Laotia christahemmenae christahemmenae Páll-Gergely, 2014

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 : 120

Laotia christahemmenae christahemmenae Páll-Gergely, 2014

( Fig. 1A )

Laotia christahemmenae Páll-Gergely, 2014: 291 , fig. 3.

Laotia christahemmenae — Do et al., 2015: 120, fig. 2D (new records from SƠn La Province).

Material examined. 8 adult + 13 juvenile shells (coll. HA), Vietnam, SƠn La Province, 27 km ESE from centre of Phù Yên, MƯ ờng Do, Han Một Village , ca. 300 m south from the village, 810 m a.s.l., 21°11.731′N, 104°47.129′E (locality code: 2020/7), coll. A. Hunyadi, H. V. Luong, J.U. Otani & S. V. Pham, 6 February 2020; 1 photographed shell + 1 adult shell + 1 juvenile shell (VNMN-Z-Inv.000221), Vietnam, SƠn La Province, Mộc Châu District, Nȏng trƯờng Mộc Châu , Ngũ Đ ộng Bản Ȏn , around the cave, 895 m a.s.l., 20°52.489′N, 104°42.533′E (locality code: 2020/23 and 20200210A), coll. A. Hunyadi, H. V. Luong, J.U. Otani & S. V. Pham, 10 February 2020 ; 10 adult + 9 juvenile shells (coll. HA), same data as preceding ; 1 adult + 3 juvenile shells (coll. JUO), same data as preceding; 1 broken shell (coll. HA), Vietnam, SƠn La Province, Mộc Châu District, Vân H ồ, northwestern edge of Pa C ốp towards Bó Nhàng , 980 m a.s.l., 20°46.001′N, 104°45.203′E (locality code: 2020/24), coll. A. Hunyadi, H. V. Luong, J.U. Otani & S. V. Pham, 10 February 2020; 1 broken and corroded shell (MNHN- IM-2012-27224), 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, 1,244 m a.s.l. (locality code: 34L06), coll. A. Abdou & I. V. Muratov, 16 November 2006 ( L. cf. christahemmenae ) .

Measurements (in mm). D: 4.3–5.2, H: 2.5–2.8 (2020/23); D: 4.6–5.0, H: 2.6–2.8 (2020/7) (smallest and largest shells of each lot measured).

Distribution. Laotia christahemmenae christahemmenae is known from Ha Noi and SƠn La Provinces in northern Vietnam; its occurrence in Luang Prabang Province of Laos requires verification, see Remarks ( Fig. 2 ).

Remarks. In the original description only a strongly corroded holotype and a paratype with broken aperture were available, therefore the fine sculpture and intraspecific variability of this species could not be properly described. The newly collected specimens agree with the holotype in general shell shape and the absence of ribs behind the peristome; therefore they are treated conspecific. The holotype had ca. 86 ribs on the last whorl, whereas it was slightly more in most (but not all) shells of the newly examined populations (2020/23: 74–98 ribs/last whorl, n=3; 2020/7: 100–110 ribs/ last whorl, n=3). The rib morphology of the newly collected shells could also be examined. The first ca. 1.5 whorls of the teleoconch possess widely-spaced ribs. The rib density changes rather abruptly to denser ribbing, and remains such until the ribs disappear near the aperture. Ribs (even the ones on the initial teleoconch whorls) are bent in direction of their anterior neighbours (towards aperture), apart from the widely-spaced ribs on the first 1.5 teleoconch whorls the ribs nearly reaching each other. In case of L. luongi , new species, the ribs are straight.

The single shell from Luang Prabang province in Laos (MNHN-IM-2012-27224) is strongly corroded, its apex and body whorl are broken. It matches with other L. christahemmenae shells in general shell shape, size, and the absence of ribs behind the peristome. Therefore, until more material becomes available from the same locality, we provisionally identify these shells as Laotia cf. christahemmenae .

Figures

Fig. 1. Shells of Laotia Saurin, 1953 species. A, Laotia christahemmenae christahemmenae Páll-Gergely, 2014 (20200210A, VNMN-Z- Inv.000221); B–D, Laotia christahemmenae phami, new subspecies. B, holotype (VNMN-Z-Inv.000218); C, outer side of the operculum, coll. HA, paratypes; D, inner side of the operculum, coll. HA, paratype. All photos: B. Páll-Gergely.

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).