Chersaecia shiroiensis shiroiensis (Godwin-Austen, 1875)

Páll-Gergely, Barna, 2018, Systematic revision of the Plectopylinae (Gastropoda, Pulmonata, Plectopylidae), European Journal of Taxonomy 455, pp. 1-114 : 65-66

Chersaecia shiroiensis shiroiensis (Godwin-Austen, 1875)

Figs 24I–J, 30A

Helix (Plectopylis) shiroiensis Godwin-Austen, 1875b: 609 , 613, pl. 73, fig. 3–3c [“slopes of the peak of Shiroifurar, N.E. of Munipúr, at an altitude of from 8000 to 9000 feet ”].

Helix (Plectopylis) shiroiensis – Hanley & Theobald 1876: 64, pl. 159, fig. 7. — Nevill 1878: 70. — Tryon 1887: 163, pl. 35, fig. 90.

Plectopylis shiroiensis – Gude 1896a: 155–156, fig. 20a–d.

Plectopylis (Chersaecia) shiroiensis – Gude 1899d: 148; 1899e: 175; 1914b: 105–106, fig. 49a–d.

Chersaecia shiroiensis – Páll-Gergely et al. 2015c: 10.

Diagnosis

Intermediate and lower plicae present.

Material examined

Syntypes

INDIA: 10 shells, Naga Hills, Shiroifurar ( NHMUK 1903.7.1.747).

Additional material

INDIA: 2 shells, Naga Hills, Japvo Pk, 10 000 ft a.s.l., coll. Godwin-Austen ( NHMUK 1903.7.1.748); 1 shell, Naga Hills, Kopamedza Pk, coll. Godwin-Austen ( NHMUK 1903.7.1.775); 1 shell, Burrail, Japvo Pk., coll. Godwin-Austen ( NHMUK); 1 shell, Naga Hills, Ogle leg., coll. Godwin-Austen ( NHMUK 1903.7.1.232); many shells, Shiroifurar, NE Manipur, Assam, coll. Godwin-Austen ( NHMUK); 1 shell, Munipur, 1875, Nevill leg. ( NHMUK 1891.3.17.350–351); 3 shells, India ( NHMUK 1909.1.26.74[?]); 2 adult shells, 1 juv. shell, Gazifhima, Lahupa, Naga Hills, Godwin-Austen leg. ( NHMUK 1903.7.1.778).

Description

SHELL. Sinistral, light brownish or yellowish, small, spire slightly elevated; protoconch consists of 2.25 whorls, separated by shallow suture, finely, rather regularly wrinkled with extremely fine granular structure; entire shell with 5.5–6 whorls (n = 4); suture of teleoconch deep; teleoconch finely reticulated, radial lines usually dominant, but on dorsal side of last whorl spiral lines stronger; ventral surface also reticulated; aperture semilunar; peristome white, conspicuously thickened and strongly reflected; parietal callus V-shaped with the upper part of V being shorter; apertural fold prominent, continuous with main plica; periumbilical region slightly keeled, last half whorl slightly angulated and dorsolaterally depressed; last half whorl flares away from umbilicus; this modifies the regular infundibular shape of umbilicus (behind aperture, inside the last half whorl there is a slight canal).

Five shells were opened. Parietal wall with a vertical lamella, which has the upper end slightly, and the lower end more strongly elongated posteriorly; main plica free from lamella, in contact with apertural fold; main plica slightly curved, its middle portion situated closer to upper suture than its two ends; lower plica starts under lamella, slightly shorter than lamella; intermediate plica approximately as long as lamella, free from it. Palatal plicae six; first and second straight, third slightly oblique; fourth and fifth almost vertical; last one extremely long and rather straight, runs along periumbilical keel; there is an additional free denticle posteriorly.

MEASUREMENTS (in mm). D = 8–8.3, H = 4.4–4.5 (NHMUK 1903.7.1.778, n = 2).

Differential diagnosis

See under Chersaecia shiroiensis subnagaensis subsp. nov.

Distribution

The nominotypical subspecies is known from a few localities from the Naga Hills of India.