Laotia luongi, Páll-Gergely & Hunyadi, 2021

Páll-Gergely, Barna & Hunyadi, András, 2021, A new species and a new subspecies of Laotia Saurin, 1953 (Gastropoda: Caenogastropoda: Alycaeidae) from Sơn La Province, Vietnam, Raffles Bulletin of Zoology 69, pp. 118-123 : 121

Laotia luongi , new species

( Fig. 3A, B )

Type material. Holotype (D: 5.1 mm, H: 2.9 mm) (VNMN- Z-Inv.000220), Vietnam, SƠn La Province, Yên Châu District, Chi ềng On Commune , Tr ạm Hốc Village , Nh ả Nhung Cave , around the cave, 970 m a.s.l., 20°59.483′N, 104°11.270′E (locality code: 2020/20), coll. A. Hunyadi, H. V. Luong, J.U. Otani & S. V. Pham, 9 February 2020.

Paratypes. 5 adult shells (coll. HA), same data as holotype ; 8 adult broken shells (coll. HA), same data as holotype .

Additional material. 5 juvenile shells (coll. HA), same data as holotype .

Description. Shell dextral, depressed, 4.25–4.75 whorls; shell shape and size matches L. christahemmenae christahemmenae : approximately quarter of last whorl turns obliquely upwards; aperture directed towards apex; protoconch elevated (more elevated than it would be expected from the shell shape), 1.25–1.5 whorls, finely granular, without any notable sculptural elements; teleoconch with widely-spaced, straight, lamella-like, fragile ribs; last whorls with 36–62 ribs (n = 4); area between ribs glossy without spiral lines; rib density constant from initial whorls until the aperture; umbilicus relatively wide, ca. one third of minor shell diameter; aperture rounded; inner peristome slightly protruding, expanded, smeared onto the penultimate whorl; outer peristome strongly expanded, slightly reflected; operculum unknown.

Measurements (in mm). D: 4.3–5.1, H: 2.3–2.9 (smallest and largest shells measured).

Differential diagnosis. In shell size and shape this species is similar to L. christahemmenae . However, the latter species has much denser, bent ribs (straight in the new species) and the area behind the peristome is without ribs (ribbed in the new species). Laotia pahiensis ( Fig. 3C ) also possesses ribs behind the peristome and has widely-spaced, straight ribs. Nevertheless, it is much smaller than the new species, and its aperture is less distorted upwards.

Etymology. This new species is dedicated to and named after our much-valued friend, Hào Văn LƯƠng, who helped during field collection.

Distribution. Laotia luongi , new species, is known only from the type locality in SƠn La Province, Vietnam ( Fig. 2 ).

Figures

Fig. 3. Shells of Laotia Saurin, 1953 species. A, Laotia luongi, new species, holotype (VNMN-Z-Inv.000220); B, L. luongi, new species, paratype (coll. HA); C, syntype of Laotia pahiensis Saurin, 1953 (MNHN-IM-2000-28217. Photos: B. Páll-Gergely (A, B), M. Caballer (C, downloaded from the website of MNHN).

Fig. 2. Distribution of Laotia Saurin, 1953 species in Vietnam. Triangle: Laotia christahemmenae phami, new subspecies; inverse triangle: Laotia luongi, new species; square:Laotia christahemmenae christahemmenae Páll-Gergely, 2014 (filled square represents the type locality).