Pincerna mouhoti (L. Pfeiffer, 1862 )

Páll-Gergely, Barna, 2023, Revision of the Alycaeidae of China, Laos and Vietnam (Gastropoda: Cyclophoroidea) II: The genera Alycaeus and Pincerna, Zootaxa 5249 (2), pp. 253-276 : 266-267

Pincerna mouhoti (L. Pfeiffer, 1862)

( Fig. 10 )

Alycaeus mouhoti Pfeiffer, 1862: 275 , pl. 36, figs 1–2.

Alycaeus (Alycaeus) mouhoti — Kobelt, 1902: 347.

Alycaeus mouhoti —Páll-Gergely et al., 2017: 10.

Pincerna mouhoti — Páll-Gergely et al., 2020: 180 .

Type material. Lao Mountains , leg. Mr. Mouhot, ex coll. Museum Cuming, NHMUK 20170120 /2 shells (probably syntypes, Fig. 10A–E ) .

Additional material examined. LAOS: Luang Prabang, coll. H. Counillon, RBINS/1 ; Xaysomboun Province, Long Tieng 1 km E on road to Sanasomboun, small ponor, cave deposit at foots of cliffs right side of the road, 19°5.887′N, 102°56.325′E (locality code: JG31 ), leg. Grego, J., 24 February 2017, JG/1; Central Laos , Luang Prabang province, ca. 6 km E of Muang Xiang Ngeun , under rocks in young forest with few old trees above spring on limestone outcrop, 19°44.772′N, 102°15.284′E, alt. 350 m (locality code: 36L06), leg. A. Abdou & I. V Muratov , 21 November 2006, MNHN-IM-2012-27293 / 2; Central Laos , Luang Prabang province, Phou Xuang mountain, ca. 1.5 km NE of Ban Lak Sip , ca. 5 km SE of Luang Prabang, under rocks and logs in old secondary forest under cliff, 19°51.605′N, 102°11.081′E, alt. 640 m (locality code: 39L06), leg. A. Abdou & I. V Muratov , 24 November 2006, MNHN-IM-2012-27302 / 30 + 2 juvenile shells; Central Laos , Luang Prabang province, ca. 6 km N of Phou Khoun , under rocks in dry secondary forest under and above cliff, 19°29.653′N, 102°24.470′E, alt. 1244 m (locality code: 34L06), leg. A. Abdou & I. V . Muratov , 16 November 2006, MNHN-IM-2012-27294 / 2; Central Laos , Luang Prabang province, ca. 17 km SE of Muang Xiang Ngeun, along small stream on the left side (~2 km S) of Nam Khan , on and under rocks and logs in old forest with banana, 19°40.188′N, 102°18.538′E, alt. 525 m (locality code: 13L06), leg. A.Abdou & I. V Muratov , 31 October 2006, MNHN-IM-2012-27292 /7; Xiangkhoang Province , caverns among boulders at large sinkhole below small settlements (5 houses about 6 km SW of Bank Knong), 1062 m a.s.l., 19°23.265′N, 102°58.521′E (locality code: JG29 ), leg. Grego, J., 23 February 2017, JG/72 ( Fig. 10Q–T ) ; Luang Prabang Province, 3.1 km from Nong Khiaw towards Pak Xeng, Tham Pha Toke , environment of the cave, 345 m a.s.l., 20°33.215′N, 102°37.722′E (locality code: 2019/114), leg. A. Hunyadi, 5 October 2019, HA/1 . VIETNAM: Ngh ệ An Province, northwester edge of Anh SƠn towards Con Cuông , next to a cement company, left side of the road, 30 m, 18°56.574′N, 105°03.609′E (locality code: 2012/8), leg. Hunyadi, A., 15.05.2012, HA/2 ( Fig. 10M–P ) ; Dien Bien Province, ca. 12 km from Tuan Giao to Dien Bien Phu (left side off road), 21°31.483′N, 103°21.792′E (locality code: Vn 10-111), leg. Hemmen, 10 October 2010, HE/1+1 ; Thang Hoa Province, eastern part of the Ben En National Park (outside the Park ), road to the lake (ca. 22 km SE Yen Cat), 19°36.785′N, 105°34.513′E (locality code: Vn 12-285), leg. Hemmen, Ch., 07 October 2012, HE/4; Vietnam , Ninh Binh Province, Cuc Puong National Park , 290 m, near 20°18.435′N, 105°38.885′E (locality code: WVD2 ), leg. W. van Devender, 14–17 May 2011, VNMN/1 ( Fig. 10U–X ) ; Thanh Hoa Province, Ben En National Park (between Yen Cat to Thanh Hoa) ca. 1 km off road no. 45, 45.7 km to Thanh Hoa (right off road), 19°40.421′N, 105°31.066′E (locality code: Vn 12-226B), leg. Hemmen, 05 October 2012, HE/4 ( Fig. 10I–L ); Same data, 20 October 2011, HE/3 ; Thanh Hóa Province, Như Thanh District, Hải Vân, Hang Lò Cao Kháng Chi ḗn, vicinity of cave entrance, 22 m a.s.l., 19°37.079′N, 105°34.629′E (locality code: 2020/41), leg. Hunyadi, A., 11 February 2020, Coll. HA /1 ; Thanh Hóa Province, 42.7 km south from centre of Ng ọc Lặc on the road Hồ Chí Minh, Thư ờng Xuàn District , Tân Thành, B ản Nha , estern edge of the village, 65 m a.s.l., 19°45.709′N, 105°25.537′E (locality code: 2020/39), leg. Hunyadi, A., 14 February 2020, Coll. HA /7 ; Thanh Hóa Province, Như Thanh District, H ải Long, Vườn Qu ốc Gia B ḗn En, H ồ Sȏng M ực 2, northern side, 20 m a.s.l., 19°37.817′N, 105°32.941′E (locality code: 2020/42), leg. Hunyadi, A., 15 February 2020, Coll. HA /1 ; SƠn La Province, right side off road Mộc Châu to SƠn La, 20°52.567′N, 104°35.310′E (locality code: Vn 11-104), leg. Ch. Hemmen, 14 October 2011, HE/3 ; Thanh Hoa Province, km 585 on road no. 15 Yen Cat to Ngoc Lac 1 km right off road no. 15, 19°45.589′N, 105°25.521′E (locality code: Vn 12-268), leg. Ch. Hemmen, 14 April 2012, HE/1 ; SƠn La Province, Mộc Châu 5 km towards SƠn La, right side of the road no. 6, 755 m, 20°52.551′N, 104°35.318′E (locality code: 2012/60), leg. Hunyadi, A., 06 June 2012, HA/3 ( Fig. 10E–H ) ; SƠn La Province, Mộc Châu Disctrict, Vân Hồ, northwestern edge of Pa Cốp towards Bó Nhàng , 980 m, 20°46.001′N, 104°45.203′E (locality code: 2020/24), leg. Hunyadi, A., 10 February 2020, HA/1 ; SƠn La Province, Mộc Châu, Hang DƠi, vicinity of cave entrance, 865 m a.s.l., 20°50.960′N, 104°38.335′E (locality code: 2020/26), leg. Hunyadi, A., 11 February 2020, Coll. HA /1 ; SƠn La Province, 24 km northwest from centre of SƠn La towards Thu ận Châu, Chi ễng Pấc, left side of the road, 565 m a.s.l., 21°24.707′N, 103°45.794′E (locality code: 2020/13), leg. Hunyadi, A., 7 February 2020, Coll. HA /2 .

Diagnosis. A medium-sized to large, yellowish or rarely reddish species with very finely reticulated R1, smooth and long R2, R3 with blunt swelling and weak inner peristome.

Description. Shell yellowish or rarely reddish when fresh; slightly wider than high; protoconch smooth, glossy, consists of 1.5, or slightly more whorls; R1 consists of 2 whorls, it is rather glossy, with irregular, low ribs and extremely fine spiral striation (most easily visible near the suture); R2 and R3 of ca. 110 degrees combined, they are of the same length; R2 without elevated ribs; thinner light and thicker dark stripes alternate; cross sectional view not examined; constriction between R2 and R3 deep; R3 rather matte, with low swelling; aperture conspicuously large, rounded; outer peristome expanded (especially in direction of umbilicus), but not reflected; boundary between inner and outer peristomes not conspicuous; umbilicus open, narrow, partly covered by peristome.

Measurements (in mm). D = 5.7–7.5, H = 5.2–7.0 (multiple populations, n = 14).

Operculum. The operculum of two specimen were examined (Cuc Phuong N. P., VNMN; MNHN-IM-2012- 27302 , see Fig. 3C–G ). Operculum calcareous, relatively thick, slightly concave (strongly concave with elevated inner rim in MNHN-IM-2012-27302 ); inner surface multispiral without elevated nipple; outer surface multispiral, matte .

Variation in specimens. The examined shells show some variability in terms of shell colour, shell size, length of R2 (moderately long to long), and the intensity of ribbing on R1 (entirely smooth to finely ribbed). In some specimens the inner and outer peristomes can be as distinct as in P. vanbuensis .

Differential diagnosis. See under A. vanbuensis .

Distribution. The species was described from “Lao Mountains, Camboja ” (most probably the vicinity of Louang Prabang). Newly collected specimens from Northern Vietnam and Northern Laos were examined here ( Fig. 11 ).

Figures

FIGURE 3. Opercula of Alycaeus Baird, 1850 and Pincerna Preston, 1907 species. A–B: Alycaeus eydouxi Venmans, 1956 (V142, NHM); C–D: Pincerna mouhoti L. Pfeiffer, 1862 (Cuc Phuong NP, VNMN); E–G: Pincerna mouhoti, MNHN-IM-2012- 27302; H–I: Pincerna vanbuensis (Bavay & Dautzenberg, 1900) (2012/60). Scales represent 1 mm.

FIGURE 10. Pincerna mouhoti (L. Pfeiffer, 1863). A–D: Syntype (NHMUK 20170120); E–H: 2012/60; I–LC: Vn11-226; M–P: 2012/8; Q–T: JG29; U–X: Cuc Phuong NP, VNMN. Photos: H. Taylor (A–D) and B. Páll-Gergely (E–X).

FIGURE 11. Distribution of Pincerna mouhoti (L. Pfeiffer, 1863). The map was made using Google Earth Pro.