Limnaea tenella Hutton, 1884

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 : 18-19

Limnaea tenella Hutton, 1884

Pl. 1, fig. L

Hutton, 1884 . New Zealand Journal of Science, 2: 175.

Type material. Syntypes, CMNZ M359 (1), CMNZ M6051 (2), NMNZ M.125546 [ex Suter colln.] (2) (dry shells). The molluscan collection at CMNZ has radula fragments mounted on a glass slide with the label details ‘ Limnaea tenella, Christchurch, XVII p. 55’—in Hutton’s handwriting (i.e., CMNZ 2017.17.149), which are probably primary type material (see description of radula by Hutton 1885c: 56 ).

Label details. CMNZ M359 —‘18. Limnaea tenella Hutton, R. Heathcote , Christchurch’, pillbox label in Hutton’s handwriting ; NMNZ M.125546—‘ Limnaea tenella Hutton , Syntype, Heathcote Riv, Hu. ’, in H. Suter’s handwriting .

Type locality. ‘Christchurch’ ( Hutton 1884h: 175 ); ’River Heathcote, Christchurch’ ( Hutton 1885c: 56 ).

Previous illustrations of type material. Hutton (1885c: pl. xii, figs. 4, 11—shell and radula).

Remarks. Hutton submitted a description of this species to the Transactions and Proceedings of the New Zealand Institute issue for 1884, but publication was delayed until May 1885 ( Hutton 1885c: 55 ), and was pre-empted by a brief description in an account of a meeting of the Philosophical Institute of Canterbury ( Hutton 1884h: 175 ). Hubendick (1951: 171, 179, 200) treated Limnaea pucilla Hutton, 1884 and Limnaea alfredi Suter, 1890 , which was based on shells from Hooker Valley, Canterbury, as synonyms of Limnaea tenella Hutton, 1884 , and noted that the shells of this taxon were similar to those of the European species Galba truncatula (Müller, 1774) , albeit with a less elevated spire. However, according to Dell (1956: 73), L. tenella is based on juvenile shells of Lymnaea stagnalis (Linnaeus, 1758) . Hutton (1882h: 157) had earlier noted that the latter species had been “introduced intentionally into the river Avon at Christchurch, and is now abundant at the Acclimatization Gardens”. According to Thomson (1922: 259), L. stagnalis was originally introduced to the Avon “from England in 1864, by Mr A.M. Johnson of Opawa [Christchurch], who brought them out as food for the fish he was endeavouring to introduce”. Dell (1956: 73) noted that L. stagnalis was “widely distributed in sluggish streams and particularly in lakes throughout New Zealand ”. Pullan et al (1972: 397, figs. 1a, 1b) indicated that it had a sparse distribution in the North and South islands, in lakes, ponds, man-made dams and slow-flowing streams. Lymnaea stagnalis is native to Eurasia, the western part of North Africa, and central and western North America, and has a wide adventive distribution that includes Australia and New Zealand ( Hubendick 1951: 118, fig. 301; Welter-Schultes 2012: 50).

Current taxonomy. A junior synonym of Lymnaea stagnalis (Linnaeus, 1758) , according to Dell (1956: 73).

Infraclass Pulmonata

Order Stylommatophora

Family ATHORACOPHORIDAE P. Fischer, 1883