Cumberlandica, Shea & Colgan & Stanisic, 2012

Shea, M., Colgan, D. J. & Stanisic, J., 2012, 3585, Zootaxa 3585, pp. 1-109 : 23-24

Cumberlandica n. gen.

Gyrocochlea Hedley, 1924: 215 (in part); Iredale 1937: 322 (in part); Iredale 1941a: 267 (in part); Smith 1992: 190 (in part); Stanisic et al. 2010: 196 (in part).

Type species. Gyrocochlea impressa Hedley, 1924 —here designated.

Etymology. Named for the County of Cumberland, Sydney, which is at the centre of the distribution of the genus.

Diagnosis. Shell very small, brown with a deeply biconcave to almost flat spire, and tightly and evenly coiled whorls. Protoconch sculpture of many, widely spaced spiral cords and curved radial ribs that form on its latter part, becoming more pronounced toward the teleoconch boundary; teleoconch sculptured with numerous well developed, widely spaced radial ribs; microsculpture cancellate consisting of fine microradial ribs and low microspiral cords. Umbilicus wide U-shaped to cup-shaped. Epiphallus as long as penis; penis pear-shaped with apical verge and long tapering distal portion; penial verge large, open and convoluted with a lateral slit; longitudinal pilasters distally; vagina long.

Distribution and habitat. Sydney Basin, specifically the Hawkesbury-Nepean drainage, between Terrigal in the north, Mt Wilson in the upper Blue Mountains in the west and the Wombeyan limestones in the south; found in subtropical to warm temperate rainforest, moist sclerophyll forest, dry or littoral vine thicket, living on the underside of logs, wood and rocks, often in groups.

Remarks. Cumberlandica n. gen. is endemic to the Sydney Basin. It is readily distinguished from Gyrocochlea s.s. by (1) its bi-modal protoconch sculpture (spiral lirae at the beginning and radial ribs toward the end)— Gyrocochlea s.s. having only very finely cancellate sculpture. (2) more evenly coiled whorls—the last whorl greatly expanded in Gyrocochlea s.s. and (3) and a more widely open umbilicus. Diphyoropa Hyman & Stanisic, 2005 has a grossly similar bi-modal protoconch sculpture, however in this genus the spirals are much bolder and more widely spaced and the radials less prominent, low ridges. Cumberlandica is distinguished from the broadly sympatric Planorbacochlea n. gen. by the protoconch sculpture (finely spiral in the latter) and in having a larger shell ( Table 3) with more numerous and more evenly coiled whorls. Anatomically, the characteristic features of Cumberlandica are the elongate pallial wall, numerous long finger-like alveoli, large prominent talon, tightly entwined epiphallus/penial retractor, broad oval or pear shaped penis with long tapering distal portion, large open and convoluted penial verge and long vagina.

The inclusion of Cu. wilsoniana n. sp. in the genus is tentative and subject to further investigation. An SEM of the protoconch was not taken but optical microscopy revealed a pattern of radial ribs and very weak spirals. The protoconch sculpture specifically (prominent radial ribs and weak spirals), coiling pattern and aperture shape of this species are not representative of the general patterns displayed by other Cumberlandica species. No soft parts of this species were available for anatomical or molecular studies. Given its refugial, mountain-top existence, this species may eventually be shown to represent a new genus.