Gyrocochlea Hedley, 1924

Shea, M., Colgan, D. J. & Stanisic, J., 2012, 3585, Zootaxa 3585, pp. 1-109 : 85-86

Gyrocochlea Hedley, 1924

Gyrocochlea Hedley, 1924 (in part); Iredale 1937: 322 (in part); Iredale 1941a: 267 (in part); Stanisic 1990: 77; Smith 1992: 190 (in part); Stanisic et al. 2010: 196 (in part).

Type species. Helix vinitincta Cox, 1868 .

Diagnosis. Shell small to very small, brown to dark reddish brown, strongly biconcave with a deeply depressed spire, last whorl greatly inflated. Protoconch sculpture finely cancellate comprising up to 40 very closely spaced, fine spiral lirae intersected by numerous fine radial threads, forming minute beads at their intersections; teleoconch with bold, very crowded to widely spaced sinuate radial ribs; microsculpture cancellate with prominent microradial ribs and low microspiral cords. Umbilicus narrow U-shaped. Penial sculpture of long, simple or anastomosing, longitudinal pilasters (all taxa) with small crowded pilasters above the epiphallic entrance. Verge absent.

Distribution and habitat. Richmond River, north-eastern NSW to Mt Tamborine, south-eastern Queensland; found in lowland to mid-altitude rainforest on volcanics, living on the underside of logs.

Remarks. Gyrocochlea Hedley, 1924 was restricted by Stanisic (1990) to include only G. vinitincta ( Cox, 1868) (type species), G. convoluta Hedley, 1924 , G. paucilamellata Stanisic, 1990 and G. curtisiana ( Hedley, 1912) . G. curtisiana is here excluded from Gyrocochlea on the basis of significant differences in protoconch sculpture (coarsely and broadly cancellate) and general shell morphology (less depressed spire, looser coiling) when compared with these species. The unpublished results of this study, which examined the protoconchs of nautiliform charopids from the entire eastern Australian region, indicate that G. curtisiana belongs to a clade widespread in southern and central Queensland. However, re-assignment to a new genus is delayed pending formal revision of these charopids.

Stanisic et al. (2010) listed 34 species (including 22 newly described) under the Gyrocochlea ‘umbrella’ as a provisional ‘roadmap’ to revisionary studies of these nautiliform charopids. While some of these species have been dealt with in the present publication and re-assigned to new genera, unpublished evidence gained through the current project indicates, that apart from the three core species mentioned above, all remaining species listed in Stanisic et al. (2010) will eventually have to be re-allocated to other genera.