Elatonitor Stanisic, 2010

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 : 1790-1791

Elatonitor Stanisic, 2010

Malandena Iredale, 1933: 56 [nom. nud.].

Malandena Iredale, 1937: 7 [nom. nud.].

Malandena Hyman and Ponder, 2010: 67 [nom. nud.].

Malandena Stanisic, 2010: 296 [nom. nud.].

Elatonitor Stanisic, 2010: 298 (of masculine gender).

Type species Elatonitor montanus Stanisic, 2010 .

Differential diagnosis

External appearance. Shell medium-sized to large (SW 13.9–20 mm), pale amber to amber, often deep amber below periphery, glossy, 5.3–5.8 whorls, depressedly globose to trochoidal with a moderate spire, whorl profile mildly to strongly angulate. Protoconch with very fine spiral grooves, sometimes becoming obsolete; teleoconch with very fine and dense to coarse, distinct spiral grooves. Body light to dark brown. Mantle lobes small to moderately small; shell lappets long, narrow, tapering. Caudal horn moderately large to large.

Genital anatomy. Ovotestis of 8–9 lobes, embedded in digestive gland. Carrefour visible; talon usually embedded in albumen gland. Spermoviduct not folded. Free oviduct long, with elongate capsular gland; free oviduct internally sculptured with longitudinal pilasters; capsular gland with no internal sculpture. Vagina short to long, sculptured internally with longitudinal pilasters or a network of wavy ridges. Bursa copulatrix inserted on the vagina, moderately short to moderately long, duct narrow, sometimes slightly broader at base, internally with primarily longitudinal sculpture; bursa elongate oval. Penis moderately small to long, tubular; internally with 2–4 longitudinal pilasters which sometimes merge or divide, internal wall sculptured with longitudinal wrinkles or ridges; penis and sometimes part of epiphallus enclosed in penial tunica. Epiphallus enters penis through a simple pore or a short verge; epiphallus longer than penis; epiphallus 2 equal to or longer than 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

Elatonitor was introduced for a single species, E. montanus , based on the sharply angulate whorls and very fine, very dense spiral sculpture of its shell. In the current study we demonstrate that there is a close relationship between E. montanus and Malandena suturalis , sole remaining member of genus Malandena . However, Malandena , while in current usage, has never been validly described and therefore remains unavailable ( Köhler and Bouchet 2020). Consequently, Elatonitor takes its place. Like all names ending in ‘nitor’, the genus name Elatonitor is of masculine gender.

Elatonitor is characterised by its medium-sized to large, glossy shell (shell 15–20 mm in width), depressedly globose to trochoidal shape with an angulate periphery and usually a supraperipheral band, and by anatomical features including the presence of at least a short vagina, a long, slender penis with longitudinal pilasters and longitudinal ridges or wrinkles, and an epiphallus with no caecum and with a slender flagellum. In particular, it can be distinguished from the similar genera Pravonitor and Geminitor by its large size, angulate shell periphery, the lack of an epiphallic caecum and the single-chambered penis with primarily longitudinal sculpture. This genus is found in rainforest and vine thicket from Mt Bartle Frere to Cooktown ( Stanisic et al. 2010).