lineage of land snail in the Cathedral Peak area is mirrored by two achatinid species Cochlitoma montistempli ( Bruggen, 1965) and C. omissa ( Bruggen, 1965) . It strongly suggests that this region of the Drakensberg has been subject to historical environmental conditions that have resulted in the long-term isolation and independent evolution of a distinctive and perhaps now relictual fauna of narrow-range endemics. Similar narrow-range endemism is found in the chameleon fauna of the Drakensberg ( Tolley & Burger 2007) (see also biogeographic summary below).

Conservation: On account of its very limited distribution (known extent of occurrence is less than 3.0 km 2) Natalina q. montistempli is clearly a taxon of conservation concern. It occurs in a formally protected region (the uKhahlamba Drakensberg World Heritage Site ) where disturbance is limited, but it is evident that the forests of the Cathedral Peak area harbour a fauna of particular interest and that they should be managed so as to keep disturbance to a minimum. Burning practices in the surrounding grasslands need to be particularly carefully managed.

Figures

Fig. 35. Natalina quekettiana complex, living animals and eggs (all NMSA):(A) N. q. quekettiana, Ferncliffe, Pietermaritzburg (W6646), shell diameter 31.3 mm; (B) N. q. lucaris subsp. n., Ngome Forest (paratype, V2249/T2563), shell diameter 29.4 mm; (C) N. q. dracomontana subsp. n., Injasuthi (holotype, V7992/T2451), shell diameter 27.2 mm; (D) N. q. dracomontana subsp. n., Monk’s Cowl area (paratype, W4101/T2452), shell diameter 26.4 mm; (E) N. q. montistempli subsp. n., Oqalweni, Cathedral Peak (holotype, W4084/T2422), shell diameter 23.9 mm; (F) N. q. quekettiana, eggs (W6646), scale in millimetres.

Fig. 43. Distribution of Natalina quekettiana dracomontana subsp. n. (squares), N. q. montistempli subsp. n. (triangles) and N. reenenensis Connolly, 1939 (circles). Symbols with a white centre indicate localities for specimens used in DNA analyses (Moussalli et al. 2009); contours at 1000 m and 1500 m.

Fig. 44. Natalina quekettiana montistempli subsp. n.: (A–C) holotype, diameter 28.0 mm (NMSA W4084/ T2422); (D) paratype from type locality, diameter 27.8 mm (NMSA W6653/T2428).

Fig.45. Natalina quekettiana montistempli subsp. n., radula (holotype NMSA W4084/T2422):(A) rachidian and lateral teeth, scale bar = 0.5 mm; (B) vestigial marginal teeth, scale bar = 100 µm.