Helix guttula 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 : 93

Helix guttula Pfeiffer, 1853

Pl. 11, fig. C

Pfeiffer, 1853. Zeitschrift für Malakozoologie, 10: 53.

Type material: Syntypes (2), NHMUK 20160063 (dry shell material); ex Museum Cuming (Acc. no. 1829) .

Label details: ‘ guttula Pfr. New Zealand, M.C.’.

Type locality: Vanuatu. Incorrectly stated as ‘ Nova Seelandia’ by Pfeiffer (1853c: 53) .

Previous illustrations of type material: A shell illustrated by Reeve (1853 [in 1851–1854]: pl. 158, fig. 1040), and reproduced by Tryon (1886: pl. 62, fig. 38), may be from the type series, but does not appear to be conspecific with either of the two syntypes in the NHMUK collection (below).

Remarks: The material in the Cuming collection was mis-localised, and there have been no valid records of Helix guttula from New Zealand (see Suter 1892c: 281, 1913b: 684). Recorded from the New Hebrides (= Vanuatu) by Sykes (1902: 196) and Solem (1959: 98). There has been confusion over the identity of Helix guttula . Pfeiffer’s original description was published in March 1853, according to a footnote on p. 64 of volume 10 of Zeitschrift für Malakozoologie. A description and illustration of Helix guttula by Reeve (1853 [in 1851–1854]: pl. 158, fig. 1040), published in May 1853, depicts a relatively high-spired shell that matches neither of the syntypes in NHMUK 20160063, and was evidently based on a different species. Despite this discrepancy, Pfeiffer (1859: 15) listed Reeve’s (1853) figure in synonymy with H. guttula . Sykes (1902: 196) listed Hyalina (Conulus) layardi Thomson, 1885 , from the New Hebrides [ Vanuatu], as a junior synonym of Helix guttula , but Ancey (1905: 42) thought that they were separate species. Baker (1938: 85) referred to specimen lot ANSP 63136, obtained from J. Ponsonby, in 1892, with the following note: “This is, ex typo, H. guttula Pfr. The original specimens are from the New Hebrides [ Vanuatu], not from New Zealand, tho always quoted from the latter locality. My specimens are from Tonga Is. & apparently = excrescens Mss [i.e., Lamprocystis excrescens ( Mousson, 1870) ]. I don’t know the N. Z. shell.” Baker (1938: 85) noted that H. guttula is not definitely recogniseable from Pfeiffer’s description, and that the shell illustrated by Reeve (1853) is not conspecific with L. excrescens (Mousson) . He listed Hyalina layardi as a junior synonym of L. excrescens . Solem (1959: 98, 99) considered Helix guttula to be a New Hebridean species, and listed Hyalina layardi as a junior synonym. He accepted Reeve’s (1853) illustration as accurately representing guttula , although the specimens that Solem listed and illustrated as belonging to this species all have a considerably less-elevated spire. Solem (1959: 99) noted that Helix guttula differs from N. excrescens in “lacking basal teeth in young shells, in having a shorter columellar lamella, and in being much more trochoidal”. The two syntypes of Helix guttula in NHMUK 20160063 differ from one another in relative spire elevation but appear to be conspecific. The larger specimen is illustrated in pl. 11, fig. C. These specimens of H. guttula match syntypes of Hyalina (Conulus) layardi Thomson in the Field Museum of Natural History, Chicago, and the Museum of Zoology, University of Michigan, which were listed and illustrated by Solem (1959: 98, pl. 34, figs. 11, 12) [i.e., FMNH 43041, UMMZ 147868—as ‘paratypes’]. Lamprocystis excrescens and L. ensifera (Mousson) sensu Baker (1938) differ from guttula in having a longer, tongue-like, columellar lamella, and juvenile shells have basal and palatal lamellae, which are lacking in guttula .

Current Taxonomy: Listed as Lamprocystis guttula (Pfeiffer, 1853) by Solem (1959: 98).

Distribution: Vanuatu [ New Hebrides] ( Sykes 1902: 196; Solem 1959: 98).