Plectopylis karenorum (W. Blanford, 1865 )

Páll-Gergely, Barna, 2018, Systematic revision of the Plectopylinae (Gastropoda, Pulmonata, Plectopylidae), European Journal of Taxonomy 455, pp. 1-114 : 94-95

Plectopylis karenorum (W. Blanford, 1865)

Figs 35J, 41E

Helix (Plectopylis) karenorum Blanford, 1865: 73–75 , 94. [“Banks of Tsanda Khyoung, near Kaintha village, in Henzada district, Pegu ”, “on the banks of the Nungatho Khyoung, Henzada district”].

Helix karenorum – Pfeiffer 1868: 397; 1869: 503, pl. 108, figs 16–18.

Helix (Plectopylis) karenorum – Hanley & Theobald 1870: 7, pl. 13, fig. 6. — Godwin-Austen 1875b: 613, pl. 74, fig. 5a. — Nevill 1878: 72. — Tryon 1887: 164, pl. 35, figs 96–100.

Plectopylis karenorum – Gude 1897b: 244–245, fig. 35a–d.

Plectopylis (Plectopylis) karenorum – Gude 1899d: 148; 1899e: 175; 1914b: 132–134, fig. 66a–d.

Diagnosis

A small to medium-sized, fragile species having lighter and darker stripes on the dorsal side; the angled body whorl and concomitantly entirely flat dorsal surface is characteristic for this species.

Type material

No specimens of Plectopylis karenorum were found in the type collection of the NHM. However, I found samples collected by Blanford and labelled as being collected from one of the type localities. Therefore, the samples detailed below probably represent syntypes.

Material examined

Syntypes

MYANMAR: 2 shells, Pegu, Nungathokhyoung, Henzadah, coll. Blanford ( NHMUK 1906.2.2.263); 5 shells, Pegu, Henzadah, coll. Blanford ( NHMUK 1906.2.2.146).

Additional material

MYANMAR: 1 shell, Pegu, coll. Möllendorff ( SMF 150097); 7 shells, Herizadah ( NHMUK); 1 shell, Burmah, Pegu, coll. A. S. Kennard ( NHMUK); 1 shell, Moulmain?, coll. Godwin-Austen ( NHMUK 1903.7.1.735); 3 shells, Burma, Pegu, ex coll. Museum Cuming ( NHMUK); 3 shells, Burmah, coll. Godwin-Austen ( NHMUK 1903.7.1.737); 3 shells, Henzada District ( NHMUK 1888.12.04.1548– 1550); 1 shell, Pegu, ex coll. H. Adams ( NHMUK 1878.1.28.283).

LOCALITY UNKNOWN: 2 juv. shells, no data, coll. H.F./W.T. Blanford, acc. 1944 ( NHMUK).

Description

SHELL. Sinistral, completely flat, unusually thin-walled for Plectopylis ; colour basically greyish with brownish-corneous stripes; protoconch consists of 2.75–3 whorls, extremely finely tuberculated and roughly, irregularly wrinkled; whorls 5.5–6, separated by relatively shallow suture; whorls strongly angled, which results in an entirely flat dorsal surface; whole shell with fine reticulated sculpture; dorsal side and area inside umbilicus dominated by spiral lines (or spiral and radial lines are of comparable strength); periphery of body whorl dominated by radial wrinkles; aperture small, rather rounded, peristome slightly thickened and reflected; parietal callus strongly developed but blunt, slightly S-shaped, upper part of ‘S’ shorter; apertural fold in contact with parietal callus.

Three opened shells were examined. Lambda-complex complete; left leg with a posteriorly elongated end; upper branch approximately as long as elongated part of left leg; right leg with anteriorly and somewhat obliquely elongated end; main plica in contact with right leg. Palatal plicae typical of Plectopylis .

MEASUREMENTS (in mm). D = 12–14.1, H = 3.9–5.1 (NHMUK 1906.2.2.146, n = 4); D = 18.4–19.7, H = 5.6–5.9 (NHMUK 1906.2.2.263, n = 2).

Differential diagnosis

Plectopylis karenorum can be distinguished from all congeners by the flat, solid, thin-walled shell with shouldered body whorl and striped colouration.

Distribution

This species has been reported from several Burmese localities.