Pseudopomatias caligosus, Páll-Gergely & Hunyadi, 2018

Páll-Gergely, Barna & Hunyadi, András, 2018, Four new cyclophoroid species from Thailand and Laos (Gastropoda: Caenogastropoda: Alycaeidae, Diplommatinidae, Pupinidae), Zoosystema 40 (3), pp. 59-66 : 64

Pseudopomatias caligosus n. sp.

( Fig. 3 )

TYPE MATERIAL. — Thailand. Mae Hong Son Province, 9.1 km from Ban Soppong towards Mae Hong Son, left side of road # 1095, 785 m a.s.l., 19°33.123’N, 98°11.694’E, leg. Hunyadi A., 09.II.2015., HNHM 100176 (holotype), HNHM 100442 (figured paratype), coll. HA (17 paratypes + 9 juvenile shells [not paratypes]), coll. PGB, 2 paratypes .

ETYMOLOGY. — The specific epithet caligosus (Latin: covered with mist) refers to the nickname of the Thai Province Mae Hong Son (“city of three mists”).

TYPE LOCALITY. — Thailand, Mae Hong Son Province, 9.1 km from Ban Soppong towards Mae Hong Son, left side of road # 1095, 785 m a.s.l., 19°33.123’N, 98°11.694’E.

DIAGNOSIS. — Shell medium sized to large for the genus, slender turriform with regular ribs, very fine spiral striation (mostly on the upper whorls), and a reflected peristome.

DIFFERENTIAL DIAGNOSIS. — This new species is most similar to P. peguensis ( Theobald, 1864) in terms of shell size and the bulging whorls, but differs from that species in the less glossy shell, the much stronger ribs, and the reflected peristome. Pseudopomatias shanensis Páll-Gergely, 2015 also has less bulging whorls, a more

strongly expanded peristome and denser ribs with clearly visible spiral striation between them.

DISTRIBUTION. — This species is known from the type locality only.

DESCRIPTION

Shell off-white to yellowish, all examined shells covered in reddish soil; shell very slender turriform, widest at its base; the 8.5-9.25 (n = 5), strongly bulging whorls separated by deep suture; protoconch with 2.5 whorls, first c. 0.75 whorl very finely granulated; remaining whorls very finely, regularly ribbed; teleoconch also finely, regularly ribbed; ribs rather strong, with triangular cross section; upper whorls with very fine spiral and radial lines, visible only under strong magnification ( Fig. 3F ); spiral lines getting weaker and less regular on last c. 2 whorls (here area between ribs dominated by very fine radial lines, Fig. 3G ); aperture rounded with very slightly angled columellar-parietal transition and slightly more sharply angled parietal-palatal transition; peristome whitish, expanded and strongly reflected; inner peristome protruding in some specimens, but the boundary between inner and outer peristomes usually hardy visible.

Operculum

Proteinaceous (“horny”), thin, flat (not concave); outer surface multispiral without elevated lamina; inner surface glossy, with a small, but elevated ventral nipple.

Radula ( Fig. 3F )

Radula taenioglossate. Radular teeth arranged in v-shaped rows, each transverse row with seven teeth (2-1-1-1-2). Central (rachidian) tooth not constricted at its middle, with well-developed, slender, pointed central cusp and one smaller, pointed lateral cusp on each side; inner marginal (= lateral) teeth with four cusps, all pointed, central cusp being the largest; two outer marginal teeth with 4-4 slender, pointed cusps (except for the outermost cusp of outer marginal tooth, which is rather blunt triangular).

Measurements (in mm)

H = 9.7-12, D = 3.8-4.4 (smallest and largest shells measured).

Figures

FIG. 3. — Pseudopomatias caligosus n. sp.: A-E, photos of the holotype (HNHM 100176); F, radula of a paratype (HNHM 100442); G-H, outer (G) and inner (H) surface of the operculum of a paratype (HNHM 100442); I, SEM image of the 5th whorl (holotype); J, SEM image of the penultimate whorl (holotype). Photograph: Barna Páll-Gergely. Scale bars: A-E, 5 mm; F, 50 μm; G, H, 1 mm; I, J, 200 μm.