Chersaecia smithiana (Gude, 1897) Páll-Gergely, Barna, 2018

Páll-Gergely, Barna, 2018, Systematic revision of the Plectopylinae (Gastropoda, Pulmonata, Plectopylidae), European Journal of Taxonomy 455, pp. 1-114 : 28-29

Chersaecia smithiana (Gude, 1897) comb. nov.

Figs 6 E–F, 7K–L

Plectopylis smithiana Gude, 1897c: 274 , fig. 38a–d [“Attaram, Burma ”].

Plectopylis smithiana – Gude 1897j: 44–45, fig. 1a–d.

Plectopylis (Endoplon) smithiana – Gude 1899d: 148; 1899e: 175; 1914b: 115–117, fig. 56a–d.

Diagnosis

A large, dextral, robust, flat species (only protoconch protrudes over dorsal surface) with one lamella, two short plicae anterior to the lamella, and a long apertural fold connected to the elevated parietal callus.

Material examined

Syntypes

MYANMAR: 2 shells, Attaram valley, Theobald leg. ( NHMUK 1888.12.4.1555–6).

Description

SHELL. Dextral, strongly built, greyish-corneous, flat, but protoconch conspicuously protrudes above dorsal surface; protoconch conspicuously large (3.25–3.5 whorls, n = 2), matt, with dense, irregular, wavy wrinkles; teleoconch finely, irregularly wrinkled; dorsal side and inside umbilicus with some reticulated sculpture; whorls 5.5–5.75 (n = 2); teleoconch whorls separated by a deep suture, embryonic whorls by a shallow suture; periphery of body whorl seemingly smooth (but very finely wrinkled under higher magnification); aperture rounded, sinulus widened; peristome expanded, strongly reflected and strongly thickened; parietal callus blunt but elevated, strongly S-shaped; apertural fold connected to parietal callus, very long, its end not even visible by oblique view into aperture.

The parietal plicae were observed in one opened shell, whereas the palatal ones in the other, intact shell. Parietal wall with one curved lamella, which has both the upper and lower ends elongated posteriorly, two small denticles anterior to the lamella (one above, one below), and a short lower plica under the lamella. Palatal plicae six; first and sixth straight, second very long and straight, remaining ones depressed Z-shaped, with an additional denticle above posterior ends of each plica.

MEASUREMENTS (in mm). D = 26.3–26.8, H = 10.6–11.1 (NHMUK 1888.12.4.1555–1556, n = 2).

Differential diagnosis

See under Chersaecia brachyplecta .

Distribution

Chersaecia smithiana is known from the type locality only.

Remarks

In the original description, Gude (1897c) mentioned that he examined two shells in the British Museum, one of which was opened by him. Furthermore, Gude examined an additional shell, which was also collected by Theobald, but received from Miss Linter. I examined the two shells in the NHM. According to the original description, Gude’s drawing of the parietal plication ( Gude 1897c: fig. 38d) illustrates the opened shell in the NHM. However, the lower plica is absent in the drawing, whereas the specimen itself shows a prominent lower plica. The reason for this discrepancy is unknown.

Figures

Fig. 6. Shells and protoconchs of Chersaecia Gude, 1899. A–B. C. austeni (Gude, 1899), lectotype (NHMUK 1903.06.01.1014.1). C–D. C. brachyplecta (Benson, 1863) comb. nov., syntype (NHMUK 1954.6.2.282). E–F. C. smithiana (Gude, 1897) comb. nov., syntype (NHMUK 1888.12.4.1555). Scale bars: A, C, E = 10 mm; B, D, F = 2 mm. All photos: H. Taylor.