Cumberlandica impressa impressa ( Hedley, 1924 ) impressa (Hedley, 1924

Shea, M., Colgan, D. J. & Stanisic, J., 2012, 3585, Zootaxa 3585, pp. 1-109 : 24-28

Cumberlandica impressa impressa ( Hedley, 1924) n. comb.

( Figs 7A – C, E; 8A – C, E; 9A – C, E; 10A – C, E; 11A, B, D, F; 12A, B, D; 13A, C, D; 14A – E)

Gyrocochlea impressa Hedley, 1924: 216 .

Gyrocochlea impressa: Iredale 1937: 323 ; Iredale 1941a: 268; Smith 1992: 191.

G. i. impressa

Diagnosis. Shell very small, brown, biconcave with tightly coiled whorls. Protoconch sculpture of low, widely spaced, narrow spiral cords, and widely spaced radial ribs, beginning on the final quarter of the protoconch and becoming more pronounced toward the protoconch-teleoconch boundary. Teleoconch sculpture of numerous, widely spaced radial ribs. Umbilicus widely open. Penis with apical tongue-shaped verge and longitudinal pilasters.

Type material examined. Neotype (here designated). AM C.463902, Bilpin Rest Area (Bilpin Park), Bells Line of Road , Bilpin, lower Blue Mountains, NSW (33° 29' 46.14” S, 150° 31' 02.86” E), on underside of logs in moist sclerophyll forest, 27.ix.2009, coll. M. Shea. [Damaged holotype (specimen crushed and consisting of tiny fragments). AM C.63499, Kurrajong, NSW (33° 33’ 17” S, 150° 39 42” E), 1891, C. T. Musson].

Other material examined. (All Sydney Basin, NSW) Bilpin: AM C.462733, AM C.463909. Freemans Reach: AM C.457178, AM C.462483, AM C.355262. Mulgoa: AM C.152188. Patonga: AM C.140234. McMasters Beach: QM unregistered, S.A. Clark coll. 9 July 1989 .

Description. Shell very small, cinnamon-brown, biconcave with deeply depressed spire. Whorls 4.1–5.0, tightly coiled, the last ascending, in line or descending in front. Sutures strongly impressed. Shell diameter 3.77–5.5 mm (mean 4.68 mm), height 2.18–3.11 mm (mean 2.55 mm), H/D 0.45–0.62 (mean 0.55). Protoconch flat, of 1.12–1.25 whorls, diameter 0.48–0.68 mm. Protoconch sculpture consisting of 15 to 27 low, widely spaced, narrow spiral cords and widely spaced, orthocline to prosocline radial ribs, beginning on the final quarter of the protoconch and 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 112–220 (mean 153), width of interstices on the first teleoconch whorl equal to width of four to greater than width of six ribs; on the penultimate whorl equal to width of three to greater than width of six ribs; each rib with two or more overlapping periostracal blades. Interstitial sculpture of low prominent microradial ribs and low, weaker microspiral cords forming beads at their intersection; number of microradials between ribs on the first teleoconch whorl 2–7; on first quarter of body whorl 6–10; microspirals very low. Aperture narrowly to broadly ovatelylunate. Parietal callus prominent, transparent. Umbilicus wide U-shaped to cup-shaped, diameter 1.09–1.93 mm (mean 1.50 mm), D/U 2.86–3.36 (mean 3.18). Based on 32 measured adults.

Reproductive organs with ovotestis containing two clumps of alveoli with more than two alveolar lobes per clump. Spermatheca with a medium sized oval bulb. Talon large, spherical or ovate. Penial retractor muscle less than half the length of penis, inserting at the junction of the penis and epiphallus. Epiphallus equal to the penis length, entering penis through a tongue-shaped verge opening through a lateral slit. Penis pear-shaped with an apical bulb, internally with longitudinal pilasters tapering to the atrium. Vagina shorter than penis.

Distribution and habitat. Central to lower Blue Mountains (Bilpin to Kurrajong) and east to Freemans Reach and Mulgoa on the Cumberland Plain, and the central coast, NSW; in eucalypt forest and vine thicket/dry rainforest in sheltered gullies living under logs, stumps, timber or rocks.

Remarks. The nominal subspecies differs from Cumberlandica impressa ponderi by the higher rib count and tighter whorl coiling and slightly narrower umbilicus. The two subspecies are strongly supported as reciprocally monophyletic in the ITS-2 analyses but not in COI analyses. Cu. wilsoniana has wider spaced radial ribs, a much more inflated body whorl with less laterally compressed aperture. Cu. wombeyanensis has more widely spaced teleoconch ribs (with every second rib enlarged), a narrower umbilicus, less sunken spire and more widely spaced radial ribs on the protoconch. The specimens of Cu. impressa impressa from Freemans Reach and Mulgoa have tighter whorl coiling than that of Bilpin.

Hedley’s original description of this species was based on a single specimen from Kurrajong in the lower Blue Mountains collected by C. T. Musson. This specimen is now badly damaged. Specimens that were collected for this study from Bilpin, which adjoins Kurrajong, and that closely agree with Hedley’s original description were used for the re-description here. A neotype was designated from this material. Stanisic et al. (2010) incorrectly figured and described a specimen ( QMMO42154 ) from Mt Wilson as this species mistakenly believing it to be conspecific with Hedley’s original description and illustration. That specimen is here given separate specific status as Cu. wilsoniana and its relationships are discussed below .