Helix (Theba) ziczac Gould, 1846

Pl. 14, fig. K

Gould, 1846. Proceedings of the Boston Society of Natural History, 2: 166.

Type material: One or more specimens, consisting of, or including, a syntype at the United Sates National Museum, Washington, DC (see Suter 1894e: 124). Type material details not listed by Johnson (1964: 170 —as H. (T.) zizac sic), and present whereabouts not known. A specimen from ‘Hunua Range, Auckland’, which Henry Suter sent to William Dall to compare with the type material of H. ziczac (see Suter 1894e: 124), has been incorrectly listed in the USNM catalogue as the holotype (i.e., USNM 106958).

Type locality: ‘New Zealand’ (Gould 1846: 166); ‘found by Dr. Pickering, in a crater near Taiaimi, New Zealand’ (Gould 1852: 42).

Previous illustrations of type material: Gould (1856: pl. 3, fig. 44, a–c [reproduced here in pl. 14, fig. K]); Tryon (1886 [from Gould 1856]: pl. 62, figs. 35–37).

Remarks: The place name Taiaimi does not appear on current maps, but comments by Wilkes (1845, vol. 2: 394) indicate that it was located west of the Bay of Islands and had a hot spring that was “situated in a small basin, and forms a lake of three or four acres in extent; near the edge of this lake, gas is constantly bubbling up”. This corresponds to the geothermal area at Ngawha Springs. Wilkes (1845, vol 2: 394) also described the nearby scoria cone of ‘Poerua’ (= Pouerua), and this may be where the type material was collected. Helix portia Gray, 1850 is a subjective junior synonym of H. ziczac Gould (e.g., Hedley & Suter 1893: 635; Suter 1894d: 256, 1894e: 124, 1913b: 632; Powell 1979: 318). Previously Helix collyrula Reeve, 1852 and H. kappa Pfeiffer, 1853 were also treated as junior synonyms of H. ziczac Gould (e.g., Hutton 1884b: 203; Tryon 1886: 213; Hedley & Suter, 1893: 635; Suter 1913b: 632; Powell 1979: 318) but, as noted above, collyrula and kappa, based on the same type material as one another, are a different species. The species name ziczac has been misspelt ‘ ziczag ’ by some authors (e.g., Suter 1913b: 632; Powell 1979: 318; Goulstone 2001: 77; Spencer et al. 2009: 216). Included in Thalassohelix by Pilsbry (1892 [in 1892–1893]: 72; 1893 [in 1893–1895]: 13), Hedley & Suter (1893: 635), Suter (1894e: 123; 1913b: 632), Powell (1979: 318), and transferred to Phenacohelix Suter, 1892 by Goulstone (2001: 77). Protoconch morphology and preliminary results of a phylogenetic study (M. Kennedy, T. King & F. Brook unpub. data) indicate that ziczac is not congeneric with Phenacohelix pilula (Reeve, 1852), the type species of that genus (Pilsbry 1892a: 56), and it is here provisionally assigned to Neophenacohelix Cumber, 1961, pending further study.

Taxonomy: Treated here as? Neophenacohelix ziczac (Gould, 1846) n. comb.

Distribution: New Zealand; northern North IsIand (Goulstone 2001). Records from New South Wales, Australia (e.g., by Gould (1862: 18) and Cox (1868a: 19, 1868b: 71) were in error (see Suter 1894e: 124).