Elatonitor suturalis ( Odhner, 1917 )

Hyman, Isabel T. & Köhler, Frank, 2022, Homoplasy in shells discombobulated the taxonomy: revision of the larger helicarionid land snails of northern Queensland, Australia (Stylommatophora: Helicarionidae), Journal of Natural History 56 (41 - 44), pp. 1727-1799 : 1792-1796

Elatonitor suturalis ( Odhner, 1917)

( Figures 4 , 7 (g–i), 8(f), 22(b), 24)

Macrochlamys suturalis Odhner, 1917: 81 , figs 35b, 36–38.

Macrochlamys suturalis depressa Odhner, 1917: 81 .

Malandena suturalis: Iredale 1933: 56 ; Iredale 1937 c: 7; Smith, 1992: 236; Hyman and Ponder 2010: 67–68, figs 19 K, 20 J, 21 K, 22E, 24A, 25A–C; Stanisic et al. 2010: 296– 297, 326.

Synonymy follows Smith (1992).

Material examined

Lectotype. NHRM SMNH Type-9346. Malanda, N Qld, Australia.

Paralectotypes. NHRM 950 (Malanda, N Qld, 3 specimens), NHRM 6315 ( Cedar Creek , N Qld, 2 specimens), NHRM 6316 (Mt Bellenden Ker, N Qld, 1 specimen), NHRM 6317 (Herberton, N Qld, 2 specimens) .

Syntype of Macrochlamys suturalis depressa . NHRM 939 . Cairns and Atherton, N Qld, 1 specimen.

Diagnosis

External morphology. Shell ( Figures 7 (g–i), 22(b)) medium-sized to large (SW 15.3–20 mm), pale amber, often deep amber below periphery, coloured reddish brown at suture and around umbilicus, 5.3–5.8 whorls, depressedly globose with a moderately raised spire, whorl profile rounded above and below a mildly angulate periphery; microsculpture of very fine (almost obsolete) spirals on protoconch, and coarser, more distinct spirals on teleoconch; umbilicus very narrow. Body ( Figure 8 (f)) dark brown with black eyestalks. Mantle lobes moderately small; shell lappets long, narrow, tapering. Caudal horn large.

Genital anatomy. Genitalia ( Figure 24 ) with short vagina, internally sculptured with a network of wavy ridges; bursa copulatrix moderately long, duct narrow, slightly broader at base, internally with wavy transverse ridges at base, becoming longitudinal pilasters connected by tiny transverse ridges in most of duct; bursa oval. Penis long, tubular; internally with 2–4 longitudinal pilasters which sometimes merge or divide; internal wall sculptured with longitudinal ridges; penis enclosed in penial tunica. Epiphallus enters penis through a short verge; epiphallus longer than penis; epiphallus 2 approximately equal to epiphallus 1; epiphallic caecum absent; flagellum long, slender, without obvious internal cryptae. Spermatophore a soft-walled capsule with hard tail-pipe; capsule very elongate, with elongate tip; tail-pipe short, sculptured with short hooks, becoming more dense towards tip.

Remarks

In the original description of Elatonitor suturalis , this species was placed in the genus Macrochlamys and syntypes were designated from four separate locations in northern Qld (Malanda, Bellenden Ker, Cedar Creek and Herberton) ( Odhner 1917). The syntype material was examined in the current study, and the specimen that had been dissected and figured by Odhner (1917) is herein designated as a lectotype in accordance with Art. 74 of the International Code of Zoological Nomenclature ( ICZN 1999). This restricts the type locality to Malanda. The assignment of specimens to E. suturalis in the current study was confirmed by comparison with the dissected lectotype. Odhner’s (1917) figure agrees with the lectotype, but he mistakenly identifies the bursa copulatrix as the dart sac.

Elatonitor suturalis is recorded from rainforest and vine thicket from Cardwell Range to the Atherton Tablelands ( Stanisic et al. 2010); this range is confirmed in the present study ( Figure 4 ).

At the type locality, Malanda, it appears that both Pravonitor aquilonia and P. monteitshi are sympatric with E. suturalis . Both species bear a strong resemblance to E. suturalis , but can be distinguished by their much finer teleoconch sculpture, in contrast to the distinct and rather coarse spiral grooves seen on both the upper and lower shell surfaces in E. suturalis .

Figures

Figure 4. Distribution map. Grey symbols: Geminitor. Blue symbols: Pravonitor. Red symbols: Elatonitor. Biogeographic barriers are marked in black; A = Normanby Basin, B = Black Mountain Corridor, and C = Atherton Tableland.

Figure 7. Shell microsculpture. a–c). Geminitor laura, AM C.553551, Black Mountain. d–f). Pravonitor aquilonia, AM C.553561, SE of Malanda. g–i). Elatonitor suturalis, QM MO76507, NE of Babinda. Scale bars: b, e, h = 200 µm; a, c, d, f, g, i = 500 µm. Photographs by Sue Lindsay.

Figure 8. Live animal images. a). Geminitor laura, Black Mountain. b). Geminitor villaris. c). Pravonitor aquilonia, AM C.524931, Bellenden Ker. d). Pravonitor aquilonia, Cape Tribulation. e). Pravonitor aquilonia, AM C.524981, Mossman Gorge. f). Elatonitor suturalis, Wooroonooran NP. Images not to scale. Photographs by Adnan Moussalli (a, d, f), Frank Köhler (c, e) and Queensland Museum (b).

Figure 24. Genitalia of Elatonitor suturalis. a, c-d) AM C.524931, Wooroonooran NP. b) QM MO76507, Babinda. a) Reproductive system. b) Spermatophore. c) Penis interior. d) Details of the basal reproductive system. Scale bars: 1 mm.