Leptopoma calva Hutton, 1882

Brook, Fred J., Kennedy, Martyn, King, Tania M., Ridden, Johnathon, Shaw, Matthew D. & Spencer, Hamish G., 2020, Catalogue of New Zealand land, freshwater and estuarine molluscan taxa named by Frederick Wollaston Hutton between 1879 and 1904, Zootaxa 4865 (1), pp. 1-73 : 12-13

Leptopoma calva Hutton, 1882

Pl. 1, fig. C

Hutton, 1882. New Zealand Journal of Science, 1: 282.

Type material. Single shell formerly in the collection at Canterbury Museum, Christchurch ( Hutton 1898 – 1900: 5; Suter 1913: 179) but reported missing by Freeman et al. (1997: 36), and not found subsequently. Neotype selected by Marshall & Barker (2007: 60 — NMNZ M.174790).

Type locality. listed as ‘Greymouth (R. Helms)’ by Hutton (1882p: 282, 1883d: 140); neotype from ‘South Island, N of Arthur’s Pass, Jacksons, near roadside on Otira–Kumara highway, 200 m (NZMS 260, K33/870283)’ ( Marshall & Barker 2007: 60).

Previous illustrations of type material. Suter (1915: pl. 35, fig. 1), Marshall & Barker (2007: fig. 4C).

Remarks. Hutton submitted a description of this species to the Transactions and Proceedings of the New Zealand Institute issue for 1882, but publication was delayed until May 1883 ( Hutton 1883d: 140), and was preempted by a brief description in an account of a meeting of the Philosophical Institute of Canterbury ( Hutton 1882p: 282). A re-description and illustration of Leptopoma calva by Suter (1913: 179, pl. 35, fig. 1) was based on the type material from Canterbury Museum. Suter (1913: 179) and Dell (1955: 1136) stated that this species was known from the type specimen only. The latter author noted that Suter’s (1913) “description and figure are not highly diagnostic. Unfortunately the type cannot at present be located in the Canterbury Museum, and no topotypes appear to have been collected”. Dell (1955: 1136) identified material of “a moderately common shell in Fiordland” as Murdochia cf. calvum (Hutton), but noted that “until these shells can be critically compared with undoubted specimens of calvum, the identification cannot be certain”. Marshall & Baker (2007) redescribed Leptopoma calva Hutton, 1882 as part of a taxonomic review of Cytora Kobelt & Möllendorff, 1897 , noting that the shell of this species is distinctive in having a maculate colour pattern, although the latter feature was not mentioned in the descriptions by Hutton (1882p, 1883d) or Suter (1913), and they identified ‘ Murdochia cf. calvum ’ of Dell (1955) as Cytora mayhillae Marshall & Barker, 2007 . Marshall & Barker (2007: 60) selected a neotype of calva, NMNZ M. 174790 (pl. 1, fig. C), that “represents the only Cytora species occurring in the vicinity of Greymouth that is accordant with Hutton’s descriptions and Suter’s (1913) crude illustration of the holotype ”. This in itself is not sufficient justification for the designation of a neotype under ICZN Art. 75.3 but, given that previously there had been confusion over the identity of calva , we agree that a neotype was required to stabilise the nomenclature. The neotype selected by Marshall & Barker (2007: 60) was from the Otira-Kumara Highway, c. 45 km SE of Greymouth; they stated that they had “not seen any reliably localised specimens from Greymouth or the immediate vicinity of that town, so we have chosen the neotype from one of the nearest localities where the species is definitely known to occur”. Subsequently, C. calva has been found living in Omotumotu Bush, Greymouth, and on Peter Ridge, and near Point Elizabeth, on the southern and northern outskirts of the town, respectively (F. Brook pers. obs.).

Current taxonomy. Cytora calva (Hutton, 1882) — Powell (1957: 90), Powell (1979: 85), Marshall (1995: 496), Marshall & Barker (2007: 60), Spencer et al., (2009: 203).

Distribution. New Zealand; northwestern South Island, from Granity and Nelson Lakes southwest to Lake Kaniere ( Marshall & Barker, 2007: fig. 8A; NMNZ collection records).