Planorbacochlea watagan, Shea & Colgan & Stanisic, 2012

Shea, M., Colgan, D. J. & Stanisic, J., 2012, 3585, Zootaxa 3585, pp. 1-109 : 48-50

Planorbacochlea watagan n. sp.

( Figs 15E; 16E; 17E; 18D; 19E)

Etymology. Named for the Watagans Mountains, west of Lake Macquarie, NSW.

Diagnosis. Shell very small, light brown, biconcave with weakly depressed spire. Protoconch sculpture strongly spiral consisting of 22 prominent, closely spaced, beaded spiral cords; and weak, closely spaced radial ridges becoming more pronounced toward the protoconch-teleoconch boundary. Teleoconch sculpture of numerous, prominent, quite uniformly spaced, slightly sinuate, orthocline radial ribs. Ribs on body whorl 174–228. Umbilicus open, U-shaped.

Type material examined. Holotype. AM C.309158, Olney State Forest, at The Basin camping area, upper Wollombi Brook , Watagan Mountains , SW of Newcastle, NSW (33° 06’ 14” S, 151° 13' 46” E), 16.i.2000, coll. M. Shea. Paratypes. AM C.472886, same data as holotype. Wyong State Forest : AM C.162128, AM C.319715, AM C.319920 (33° 13’ 58”'S, 151° 20’ 23” E). Watagan National Park : AM C.309157 (33° 50’ 0” S, 151° 26’ 01” E) .

Description. Shell very small, light brown, biconcave with weakly depressed spire. Whorls 3.0–3.75, tightly coiled, the last inflated and descending in front. Sutures strongly impressed. Shell diameter 2.87–3.42 mm (mean 3.25 mm), height 1.56–1.79 mm (mean 1.66 mm), H/D 0.49–0.56 (mean 0.51). Protoconch flat, of 1.25 whorls, diameter 0.45–0.58 mm. Protoconch sculpture strongly spiral consisting of 22 prominent, closely spaced, beaded spiral cords and weak, closely spaced radial ridges becoming more pronounced toward the protoconch-teleoconch boundary. Teleoconch sculpture of numerous, prominent, quite uniformly spaced, slightly sinuate, orthocline radial ribs. Ribs on body whorl 174–228 (mean 188), width of interstices on the first teleoconch whorl equal to width of three to less than six ribs; on the penultimate whorl equal to width of three to less than six ribs; each rib with two or more periostracal blades with overlapping thickenings. 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 4–6; on first quarter of body whorl 4–7; height of microspirals variable. Aperture broadly ovately-lunate. Parietal callus prominent, transparent. Umbilicus open, U-shaped, diameter 0.81–1.06 mm (mean 0.85 mm), D/U 3.24–3.74 (mean 3.62). Based on 6 measured adults.

Anatomy unknown.

Distribution and habitat. Wyong-Watagan Mountains district, west of Wyong and Lake Macquarie, NSW; in subtropical rainforest to understorey vine thicket in sclerophyll forest, in litter, under logs and rocks.

Remarks. Planorbacochlea watagan n. sp. differs from P. hawkesburyana by having fewer spiral cords on the protoconch and more numerous radial ribs on the teleoconch.