Helix igniflua Reeve, 1852

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 : 46-47

Helix igniflua Reeve, 1852

Pl. 5, fig. C

Reeve, (1851–1854) 1852. Conchologia iconica, 7: species 774, pl. 128, fig. 774.

Type material: Syntypes, NHMUK 1996111 (2) , NHMUK 1996112 (3) (dry shell material) ; ex Museum Cuming (Acc. no. 1829).

Label details: ‘New Zealand’.

Type locality: ‘New Zealand’ (Reeve 1852 [in 1851–1854]: species 774).

Previous illustrations of type material: Reeve (1852 [in 1851–1854]: pl. 128, fig. 774); Tryon (1885 [from Reeve, 1852]: pl. 26, fig. 25).

Remarks: Helix igniflua Reeve, 1852 and H. lambda Pfeiffer, 1853 are based on the same type material. Pfeiffer evidently intended to publish the original description of this species in Proceedings of the Zoological Society, 1851 (see Reeve 1852 [in 1851–1854]: species 774; Pfeiffer 1853a: 85), but publication was delayed until 1854 ( Pfeiffer 1854a: 57), and was pre-empted by Reeve (1852 [in 1851–1854]). Examination of type material indicates that H. igniflua is conspecific with H. obnubila Reeve, 1852 (see entry for obnubila below). The original illustrations and accompanying descriptions of both these species were apparently published simultaneously, in a part of Reeve’s Conchologia iconica that was listed as having been issued in October 1852. The type lots of H. igniflua contain intact and damaged shells of fully-grown individuals, all of which lack a periostracum, whereas the type material of H. obnubila [= NHMUK 20041001] comprises a single juvenile shell with a thick, dark-brown periostracum. The taxa represented by these type lots have had a complicated nomenclatural history. Helix igniflua [= H. lambda ] and H. obnubila have been treated as separate species (e.g., Martens 1873; Hector 1873; Hutton 1880; Tryon 1885; Pilsbry 1892 [in 1892–1893], 1893 [in 1893–1895]; Powell 1937, 1946 b, 1957, 1962), and obnubila has been listed as a subspecies or variety of igniflua (e.g., Hedley & Suter 1893: 636; Suter 1902b: 208, 1904a: 64, 1913b: 629). Other workers have recognised a single species only. Hutton (1884b: 203) listed H. igniflua , H. lambda & H. sigma Pfeiffer (= nomen nudum) as junior synonyms of H. obnubila . Suter (1894a: 127) noted “that they are all one and the same species, and that there is not even a possibility of making out a constant variety……The differences in the shell seem to be due to the influence of habitat only. The dentition is the same in both”. Helix obnubila and H. lambda were listed as junior synonyms of H. igniflua by Suter (1894b: 147, 1894d: 256) and Powell (1976: 117, 1979: 317), and this interpretation has been followed in recent systematic lists (i.e., Spencer & Willan 1995; Spencer et al. 2009). However, if H. igniflua and H. obnubila are in fact conspecific, then Hutton’s synonymy takes precedence, under the Principal of the First Reviser (ICZN Article 24.2). Following Pilsbry (1892 [in 1892–1893: 72) this taxon has generally been assigned to Thalassohelix Pilsbry, 1892 , at genus or subgenus level, but preliminary results of a phylogenetic study (M. Kennedy & F. Brook unpub. data) indicate that this placement requires re-evaluation.

Taxonomy: Treated as a junior synonym of Helix obnubila Reeve, 1852 by Hutton (1884b: 203).