Luzonocoptis angulata Pall-Gergely & Hunyadi

Pall-Gergely, Barna, Hunyadi, Andras & Asami, Takahiro, 2017, A new diplommatinid genus and two new species from the Philippines (Gastropoda, Caenogastropoda, Cyclophoroidea), ZooKeys 678, pp. 1-10 : 1-2

Luzonocoptis angulata Pall-Gergely & Hunyadi sp. n. Figures 1 I–P, 2G, I

Type material.

Philippines, Luzon, Cagayan Province, 10 km southeast from Gattaran, Barangay Naddungan, environment of the Ar-Aro Cave, rock wall facing east, 90 m, 18°4.477'N, 121°44.128'E, leg. Hunyadi, 08.01.2014. HNHM 99996 (holotype, H = 9.1 mm, D = 2.1 mm), HNHM 99998 (3 paratypes), HA/238 paratypes, PGB/3 paratypes.

Type locality.

Philippines, Luzon, Cagayan Province, 10 km southeast from Gattaran, Barangay Naddungan, environment of the Ar-Aro Cave, rock wall facing east, 90 m, 18°4.477'N, 121°44.128'E.

Diagnosis.

A tall, yellowish, moderately slender diplommatinid with club-shaped apex, widely spaced, sharp ribs on the last whorl, angled lower whorls, strongly expanded peristome that is slightly oblique to the shell axis, and a weak interrupted columellar lamella.

Description of the shell

(Figs 1 I–P, 2G, I). Shell sinistral, tall, very slender; apex thickened; penultimate whorl wide, body whorl constricted, peristome strongly expanded; whorls 14-15; shell colour overall pale yellow or corneous to light reddish, sometimes seemingly darker due to the desiccated body, subtranslucent; protoconch consists of approximately 1.25-1.5 whorls, finely pitted; first whorls of teleoconch conspicuously narrower than teleoconch; first whorls of teleoconch with low, irregular growth wrinkles, which gradually change to a scarcely, regularly ribbed surface; some weak spiral striation visible between ribs; ribs are strongest on last whorl, where they are sometimes lamella-like; upper whorls slightly concave or not concave, slowly, rather regularly increasing; constriction very deep, situated between penultimate and last whorl (just behind parietal part of peristome); deep constriction results in formation of a conspicuous post-constriction bay (widened area just anterior to operculum); last whorl conspicuously narrower than preceding whorl; lower 3-4 whorls slightly keeled at their middle; aperture moderately oblique to shell axis, rounded, with a weak columellar lamella visible from standard apertural view; columellar lamella low, interrupted; its inner, separate, elongated tubercle-like part situated inside post-constriction bay; no other plicae or lamellae found; peristome overall strongly expanded but varies from not reflected to slightly reflected; boundary between inner and outer peristome clearly visible due to sharp edge of inner peristome; outer peristome mostly responsible for ex panded profile of peristome; upper, parietal part of peristome is attached to penultimate whorl, although expanded part extends above penultimate whorl; umbilicus absent.

Measurements.

Shell height: 7.8-9.3 mm; shell width: 1.8-2.1 mm; aperture height: 2.2-2.6 mm (n = 5).

Operculum. Unknown.

Etymology.

The specific epithet angulata (Latin: angled) refers to the keeled lower whorls, which distinguishes this species from L. antenna sp. n.

Habitat and distribution.

Empty shells were found at the base of a limestone rock wall. This species is known from the type locality only, which is situated ca. 34 km in a straight line from the type locality of L. antenna sp. n.

Comparisons.

See under Luzonocoptis antenna sp. n.