Chilonopsis blofeldi ( Forbes, 1852 )

Gerlach, Justin, Griffiths, Owen, Hume, Julian P., Louchart, Antoine, Sorrel, Philippe & Cairns-Wicks, Rebecca, 2025, Diversity of the extinct land snail genus Chilonopsis of St Helena (Mollusca: Gastropoda: Achatinidae), European Journal of Taxonomy 1007, pp. 176-210 : 194-196

Chilonopsis blofeldi ( Forbes, 1852)

Figs 4c , 9a–c

Bulimus Blofeldi Forbes, 1852: 4 , pl. 5 fig. 2.

Bulimulus blofeldi – Melliss 1875: 122. — Wollaston 1878: 546. — Smith 1892: 265. Helenopachnodus Blofeldi – Germain 1931: 169 .

Chilonopsis blofeldi – Crowley & Pain 1977: 561.

Type material

Not located, collected by J.H. Blofeld, “in a reddish clay or loam on the side of a hill overlooking the “Briars” in the cutting of the road from James Town to Longwood, about 1200 feet above the sea-level” ( Blofeld 1852).

Other material examined

SAINT HELENA • 1 shell; Captain Geoge Grey leg.; NHMUK 1841.4.19.734 • 1 shell; 1840; Dr J. Hooker leg.; NHMUK 1868.12.26.1 • 1 shell; J.C. Melliss leg.; NHMUK 1873.11.19.43 • 1 shell; W.H. Turton leg.; NHMUK 1892.2.24.219-223 • 1 shell; Tomlin collection; NMW. 1955.158.27974 • 2 shells; sidepath road, above the Briars; 1200 ft; W.H. Turton leg.; Pain collection; NMW. 1981.118 • 7 shells; W.H. Turton leg.; USNM 126263 .

Diagnosis

A uniquely evenly ovate Chilonopsis with a broadly expanded body whorl; columella simple but distinctly curved on the left margin.

Description

A large species (height 25.9–30.2 mm; Table 1 ). Ovate conical. Thin. Apex acute. 5–6 convex whorls, body whorl ovate, widest at mid-point from apex to base of aperture. Sutures deep, slightly impressed. Protoconch of 1.5–2 whorls, with at least one indistinct spiral stria (all specimens are worn so probably more striae were present). Teleoconch with fine transverse striae, one faint spiral stria visible on the first whorl (probably more were present). Aperture ovate, angled below. Lip very narrowly expanded at base. Margins joined by a palatal callus of variable thickness. Columella vertical; left margin curved, not obscuring umbilicus ( Fig. 9c ). Umbilicus open, narrow.

All specimens are bleached and worn, lacking any trace of original colour and details of sculpture are eroded.

Distribution

Known only from Side Path ( Fig. 11 ). Very common according to Turton (in Smith 1892). Probably extinct by 1852 as Blofeld recorded only buried shells. All specimens seen are bleached subfossils.

Figures

Fig. 4. Species of Chilonopsis. a. C. aurisvulpina (Holten, 1802) (NHMD-172594). b. C. helena (Quoy & Gaimard, 1832) (NHMUK 20240185). c. C. blofeldi (Forbes, 1852) (NHMUK). d. C. lanceoloideus sp. nov., holotype (NHMUK 20240171). e. C. exulatus (Reeve, 1849) (UMZC I.105095). f. C. subtruncatus (E.A. Smith, 1892) (NHMUK 92.2.24.224-8). g. C. turtoni (E.A. Smith, 1892) (NHMUK 1892.2.24.209-218). h. C. subplicatus (G.B. Sowerby I, 1844) (MSH). i. C. melanioides (Wollaston, 1878) (ANSP 97326). Scale bar = 25 mm.

Fig. 9. a–c. Chilonopsis blofeldi (Forbes, 1852). d–f. C. lanceoloideus sp. nov. a. Bulimus Blofeldi Forbes, 1852 figure (Forbes 1852). b. Specimen NHMUK un-numbered (ex Melliss). c. Aperture. d, f. Holotype (NHMUK 20240171). e. Paratype NHMUK 20240172. f. Aperture. Scale bar = 25 mm.

Fig. 11. Distributions of species of Chilonopsis Fischer von Waldheim, 1848.