Diaphera pongrati, 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 : 204

Diaphera pongrati , new species

( Figs. 1, 6D)

Type material. Holotype. 1 shell, ( Fig. 1A; SH = 3.59 mm, SW = 1.3 mm, AH: 0.76 mm, AW: 0.76 mm) ( CUMZ 14212 ), Thailand, Rayong Province, Khao Chamao District, Wat Tham Khao Prathun , gorge above the temple, 115 m asl, 13°07.439′N, 101°35.850′E, coll. A. Hunyadi, 9 March 2023.

Paratypes. 1 shell ( Fig. 1B) ( CUMZ 14214 ), same information as holotype ; 1 juvenile shell ( Fig. 1C) ( CUMZ 14215 ), same information as holotype ; 1 juvenile shell ( Fig. 1D) (coll. HA), same information as holotype; 13 shells (coll. HA), same information as holotype.

Diagnosis. A small Diaphera species with a glossy, ovoidconical shell, fine ribs along the suture, and four apertural barriers (very strong parieto-angular lamella, blunt upper palatal tooth, more pointed lower palatal tooth, denticle-like columellar lamella). The sympatric D. prima is much larger ( Fig. 6C, D), has a blunter apex, ribs along the suture in nearly the entire teleoconch, a more elongated columellar lamella, and possesses a basal tooth. Diaphera parini , new species has a more ovoid, corpulent shell, finely ribbed shell surface, a shorter detached part ( “tuba ”), a higher (more elevated) and more curved parieto-angular lamella, an elongated columellar lamella, and possesses a tiny basal tooth.

Description. Shell whitish, translucent. Spire-whorls ovoidconical with a deep suture; apex pointed; penultimate whorl widest in frontal view, or last and penultimate whorls of comparable width. Whorls 6.75–7; protoconch-teleoconch boundary not clearly visible; all whorls strongly convex (bulging); first juvenile peristome developed at ca. 2 whorls; last juvenile peristome present ca. 2 whorls behind adult peristome. Protoconch glossy, smooth. Teleoconch also glossy and smooth, without ribs, except for a few riblets behind each juvenile peristome. Detached part ( “tuba ”) with fine, low ribs, and with short ribs around the umbilicus, not reaching the middle of the body whorl; this fine ribbing is recognisable a bit higher up, but gradually weakens towards penultimate whorl. Last ca. 0.25 whorls detached, detached part thick, aperture not or slightly protruding beyond spire-whorl plane; detached portion slopes downward at an angle of about 40°; upper suture continues on detached part as blunt, finely ribbed keel, and extends to back side of sinulus, bearing a shallow groove on inner side; this groove divides 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 without forming a keel, with a short, shallow groove on the umbilical side until a swelling that is situated behind and parallel with the peristome. Aperture axis slightly oblique to shell axis; aperture ovoid with a narrow, strongly isolated sinulus. Sinulus opens slightly upwards. Parieto-angular lamella very strongly developed, long, outer tip slightly protruding and slightly bent towards palatal lip, inner central portion of parieto-angular lamella slightly turns in the other (columellar) direction. Upper palatal tooth blunt, but strong, lower palatal tooth situated much deeper and lower in position, more pointed than upper palatal tooth. Columellar lamella denticle-like, not elongated, rather pointed, situated deep inside the aperture, its position corresponds with the end of the groove on the umbilical side of the tuba. Peristome thickened, strongly expanded (except for the sinulus area), its margin slightly reflected. Umbilicus closed.

Juvenile aperture. Juveniles of 3–4.5 whorls have four apertural barriers: parieto-angular lamella, upper palatal tooth, lower palatal tooth, columellar lamella. Their positions and morphology agree with that of other species of the D. cumingiana species group.

Measurements (in mm). SH = 3.55–3.88, SW = 1.3–1.39, AH = 0.75–0.8, AW = 0.76–0.78 (n = 3).

Etymology. This new species is dedicated to our good friend, the late Pongrat Dumrongrojwattana (1976–2023), who was an expert on microsnails.

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