Chersaecia auffenbergi, Pall-Gergely, 2018

Páll-Gergely, Barna, 2018, Systematic revision of the Plectopylinae (Gastropoda, Pulmonata, Plectopylidae), European Journal of Taxonomy 455, pp. 1-114 : 29-33

Chersaecia auffenbergi sp. nov.

urn:lsid:zoobank.org:act:D15B11F6-EB4F-4699-B795-AD260B043E1B

Figs 14 A–B, 15A–B, 16A–B

Diagnosis

A medium-sized, sinistral, flat species with a concave dorsal surface (only the roughly wrinkled protoconch protrudes above the dorsal surface), rounded body whorl, dichotomous middle palatal plicae (the first and last are straight and simple) and two vertical lamellae on the parietal wall. Two horizontal plicae connect to the anterior lamella; the upper one is continuous with the apertural fold.

Etymology

The new species is named after Kurt Auffenberg, formerly of the Florida Museum of Natural History, who collected one of the samples and has assisted me with discussions in numerous publications.

Material examined

Holotype

THAILAND: 1 shell (D = 16 mm), Mae Hong Song Province , 6.2 km N of Soppong, along the road to Tham Lod Village, 19°34′ N, 98°9′ E, 20 Mar. 1988, Auffenberg, K. leg. ( UF 345566).

Paratypes

THAILAND: 3 shells, same data as for holotype ( UF 448572); 1 shell, same data as for holotype ( HNHM 97464); 1 shell, Mae Hong Son Province, 10 km NW of Ban Soppong, 19°33′11″ N, 98°11′32″ E, 24 May 1987, F.G. Thompson leg. ( UF 347263); 2 shells, Soppong, NE of Mae Hong Son, 27 May 2002, W. Proester leg., ex coll. W. Maassen (coll. PGB); 4 shells, same data as for preceding (coll. WM); 26 shells, Mae Hong Son Province, 8.9 km from Ban Sop Pong toward Mae Hong Son (road 1095), 19°33.075′ N, 98°11.925′ E, 810 m a.s.l., 10 Feb. 2015, A. Hunyadi leg. (coll. HA); 3 shells, Mae Hong Son Province, 6.2 km from Ban Sop Pong on road towards Tham Lod, 19°33.609′ N, 98°16.397′ E, 720 m a.s.l., 9 Feb. 2015, A. Hunyadi leg. (coll. HA); 18 shells, Mae Hong Son Province, 9.1 km from Ban Sop Pong towards Mae Hong Son, left side of road no. 1095, 19°33.123′ N, 98°11.694′ E, 785 m a.s.l., 9 Feb. 2015, A. Hunyadi leg. (coll. HA).

Additional material

THAILAND: 3 juv. shells, Mae Hong Son Province, 8.9 km from Ban Sop Pong, on road towards Mae Hong Son (road 1095), 19°33.075′ N, 98°11.925′ E, 810 m a.s.l., 10 Feb. 2015, A. Hunyadi leg. (coll. HA); 2 juv. specimens (preserved in ethanol: PL050 and PL051 used for molecular study and radula examined), same data as for preceding ( NHMW MO-112 221); 2 juv. shells, Mae Hong Son Province, 6.2 km from Ban Sop Pong on road towards Tham Lod, 19°33.609′ N, 98°16.397′ E, 720 m a.s.l., 9 Feb. 2015, A. Hunyadi leg. (coll. HA); 9 juv. /broken shells, Mae Hong Son Province, 9.1 km from Ban Sop Pong towards Mae Hong Son, left side of road no. 1095, 19°33.123′ N, 98°11.694′ E, 785 m a.s.l., 9 Feb. 2015, A. Hunyadi leg. (coll. HA).

Description

SHELL. Sinistral, brownish corneous, flat, only protoconch protrudes above dorsal surface; protoconch consists of 2.5–2.75 whorls, with fine granular surface, roughly, irregularly ribbed; dorsal side of teleoconch finely reticulated, sculpture on umbilical side weaker; ribs stronger than spiral lines on both dorsal and ventral surfaces; whorls 5.5–5.75, separated by a rather deep suture; aperture oval; peristome thickened and slightly reflected; parietal callus weaker than peristome; apertural fold in contact with parietal callus, gradually weakens towards parietal callus.

Two shells were opened. Parietal wall with two vertical lamellae; both ends of posterior lamella slightly elongated posteriorly; anterior lamella shorter and thicker than posterior lamella, connected to main and intermediate plicae; intermediate plica slightly longer than posterior lamella; main plica runs to apertural fold. Palatal wall with six plicae; first plica straight, longest and situated near suture; last plica curved downwards very slightly; middle plicae Y-shaped, with arms of Y pointing posteriorly.

MEASUREMENTS (in mm). D = 15.2–18.2, H = 4.8–5.2 (n = 4).

RADULA. Centrals with very small, triangular cusps; endocones of laterals subovoid; ectocones of first laterals larger than centrals; ectocones of marginals undivided; endocones of marginals divided at their middle by rather deep incision.

Differential diagnosis

Chersaecia auffenbergi sp. nov. can easily be distinguished by its Y-shaped palatal plicae, roughly ribbed protoconch and concave spire.

Distribution

The new species is only known from five localities across three sites, which are all situated in close proximity to one another in the northern part of Mae Hong Son Province, Thailand ( Fig. 17 ).

Figures

Fig. 14. Shells and protoconchs of species of Chersaecia Gude, 1899. A–B. C. auffenbergi sp. nov., holotype (UF 345566). C. C. goniobathmos (Ehrmann, 1922) comb. nov., lectotype (SMF 150100a). D–E. C. goniobathmos, paralectotype (SMF 150100c). F. C. feddeni (Blanford, 1865) comb. nov., syntype (NHMUK 1906.1.1.730). G. C. feddeni, holotype of P. ponsonbyi (Godwin-Austen, 1888) syn. nov. (NHMUK 1913.3.14.9). Scale bars: A, C–D, F–G = 10 mm; B, E = 1 mm. Photos: T. Deli (A), B. Páll-Gergely (B–E), H. Taylor (F–G).

Fig. 17. Distribution of plectopylid species in Northern Thailand. Legends: circle = Chersaecia auffenbergi sp. nov.; triangle = Chersaecia leiophis (Benson, 1860) (empty triangle shows the type locality of Plectopylis degerbolae Solem, 1966); empty square = Chersaecia perarcta simplex (Solem, 1966); cross = Chersaecia perarcta perarcta (Blanford, 1865); filled square = Chersaecia scabra sp. nov.; rhomb = Chersaecia densegyrata sp. nov.; the upper filled triangle also shows the locality of Naggsia oligogyra sp. nov.