Nanina tullia Gray, 1850

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 : 60-61

Nanina tullia Gray, 1850

Pl. 14, fig. G

Gray, 1850. Proceedings of the Zoological Society of London, 17 (1849): 165.

Type material: Syntypes (3), NHMUK 1849.12.3.80–83 (dry shell material), according to Climo (1969c: 5, 6); types not found in NHMUK collections in 2018, whereabouts unknown.

Type locality: ‘ Auckland, New Zealand’ (Gray 1850: 165) .

Previous illustrations of type material: Reeve (1854 [in 1851–1854]: pl. 207: fig. 1460)—probable syntype; Tryon (1886 [from Reeve 1854]: pl. 62, fig. 40)—probable syntype.

Remarks: There has been considerable confusion over the identity of Nanina tullia among New Zealand authors, with the name generally having been applied to various species of Allodiscus Pilsbry, 1892 (e.g., Suter 1913b;

Powell 1979; Marshall & Barker 2008). The original description, which was reproduced by Gray (1851: 65), was based on specimens collected at or near Auckland by Joseph Greenwood (Gray 1850: 164, 165). The type material was part of a large collection of marine, terrestrial and fresh-water molluscs from New Zealand that was sent to the British Museum by Greenwood in the late 1840s (see Introduction). Reeve (1854 [in 1851–1854]: pl. 207, fig. 1460) illustrated a specimen from the British Museum that was probably part of the type series of Nanina tullia (here reproduced in pl. 14, fig. G). We were not able to find the type material in the NHMUK collection, but Climo (1969c: 5, 6) had previously noted that “Examination of one of Gray’s syntypes (Reg. No. 49. 12. 3. 80 —83), from the British Museum (Nat. Hist.), has revealed that tullia is synonymous with Charopa (Ptychodon) pseudoleioda ( Suter, 1890) . …. That such a gross misuse of a name could occur is probably the result of the inadequate nature of the original diagnosis which does not mention the most characteristic feature of the species, the lamellate aperture. The shell dimensions given by Gray [i.e., ‘Diam. 1 / 9 of an inch’ = 2.8 mm], and the shell coloration, agree with those of pseudoleioda .” Marshall & Barker (2008: 91), in a revision of Allodiscus Pilsbry, 1892 , mentioned Climo’s observations on the type material of tullia , but designated a specimen in NHMUK 1849.12.22.128 (pl. 7, fig. D), from a collection sent to the British Museum in 1849 by Captain Stokes of H.M.S. Acheron (see Introduction), as the lectotype of Nanina tullia Gray. They noted that the species represented by this specimen was restricted to the northeastern and central South Island, inferred that Gray’s Auckland locality record was an error, and designated the type locality as Fyffe Palmer Reserve, Kaikoura, in the South Island. However, the available evidence clearly indicates that Nanina tullia Gray and Allodiscus tullia sensu Marshall & Barker are distinct species that differ morphologically and in distribution, and that NHMUK 1849.12.22.128 is not from the type series of Gray’s species. We accept Climo’s interpretation that Helix (Huttonella) pseudoleioda Suter, 1890 , which was described from Forty Mile Bush in the southern North Island, is conspecific with Nanina tullia Gray, 1850 , but for nomenclatural stability, and to avoid confusion, pseudoleioda is preserved here as the valid name (i.e., nomen protectum) for this taxon in accordance with ICZN Article 23.9.2, with tullia as a nomen oblitum. Although Gray’s name is the earliest available for this species, it has not been used as a valid name since 1899 (ICZN Article 23.9.1.1), whereas pseudoleioda has been used consistently as a presumed valid name since 1890. The latter name has been mentioned ‘in at least 25 works, published by at least 10 authors in the immediately preceding 50 years [i.e., since 1969] and encompassing a span of not less than 10 years’ (see synonymy in Appendix 1), as required under ICZN Art. 23.9.1.2 for reversal of precedence of nomenclatural priority. Endodonta (Ptychodon) ureweraensis Suter, 1899 is a junior synonym ( Climo, 1969a: 198). The South Island charopid species referred to as tullia by Marshall & Barker (2008) is unnamed and requires formal description.

Taxonomy: Nanina tullia Gray, 1850 is treated here as a junior synonym of Helix (Huttonella) pseudoleioda Suter, 1890 nomen protectum. The latter species has been assigned to Huonodon Iredale, 1945 by Climo (1981: 14) and most subsequent authors, but preliminary results of a phylogenetic study (M. Kennedy, T. King & F. Brook unpub. data) indicate that this placement requires re-evaluation.