Plectopylis linterae Möllendorff, 1897

Páll-Gergely, Barna, 2018, Systematic revision of the Plectopylinae (Gastropoda, Pulmonata, Plectopylidae), European Journal of Taxonomy 455, pp. 1-114 : 95-97

Plectopylis linterae Möllendorff, 1897

Figs 35K , 43

Plectopylis linterae Möllendorff, 1897: 28–29 [“ Pegu ”].

Plectopylis linterae var. fusca Gude, 1898g: 170–171 , fig. 89a–f. Syn. nov.

Plectopylis linterae – Gude 1898g: 170, fig. 88a–c.

Plectopylis (Plectopylis) linterae – Gude 1914b: 134–136, fig. 67a–c; 1899d: 148; 1899e: 175. Plectopylis (Plectopylis) linterae var. fusca – Gude 1914b: 136, fig. 68a–f; 1899d: 148; 1899e: 175.

Diagnosis

SHELL. Small, sinistral, thick with slightly elevated spire, strongly thickened peristome, and a main plica, which is weak, and sometimes free from the apertural fold.

Material examined

Types MYANMAR: 1 shell, probably holotype (labelled as lectotype) of P. linterae (D = 15.7 mm), Pegu, coll. Möllendorff ( SMF 9280).

The type sample of P. linterae var. fusca Gude, 1898 could not be located in the NHM.

Additional material

MYANMAR: 2 shells, Pegu, coll. Bosch, ex Rolle ( SMF 172062); 3 shells (labelled as “var. fusca ”), Pathung-Thoung, Attaram R. ( NHMUK 1888.12.4.1541–1543); 1 shell, Burma ( NHMUK 1916.3.16.5); 2 shells (labelled as “ pachystoma ”), Burmah, Theobald leg. ( NHMUK 1903.07.01.736); 1 opened shell (labelled as “ karenorum ”), Moulmain(?), coll. Godwin-Austen ( NHMUK 1903.07.01.735); 1 shell (labelled as “ pachystoma ”), Molmein ( NHMUK 1906.01.01.741); 5 shells (photos of one shell examined, see Fig. 43A ), India, coll. Linter ( RAME 1720/1909/D7.48a-e).

Description

SHELL. Sinistral, strongly built, spire somewhat elevated, dorsal surface slightly conical, shell outline slightly oval; colour dark yellowish-greyish to brownish and reddish; protoconch consists of 2.5– 2.75 whorls, matt, very finely, irregularly wrinkled with extremely fine granular structure; whole shell dominated by irregular, fine wrinkles; dorsal side and area inside umbilicus finely reticulated; periumbilical area smooth, although rather roughly wrinkled near aperture; whorls 5.25–5.75 (n = 4), body whorl rounded; aperture rounded or oval; peristome strongly thickened and slightly reflected; parietal callus elevated, strong, S-shaped; apertural fold strong, free from the parietal callus or slightly connected to it; umbilicus funnel-shaped, relatively narrow, with a blunt periumbilical keel.

One opened shell was examined. Lambda-complex complete; both legs with slightly elongated ends anteriorly and posteriorly; upper branch as long as extension of left leg; main plica in contact with right leg, free from apertural fold or connected to it; main plica always much weaker than apertural fold. Palatal plicae typical to Plectopylis .

MEASUREMENTS (in mm). D = 15.7–16.2, H = 5.6–6.6 (lectotype and paralectotypes, n = 3); D = 16–16.9, H = 5.4–5.5 ( “var. fusca ”, NHMUK 1888.12.4.1541–43, n = 3).

Differential diagnosis

In shell shape Plectopylis linterae is most similar to P. crassilabris sp. nov., which is larger, lacks the main plica and has a stronger spiral sculpture. Typical specimens of P. linterae are much smaller than P. bensoni , have a more elevated spire and a more rounded body whorl. Although in some (probably very old) specimens of P. linterae the apertural fold is connected to the main plica, the apertural fold is always much stronger (more elevated) than the main plica. The apertural fold and the main plica are always connected in P. bensoni , and their boundary is not visible.

Distribution

Plectopylis linterae is known from Pegu only. The exact geographic position of the other locality (Pathung-Thoung) is unknown.

Remarks

The species is sometimes named as “ Plectopylis pachystoma Theobald ” on museum labels, but this name has never been published. Although the types of Plectopylis linterae var. fusca could not be found in the NHM, I found non-type shells labelled “var. fusca ”. Those specimens differ from typical P. linterae in the uniformly brown dorsal surface, which is not sufficient for distinction on any taxonomic levels, meaning Plectopylis linterae var. fusca is a synonym of P. linterae .

Figures

Fig. 35. Parietal (A–E, G, I–L, N) and palatal (F, H, M, O) plication of species of Plectopylis Benson, 1860. A. P. anguina Gould, 1847, paralectotype (NHMUK 20140812). B. P. repercussa Gould, 1856, lectotype (MCZ 169336). C. P. bensoni var. repercussoides Gude, 1899, holotype (NHMUK 1922.8.29.46). D. P. cairnsi Gude, 1898, holotype (NHMUK 1922.8.29.47). E–F. P. cairnsi (UF 76761). G–H. P. crassilabris sp. nov., paratype (UF 448577). I. P. cyclaspis Benson, 1859 (NHMUK 1906.02.02.148). J. P. karenorum (W. Blanford, 1865) from “Pegu”, Myanmar (NHMUK). K. P. linterae var. fusca Gude, 1898 (NHMUK 1888.12.04.1541–3). L–M. P. malayana sp. nov., paratypes from the type locality (coll PGB). N–O. P. thompsoni sp. nov., paratype (UF 448578). Arrows below the letters indicate the direction of the aperture. Not to scale.

Fig. 43. Photos of Plectopylis linterae Möllendorff, 1897. A. Shell from Myanmar (RAME 1720/1909/ D7.48a). B–D. Holotype (SMF 9280). Scale bars: D (protoconch) = 2 mm; A–B (shells) = 10 mm; C not to scale. Photos: G. Oliver (A) and B. Páll-Gergely (B–D).