Pseudopomatias maasseni Páll-Gergely & Hunyadi, 2015

Páll-Gergely, Barna, Fehér, Zoltán, Hunyadi, András & Asami, Takahiro, 2015, Revision of the genus Pseudopomatias and its relatives (Gastropoda: Cyclophoroidea: Pupinidae), Zootaxa 3937 (1), pp. 1-49 : 37-38

Pseudopomatias maasseni Páll-Gergely & Hunyadi , n. sp.

Figs 6 F, 13A–C.

Diagnosis. A large, slender, almost cylindrical species with thick apertural margin, rather flattened whorls and characteristic ribbing around the umbilicus (every second ribs are prominent).

Description. Shell brownish or greyish, slender turriform or cylindrical, usually the penultimate whorl is the widest, or the last three whorls are of almost the same width; the 9.75–10.25, slowly increasing, moderately bulging or sometimes rather flat whorls are separated by shallow suture; suture is a bit deeper between the apical whorls; last whorl conspicuously flatter than the penultimate whorls; protoconch matt, finely granulated; teleoconch finely, regularly ribbed; last half whorl is irregularly ribbed; on the basal side of the shell (around the umbilicus) every second ribs are wider and stronger; aperture usually rounded with not or very slightly angled columellar-parietal transition and slightly angled parietal-palatal transition; peristome very much thickened but not reflexed, consists of two circles separated from each other; the circles are of different width, the outer is thicker than the inner one; suture shallow between the circles.

Measurements (in mm). D: 11.4–13.6, H: 4.0–4.7 (sample from the type locality, n=4), H: 14.6–14.7, D: 4.4–4.5 (NHMUK 20130399, n=2).

Differential diagnosis. P. maasseni n. sp. can be distinguished by other members of the genus by the tall, slender shell, shallow suture, rather quadrangular whorls and the every second elevated ribs on the base. Also see under P. amoenus and Table 6 .

Material. Vietnam, Sơn La Prov., Hà Nội 156 km towards Mộc Châu, right side of the road nr. 6., rocky wall, 1110 m, 20°46.085'N 104°53.888'E, leg. Hunyadi, A., 0 6.06.2012, HNHM 98833 (holotype) HA/28 paratypes (2012/62; one of them was used for DNA analysis), PGB/2 paratypes; Vietnam, Sơn La Prov., Hà Nội 156 km towards Mộc Châu, left side of the road nr. 6, rocky wall, 1110 m, 20°45.993'N 104°53.868'E, leg. Hunyadi, A., 0 6.06.2012, HA/1 paratype; Vietnam, Sơn La Prov., ca. 32 km from Mộc Châu, to Hà Nội (old road), 20°47.351'N, 104°50.063'E, leg. Hemmen, Ch. & J., 0 2.04.2010., HE/6 paratypes, PGB/2 paratypes; same locality, 15.10.2011., HE/4 paratypes; same locality, 0 7.10.2010., HE/3 paratypes; Vietnam, Son La Prov., ca. 34 km from Moc Chau to Mai Chau, 20°45.219'N, 104°54.458'E, leg. Hemmen, Ch. & H., 15.10.2011., HE/1 paratype; China, Guangxi, Napo Xian, Pohe Xiang, left side of road to Longhe, 1223 m, 23°20.84445'N, 105°54.60324'E, leg. Ohara, Okubo & Otani, 10.01.2006. OK/1 paratype; Tonkin, J.J. MacAndrew coll, NHMUK 20130398/1 paratype; Tonkin, Phong Tho, J.J. MacAndrew coll, NHMUK 20130399/2 paratype; Tonkin, Phong Tho, E. R. Sykes coll, Acc. no. 1825, NHMUK 20130400/2 paratype; Tonkin, Phong Tho, B. R. Lucas coll, Acc. no. 2351, NHMUK 20130401/1 paratype; Tonkin, Phong Tho, J. J. MacAndrew coll, Sr. F. 21/4/09, NHMUK 20130402/2 paratypes; Tonkin, Phong-Tho, coll. C. Dosch ex H. Rolle, SMF 192249/2 paratypes; Tonkin, Muong-Hum, coll. Denis 1945, MNHN 2012-26941/4 paratypes (mixed sample with P. amoenus : MNHN 2012-26940); Tonkin, Phong-Tho, coll. Denis 1945, MNHN 2012-26943/10 paratypes; Tonkin, Phong-Tho, coll. Staadt 1969, MNHN 2012-26948/4 paratypes; Tonkin, leg. Messager, MNHN 2012-26955/30 paratypes; Tonkin, Muong-Hum, leg. Messager, MNHN 2012- 26957/1 paratype (mixed sample with P. amoenus : MNHN 2012-26957); Indochine, leg. Messager, MNHN 2012- 26985/1 paratype; Tonkin, Phong-Tho, NHMUK 1910.9.28.172–173, NHMUK 1909.7.2.26, NHMUK 1909.10.19.71–72 (altogether 5 paratypes) (labelled as "co-type" of buliminiformis); Vietnam, Bac Can Prov., ca. 1 km from Ba Bé N. P. headquarters to Ba Bé Lake, ca. 286 m, 22°24.829'N, 105°37.652'E, leg. Hemmen, Ch. & H., 20.10.2010., HE/2 paratypes; Vietnam, Ha Giang Prov., ca. 7.5 km from Dong Van to Meo Vac (right side off road), 23°14.906'N, 105°23.445'E, leg. Hemmen, Ch. & H., 18.10.2010., HE/1 paratype; Vietnam, Son La Prov., 6 km from Son La to Thuan Chau (left side off road), 21°19.502'N, 103°53.055'E, leg. Hemmen, Ch. & H., 0 8.10.2010., HE/1; Tonkin, Phong-Tho, NHMUK 1909.7.2.32/1 paratype (labelled as " syntype " of buliminiformis var. minor ); Tonkin, Phong-Tho, NHMUK 1910.9.28.170–171/2 paratypes (labelled as " syntype " of buliminiformis var. minor ).

Type locality. Vietnam, Sơn La Prov., Hà Nội 156 km towards Mộc Châu, right side of the road nr. 6., rocky wall, 1110 m, 20°46.085'N 104°53.888'E.

Etymology. The new species is dedicated to and named after Wim J. M. Maassen, malacologist, the friend of the first author, the outstanding expert of South-East Asian land snail fauna.

Distribution ( Fig. 15 ): The species is known from Northern Vietnam (Sơn La, Lai Châu and Lào Cai Provinces) and from one locality in Guangxi, China.

Remarks. In museum collections Pseudopomatias maasseni n. sp. was frequently in mixed lots with P. amoenus . Some samples (MNHN 2012-26941, MNHN 2012-26957, MNHN 2012-26985) are characterized by very robust, corpulent shells. The species is still recognisable and can be assigned to this species, and they are distinguishable from P. amoenus on the basis of relatively flat whorls and the every second stronger ribs around the umbilicus.

A single, straight, long plica is visible above the aperture in the fresh, translucent shells from the type locality. This plica has not been detected in specimens from other sites.

The shells from the Vietnamese Hà Giang and Bắc Kạn Provinces and the single Chinese specimen has the last whorl slightly flattened from "dorsobasal" direction. This results in the formation of a blunt keel, which nevertheless situated closer to the umbilicus than that of the genus Vargapupa gen. n. This keel-like structure in some P. maasseni n. sp. shells and the strong keel of Vargapupa gen. n. are probably not homologous.

Figures

FIGURE 6. Apertural margin of Pseudopomatias species. A. Pseudopomatias nitens n. sp., Tonkin, coll. Denis 1945, MNHN 2012 - 26931, paratype; B. P. sophiae n. sp., Tonkin, pris du Col de Nuages (2000 m altitude), leg. Messager, MNHN 2012 - 26952, paratype; C. P. amoenus Möllendorff 1885, same data as before; D. P. linanprietoae n. sp., Laos, Luang Prabang Prov., Nong Kiau, excoll Jose Ahuir Galindo, paratype, coll. PGB; E. P. nitens n. sp. from Sichuan, same data as before; F. P. maasseni n. sp., holotype.

FIGURE 15. Distribution of Pseudopomatias and Vargapupa n. gen. species. Empty triangle, top up: Vargapupa biheli n. sp.; filled triangle, top down: Vargapupa oharai n. sp.; empty square: Pseudopomatias maasseni n. sp., open circle: P. sophiae n. sp., closed circle: P. linanprietoae n. sp.