Pseudopomatias phrunoi Páll-Gergely & Grego 2019, new species

(Figs. 3, 4)

Type material. Holotype (H: 7.1 mm, D: 2.6 mm, Figs 3A–G) (HNHM 104396), Myanmar, Kayah State, Hpruso distr., Maw Thi Do Village, Entrance of Phruno River Cave, 19°22.744′N, 97°2.570′E, coll. J. Grego, 12 December 2019; figured paratype (HNHM 104398a, Figs 3H–M), same data as holotype; figured operculum, paratype (HNHM 104398b, Figs 4A–B) same data as holotype; figured paratype (HNHM 104398b, Fig. 4C) same data as holotype; 2 paratypes (SMF 356926), same data as holotype; 2 paratypes (NHMUK 20190574), same data as holotype; 1 paratype (ZRC.MOL.015632), same data as holotype; 13 paratypes (JG/13), 8 juvenile shells (not paratypes, JG/8), same data as holotype; 9 paratypes (JG/9), Myanmar, Kayah State, Hpruso distr., Maw Thi Do, road towards Han Li Village, Rocks above bridge over Phruno River, 19°23.011′N, 97°2.108′E, coll. J. Grego, 12 December 2019; 9 juvenile shells (not paratypes, JG/9), same data as preceding; 4 paratypes (JG/4), Myanmar, Kayah State, Hpruso distr., Maw Thi Do, road towards Han Li Village, under bridge over Phruno River, 19°22.966′N, 97°2.153′E, leg. J. Grego, 12 December 2019; 3 juvenile shells (not paratypes, JG/3), same data as preceding. Diagnosis. A small to medium sized, brownish, slender turriform-spindle shaped species with strong ribs, strongly reflexed peristome and plicae half whorl behind the peristome.

Description. Shell yellowish corneous to reddish brown, slender turriform to slightly spindle-shaped, last two whorls are widest in apertural view; body whorl not exactly rounded but slightly flattened (most clearly visible from lateral view, Fig. 3D, 3J); whorls 8.5–9.75, moderately bulging; boundary between protoconch and teleoconch hardly discernible, supposed size of protoconch ca. 2 whorls; first half whorl of protoconch smooth, all other whorls of protoconch and teleoconch regularly ribbed (even behind peristome); ribs blunt, triangular in cross section, no additional fine surface structure visible; aperture rounded with smooth (not angled) columellar-parietal and slightly angled parietal-palatal transitions; peristome white, strongly reflected, consisting of a thinner, slightly protruding inner peristome and a thicker and reflected outer peristome; boundary between inner and outer peristomes relatively clearly visible (e.g., Fig. 3F, 3L); parietal callus well developed, but slimmer than other parts of peristome; three short plicae situated approximately half whorl behind peristome (ca. above the umbilicus) (Figs. 3B, 3F, 4C); lowest two plicae positioned equally deep in the spire (measured by the radial ribs on the outside of the shell), upper one situated somewhat more anteriorly (i.e., closer to the aperture); lowest plica (the one situated closes to umbilicus) short, but elevated, middle one ca. twice as long as lowest one, also elevated; uppermost one weaker (less elevated than other two); plicae correspond with a low, blunt columellar lamella, which is visible only after opening the shell; operculum probably stops before (anterior to) plicae and lamella; umbilicus present, very slightly open, slit-like.

Operculum (Fig. 4A, B). A single operculum was found in an empty shell. It is thin, proteinaceous (“horny”), multispiral, inner surface (Fig. 4B) with a very small central nipple.

Measurements (in mm). H = 7.1–10.1, D = 2.7–3.2 (n = 5).

Differential diagnosis. Pseudopomatias phrunoi, new species differs from the nearby occurring P. caligosus by the more slender shell, the less bulging whorls, more expanded peristome, the lack of fine spiral striation between the ribs, and the presence of plicae approximately a half whorl behind the peristome. Internal plicae were reported in P. reischuetzi Páll-Gergely in Páll-Gergely et al., 2015 from the Naga Hills, India, P. linanprietoae Páll-Gergely in Páll-Gergely et al., 2015 from Laos, and P. nitens from China and Vietnam. Pseudopomatias linanprietoae is probably the most similar to P. phrunoi, new species due to its strongly reflected peristome, but it has a wider triangular shell than that of P. phrunoi, new species with more bulging whorls, the plicae are situated closer to the peristome (ca. quarter whorl behind), and are arranged differently. Pseudopomatias reischuetzi has a more corpulent shell, a peristome that is not reflected, and the palatal part of its aperture is very long and straight, resulting in a nearly triangular aperture shape. Pseudopomatias nitens has a wider shell, a comparatively larger aperture, and a not or only slightly reflected peristome.

Etymology. This species is named after the Phruno River, which flows near the known localities.