Rissoa vana Hutton, 1873

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 : 15

Rissoa vana Hutton, 1873

Pl. 1, fig. G

Hutton, 1873 . Catalogue of the Tertiary Mollusca and Echinodermata of New Zealand: 12.

Type material. Lectotype, NMNZ M.1760 (dry shell) . Lectotype fixed by inference of holotype ( ICZN Art. 74.6) by Marshall (1996: 20) .

Label details. ‘ Rissoa vana (Hutton) , Awamoa, Holotype’, in R.K. Dell’s handwriting.

Type locality. ‘Awamoa’ ( Hutton 1873c: 12 ).

Remarks. Primary type material of Rissoa vana Hutton is illustrated here for the first time in pl. 1, fig. G. The original description of this species was based on one or more specimens collected from Awamoa Creek, Oamaru. Hutton (1873c) interpreted vana as a marine species derived from a Miocene fossil assemblage, but Finlay (1924: 491, 493) pointed out that it is a synonym of the extant freshwater snail Amnicola badia Gould, 1848 [= Potamopyrgus antipodarum (Gray, 1843) ]. Finlay (1924) noted that this species was common in Awamoa Creek and suggested that the type material of vana was probably collected from Recent flood deposits. Potamopyrgus antipodarum is widely distributed throughout New Zealand in fresh and brackish water ( Winterbourn 1970, Haase 2008: 103). It also has a wide adventive distribution in southeastern Australia and Tasmania ( Ponder 1988) and Europe (e.g., Welter-Schultes 2012: 40), and is adventive also in North America (e.g., Richards et al. 2001, Alonso & Castro-Diez 2008) and Japan (Shimada & Urabe 2003).

Current taxonomy. A subjective junior synonym of Potamopygus antipodarum (Gray, 1843) — Finlay (1924: 491, 493), Marshall (1996: 20).

Subclass Heterobranchia

Order Hygrophila