Diaphera parini, Páll-Gergely & & Sutcharit & Chirasak, 2024

Páll-Gergely, Barna, , András Hunyadi, Sutcharit, & Chirasak, 2024, New and little-known Diapheridae of Cambodia and Thailand (Gastropoda: Stylommatophora: Streptaxoidea), Raffles Bulletin of Zoology 72, pp. 203-213 : 207

Diaphera parini , new species

( Figs. 2, 6E)

Type material.

Holotype. 1 shell ( Fig. 2A; SH = 3.2 mm, SW = 1.21 mm, AH: 0.81 mm, AW: 0.8 mm) ( CUMZ 14213 ), Thailand, Rayong Province, Khao Chamao District, rock wall behind Wat Tham Khao Bot , 70 m asl, 13°02.273′N, 101°38.120′E, coll. A. Hunyadi, 9 March 2023.

Paratypes. 1 shell ( Fig. 2B) (coll. HA), same information as holotype; 2 shells (coll. HA), same information as holotype.

Diagnosis. The smallest Diaphera species in Thailand and Cambodia, with an ovoid shell and five apertural barriers (a very strong parieto-angular lamella, blunt upper palatal tooth, a more pointed lower palatal tooth, slightly elongated columellar lamella, and a low, blunt basal tooth). The sympatric D. prima is much larger ( Fig. 6C, E), more spindle-shaped, has a different sculpture (strong riblets along the suture but smooth mid-whorls), and a longer detached portion ( “tuba ”). See also under D. pongrati , new species.

Description. Shell white, opaque to slightly translucent. Spire-whorls elongate ovoid with a deep suture; apex blunt; last and penultimate whorls of comparable width. Whorls 6.5; protoconch-teleoconch boundary not clearly visible; all whorls strongly convex (bulging); first juvenile peristome developed at ca. 2 whorls; last juvenile peristome present ca. 1.5–2 whorls behind adult peristome. Protoconch glossy, smooth. Teleoconch moderately glossy, with very fine, low, inconspicuous ribs; last ca. half whorl, but mostly the detached part ( “tuba ”) with somewhat stronger ribs, area around the umbilicus also with stronger ribs, not reaching the middle of the body whorl; last ca. 0.25 whorls detached, detached part short, thick, aperture not protruding beyond spire-whorl plane. Detached portion ( “tuba ”) slopes downward at an angle of about 40°. Upper suture continues to back side of sinulus without forming a keel, it bears a shallow groove on inner side, dividing the upper part of the detached portion in the middle; outer (lateral) side of detached portion without groove, but with a slight depression corresponding with the lower palatal tooth. Lower suture continues towards the peristome, forming a very blunt periumbilical keel, with a short, shallow depression on the umbilical side corresponding with the columellar lamella. Aperture axis slightly oblique to shell axis; aperture ovoid, nearly rectangular, with a narrow, strongly isolated sinulus. Sinulus opens slightly upwards. Parieto-angular lamella very strongly developed, extremely high, long, strongly oblique; outer tip slightly protruding; the entire lamella seems to be turning slightly towards columellar side. Upper palatal tooth blunt, but strong, lower palatal tooth situated much deeper and lower in position, more pointed than upper palatal tooth. Columellar lamella slightly elongated, situated deep inside the aperture, its position corresponds with the end of the groove on the umbilical side of the tuba. Basal tooth low, blunt, only slightly indicated. Peristome thickened, strongly expanded (except for the sinulus area), its margin slightly reflected. Umbilicus closed.

Measurements (in mm). SH = 3.1–3.4, SW = 1.21–1.27, AH: 0.74–0.81, AW: 0.75–0.8 (n = 3).

Etymology. This new species is named after and dedicated to our friend Parin Jirapatrasilp, Thai malacologist.

Distribution. This species is known only from the type locality ( Fig. 6A).