Helix eta Pfeiffer, 1853

Brook, Fred J. & Ablett, Jonathan D., 2019, Type material of land snails (Mollusca: Gastropoda) described from New Zealand by taxonomists in Europe and North America between 1830 and 1934, and the history of research on the New Zealand land snail fauna from 1824 to 1917, Zootaxa 4697 (1), pp. 1-117 : 42-43

Helix eta Pfeiffer, 1853

Pl. 5, fig. A

Pfeiffer, 1853. Monographia heliceorum viventium, 3: 107.

Type material: Lectotype, NHMUK 1962725 (dry shell material); ex Museum Cuming (Acc. no. 1829) . Lectotype fixed by inference of holotype ( ICZN Article 74.6) by Climo (1970a: 315) (dry shell material). Possible paralectotypes (2), ZMH 45987, from Altonaer Museum, coll. O. Semper ex Cuming. We were unable to obtain images of the specimens in ZMH and do not know if they are conspecific with the lectotype .

Label details of lectotype: ‘n.sp. H. eta Pfr. N. Zealand’—in Pfeiffer’s handwriting.

Type locality: ‘Nova Seelandia’ (Pfeiffer 1853: 107, 1854a: 57).

Previous illustrations of type material: Climo (1981: figs. 1A–C). A shell purported to be Helix corniculum [= H. eta , see below] was illustrated by Reeve (1852 [in 1851–1854]: pl. 133, fig. 826) [and reproduced by Tryon

(1887: pl. 3, fig. 12)], but does not match Reeve’s accompanying description, or the type material of corniculum , and evidently represents another species.

Remarks: Helix eta Pfeiffer, 1853 and H. corniculum Reeve, 1852 are based on the same type material, which H. Cuming had obtained from the Australian-based naturalist Frederick Strange. Pfeiffer evidently intended to publish the original description of this species in the Proceedings of the Zoological Society of London issue for 1851 (see Reeve 1852 [in 1851–1854]: species 826; Pfeiffer 1853a: 107), but publication was delayed until 1854 ( Pfeiffer 1854a: 57), and was pre-empted by Reeve (1852 [in 1851–1854]) [note that the publication date of ‘ October 1851 ’ listed for plate 133 of Reeve (1851 –1854) is presumed to be an error, as the immediately preceding and following plates were dated ‘ October 1852 ’ (see Petit 2007: table 3)]. However, as noted under corniculum Reeve , this name is a junior homonym of Helix corniculum Hombron & Jacquinot, 1847 , applied to material from New Guinea ( Martens 1873: 10), and so Helix eta Pfeiffer, 1853 is the earliest available name for the New Zealand species. Historically there was considerable confusion over the identity of Helix corniculum Reeve and Helix eta Pfeiffer , as noted by Climo (1981) and Goulstone (1995). Some authors (including Suter 1913b: 725; Iredale 1915a: 482; Solem 1959: 83; Climo 1970a: 314; Powell 1979: 310; Schileyko 2001: fig. 1291) used Reeve’s or Pfeiffer’s names for species with a spirally-ribbed protoconch and radially ribbed teleoconch. However, Climo (1981) noted that the type material of Helix corniculum Reeve and Helix eta Pfeiffer has a radially-ribbed protoconch, and matches shells that some authors (including Suter 1913b: 715; Iredale 1915a: 482; Powell 1939: 238; Climo 1970a: 330; Powell 1979: 309; Schileyko 2001: fig. 1288) had incorrectly identified as Helix caput-spinulae Reeve, 1852 (see entry for caput-spinulae below). Iredale (1915) erected the genus Mocella for a group of New Zealand charopids with spirally-ribbed protoconchs, and designated Helix corniculum Reeve, 1852 as the type species, based on a misinterpretation of that species. Climo (1981) and most subsequent authors have assigned Helix eta Pfeiffer, 1853 , and morphologically similar taxa with radially-ribbed protoconchs, to Mocella , based on a literal interpretation, rather than the intent, of Iredale’s (1915) generic classification (see ICZN Article 70.3.1). Goulstone (1995: 66) erected the genus Climocella for the group of New Zealand species with spirally-ribbed protoconchs that had previously been included in Mocella . New Hebridean and Solomon Island species that were assigned to Mocella by Solem (1959, 1960) were transferred to Sinployea Solem, 1983 by Solem (1983).

Current Taxonomy: Listed as Mocella eta (Pfeiffer, 1853) by Climo (1981: 9), Spencer & Willan (1995: 40) and Spencer et al. (2009: 215).

Distribution: New Zealand; North Island, northern South Island, Chatham Islands (Suter 1913b—as Endodonta caput-spinulae ; Wallace 1977 —as Charopa caputspinulae ; Powell 1979 —also as C. caputspinulae ).