Natalina quekettiana lucaris, 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 : 59-61

Natalina quekettiana lucaris subsp. n.

Figs 10E , 11C, D , 12C , 14F , 35B , 38–40

Etymology: From Latin lucus (a sacred grove or forest); in reference to the many traditionally sacred sites within the forests of central and southern Zululand, in particular Ngome and Nkandla Forests.

Identification ( Fig. 39 ): For general description see N. q. quekettiana above. Attains a larger size than any of the other taxa in the N. quekettiana complex (adult diameter> 35 mm); spire frequently also more elevated and periphery close to mid-whorl; axial riblets usually remaining distinct on base, but not always so; radula with six pairs of lateral teeth per transverse row.

As in N. q. quekettiana , fresh specimens have a darker brown apical surface and frequently a distinctly greenish base, but the contrast fades to a less intense yellowish brown and olive-green with time.

Dimensions: Holotype: diameter 38.4 mm, height 27.1 mm; largest specimen (W1114/ T2562, Nkandla Forest), diameter 43.0 mm; H:D of adults 0.58–0.71 (N=11).

Living animal ( Fig. 35B ): Head-foot dark grey-black dorsally, sides of foot paler; neck region lacking paler, dorsolateral, longitudinal stripes; tentacles dark grey-black; margin of foot fringed with yellow or orange-yellow, mantle edge bright sulphur-yellow to orange; lung wall usually heavily mottled with dots and anastomosing blotches of black pigmentation.

Radula ( Fig. 40 ): Like that of Natalina q. quekettiana , but with fewer transverse rows and only six lateral teeth per half row; formula 1+6+(17–20) (N=6, one in BMNH, Piele coll.); length up to 34 mm, with 49–66 broadly V-shaped transverse rows of teeth.

Distal genitalia: As for Natalina q. quekettiana .

Spermatophore ( Figs 12C , 14F ): Described and illustrated above in discussion of generic characters. Holotype ( Figs 39A–C ): SOUTH AFRICA: KZN: Entumeni Nat. Res. , (28.88836°S: 31.38007°E), 620 m,

scarp forest, under log, A. Moussalli & D. Stuart-Fox, 24/xii/2003 (NMSA W3310/T2557).

Paratypes: SOUTH AFRICA: KZN: Ngome Forest (27.827°S: 31.415°E), 1200 m, mist-belt Podocarpus forest, dead under log near camp site, D. Herbert, 19/i/1995 ( NMSA V657 /T2560, 1 specimen) ; Ngome Forest , Ntendeka wilderness area (27.80177°S: 31.43765°E), 1100 m, mist-belt forest, in leaf-litter, A. Moussalli & D. Stuart-Fox, 08/i/2004 ( BMNH 20100125 , 1 specimen; NMSA W3128 /T2566, 3 specimens; W3305/T2559, 5 specimens; W3306/T2564, 2 juvenile specimens) ; Ngome Forest (27.8281°S: 31.4190°E), 1110 m, mist-belt section of forest, mostly under logs, D. Herbert, 14/xii/1995 ( NMSA V2249 /T2563, 6 specimens) ; Nkandla Forest Res., Chibini area (28.7227°S: 31.1282°E), 1200 m, mist-belt forest, under logs and in leaf-litter, D. Herbert, M. Bursey & T. Nangammbi, 20/x/2003 ( NMSA W1114 /T2562, 2 specimens) ; same data as holotype ( NMSA W6854 /T2558, 1 specimen; W3317/T2565, 2 juvenile specimens) ; Entumeni Nat. Res. (28.883°S: 31.383°E), 700 m, scarp forest, in leaf-litter, O. Bourquin, vii/ 1981 ( NMSA B5290 /T2561, 1 specimen) ; Entumeni Nat. Res. (28.88583°S: 31.37944°E), 663 m, scarp forest, in leaf-litter at base of large tree between forestry office and picnic site, M. & K. Cole, 13/i/2010 ( ELM D16217 /T027, 1 specimen) ; Kranskop , Zimbaba Bush (28.9328°S: 30.9510°E), 1100 m, 1922 ( NMSA A7060 /T2568, 1 juvenile specimen; A7061/T2567, 2 juvenile specimens; A7135/T2569, 1 specimen) .

Distribution ( Fig. 38 ): Known primarily from the interior of Zululand (Ngome, Nkandla and Entumeni forests), but extending across the Thukela River valley to the Kranskop area; occurs at altitudes of 600–1200 m.

Habitat: Restricted to Afrotemperate and scarp forest; in leaf-litter and under logs; evidently scarce.

Notes: Molecular data indicate this subspecies to be the sister taxon of the nominotypical subspecies ( Moussalli et al. 2009), which it resembles in terms of the bicoloured shell pattern in living specimens and the very dark head-foot coloration. It differs in attaining a considerably larger size and in having only six lateral teeth per half row in the radula, compared to 8 or 9 in N. q. quekettiana .

Some variation in coloration, possibly geographical, is evident. Specimens from Ngome Forest have a distinctly bicoloured shell with a dark brown apical surface, whereas in those from Entumeni Forest the shell is less strongly bicoloured, with a chestnut to tan apical surface, and the mantle edge and pedal margin are orangish rather than bright yellow.

Conservation: The known extent of occurrence of N. q. lucaris is approx. 2500 km 2, but within this range its distribution is limited to islands of mist-belt and scarp forest. The forests from which it has been recorded include some of the largest such habitats remaining in KwaZulu-Natal (>2750 ha), and it is likely also to occur in Qudeni Forest, another large but very poorly sampled forest. These forests are in some cases formally protected, but the level of protection is variable and its efficacy is not guaranteed. Owing to their remote location in underdeveloped areas, the forests are subject to on-going anthropogenic pressure in the form of subsistence harvesting of forest products, grazing and trampling by livestock, and peripheral encroachment by small-scale agriculture.

Figures

Fig. 10. Spermatophores of Capitina, Afrorhytida and Natalina (all NMSA):(A) C. calcicola sp. n. (paratype, W5670/T2265), length 8.2 mm; (B) A. burseyae sp. n. (paratype, W5231/T2260), length 10.5 mm; (C) A. kraussi kraussi (W5803), length 20 mm; (D) N. cafra natalensis subsp. n. (paratype, E7682/T2375), length 16.3 mm; (E) N. quekettiana lucaris subsp. n. (paratype, W3305/T2559), length 26.5 mm; (F) N. wesseliana (V7668), length 32 mm. The head of the spermatophore is uppermost in all cases and the lengths given are for the spermatophore as if straightened out.

Fig. 11. Suprapedal glands of Capitina, Afrorhytida and Natalina (all NMSA): (A) C. schaerfiae (W5672), scale bar = 5.0 mm; (B) A. knysnaensis (W3351), scale bar = 5.0 mm; (C, D) N. quekettiana lucaris subsp. n. (W3310): (C) pedal cavity with suprapedal gland in situ, scale bar = 10 mm; (D) dissected gland, scale bar = 5.0 mm; (E, F) N. wesseliana (V7668): (E) entire gland, scale bar = 20 mm; (F) enlargement of distal end showing terminal vesicle, scale bar = 5.0 mm; (G) N. cafra cafra (W4220), scale bar = 10 mm. Abbreviations: asg – aperture of suprapedal gland, pa – pedal artery, v – vesicle at posterior end of suprapedal gland.

Fig. 12. Natalina s.s. genital system: (A, B) N. cafra natalensis subsp. n. (paratype, NMSA E7682/T2375): (A) entire reproductive tract, scale bar = 10 mm; (B) oviduct caecum (with spermatophore), teased away from free oviduct, scale bar = 5.0 mm; (C) N. quekettiana lucaris subsp. n. (paratype, NMSA W3305/T2559), oviduct caecum (with spermatophore) twisted around free oviduct and base of spermoviduct, scale bar = 5.0 mm.Abbreviations: ag – albumen gland, bc – bursa copulatrix, bd – bursa copulatrix duct, ep – epiphallus,fod – free oviduct,ga – genital atrium, hd – hermaphrodite duct, oc – oviduct caecum, ot – ovotestis, p – penis, pr – penial retractor muscle, s – spermatophore, sod – spermoviduct, v – vagina, vd – vas deferens.

Fig. 14. Natalina s.s. spermatophores (all NMSA): (A) N.cafra amathole subsp. n. (W4193), length 21 mm; (B) N. cafra natalensis subsp. n. (W7136), length 18.3 mm; (C) N. cafra eumacta (W4055, Manubi Forest), distorted spermatophore with finger-like process on tail region, length 12 mm; (D) N. c. eumacta (W4160, Manubi Forest), well preserved spermatophore lacking finger-like process on tail region, length 18.5 mm; (E) N. beyrichi (W4123), length 25.8 mm; (F) N. quekettiana lucaris subsp. n. (paratype, W3305/T2559), length 26.5 mm. The lengths given are for the spermatophore as if straightened out.

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. 38. Distribution of Natalina quekettiana quekettiana (Melvill & Ponsonby, 1893) (squares), N.q. lucaris subsp. n. (triangles) and Natalina inhluzana (Melvill & Ponsonby, 1894) (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. 39. Natalina quekettiana lucaris subsp. n. (all NMSA): (A–C) holotype (W3310/T2557), diameter 38.4 mm; (D) paratype, Ngome Forest (W3305/T2559), diameter 37.5 mm; (E) subadult paratype, Ngome Forest (W3305/T2559), diameter 34.9 mm; (F) largest paratype, Nkandla Forest (W1114/ T2562), diameter 43.0 mm.

Fig. 40. Natalina quekettiana lucaris subsp. n., radula (paratype, NMSA W3305/T2559): (A) rachidian and lateral teeth, scale bar = 0.5 mm; (B) vestigial marginal teeth, scale bar = 100 µm.