Comboynea mountaineer Shea & Colgan & Stanisic 2012, n. sp.

(Figs 29F; 31F; 33F; 35F)

Etymology. For the Mountaineer Trail.

Diagnosis. Shell very small, orange brown, biconcave with depressed spire. Protoconch sculpture primarily spiral consisting of 28 crowded, low, flattened, narrow spiral cords and faint, irregularly spaced, underlying radial ridges. Teleoconch sculpture of numerous, prominent, quite uniformly spaced, weakly sinuate, opisthocline radial ribs with a shallow sinus present at the suture junction. Ribs on body whorl 130 (mean 130). Umbilicus open, U-shaped.

Type material examined. Holotype. AM C.309160. Barrington Tops NP, Mountaineer Trail, ca 2 km from the beginning of the trail (at Forest Rd), New South Wales, (32° 7’ 10” S, 151° 40’ 12” E), 9. ii. 2002, coll. M. Shea, I. Hyman and C. Urquhart. Paratypes. AM C. 472878, same data as holotype.

Description. Shell very small, orange-brown, biconcave with depressed spire. Whorls 3.75–3.87, tightly coiled, the last inflated and descending in front. Sutures strongly impressed. Shell diameter 3.5–3.9 mm (mean 3.7 mm), height 1.93–2.24 mm (mean 2.09 mm), H/D 0.55–0.57 (mean 0.56). Protoconch flat, of 1.0 whorls, diameter 0.65 mm. Protoconch sculpture primarily spiral consisting of 28 crowded, low, flattened, narrow spiral cords and faint, irregularly spaced, underlying radial ridges. Teleoconch sculpture of numerous, prominent, quite uniformly spaced, weakly sinuate, opisthocline radial ribs with a shallow sinus present at the suture junction. Ribs on body whorl 130 (mean 130), width of interstices on the first teleoconch whorl equal to width of four to greater than or equal to width of six ribs; on the penultimate whorl equal to width of four to greater than or equal to width of six ribs; each rib with two or more periostracal blades. Interstitial sculpture of low, prominent microradial ribs and low, weaker microspiral cords forming weak beads at their intersection; number of microradials between ribs on the first teleoconch whorl 11–12; on first quarter of body whorl 7–10. Aperture, narrowly ovately-lunate. Parietal callus prominent, transparent. Umbilicus wide, U-shaped, diameter 0.86–0.93 mm (mean 0.89 mm), D/U 03.85–4.54 (mean 4.17). Based on 2 measured adults (one damaged).

Anatomy unknown.

Distribution and habitat. Barrington Tops NP, Mountaineer Trail, ca 2 km from the beginning of the trail (at Forest Rd); found in mixed beech, eucalypt and Callicoma forest, recovered from litter.

Remarks. Comboynea mountaineer n. sp. conchologically closely resembles Co. boorganna n. sp. from the Comboyne Plateau, differing mainly in the greater number of apical spiral cords. However, the montane distributions of the two species and the relative isolation of their localities make it highly unlikely that they are conspecifics. It is desirable to obtain live material of Co. mountaineer to test this hypothesis more fully through DNA studies.