Sinoennea panhai Páll-Gergely & Hunyadi, 2020

Páll-Gergely, Barna, Reischütz, Alexander, Maassen, Wim J. M., Grego, Jozef & Hunyadi, András, 2020, New taxa of Diapheridae Panha & Naggs in Sutcharit et al., 2010 from Laos and Thailand (Gastropoda: Eupulmonata: Stylommatophora), Raffles Bulletin of Zoology 68, pp. 1-13 : 7-9

Sinoennea panhai Páll-Gergely & Hunyadi , new species

( Figs. 4 C–E, 6G)

Type material. Holotype (1 shell, H: 3.84 mm, D: 1.63 mm; Fig. 4E ) ( HNHM 103487 ), Thailand, Chiang Rai Province, Doi Tung, near the parking lot 50 m from Wat Phra That Doi Tung , 1,350 m a.s.l., 20°19.540′N, 99°49.987′E, locality code: 2015/17, coll. A. Hunyadi, 12 February 2015; 1 figured paratype ( HNHM 103488 ; Fig. 4D ), same data as holotype; 2 paratypes ( CUMZ 5135 ), same data as holotype; 13 paratypes ( HA/13 ), same data as holotype.

Other material. 1 figured juvenile shell ( HNHM 103489 ; Fig. 4C ), same data as holotype ; 7 juvenile shells ( HA/7 ), same data as holotype .

Diagnosis. A medium-sized species with glossy but ribbed, elongate-ovoid shell, ovoid aperture, strongly bent parietal lamella, and closed umbilicus.

Description. Shell yellowish to very light greyish, somewhat translucent. Shell elongate-ovoid with cylindrical last three whorls. Entire shell with 6.5–7 whorls. Protoconch consisting of two whorls, glossy, with some signs of fine wrinkles near suture. Upper whorl overall glossy, with rather regular, strong but low ribs. Individual ribs look like wrinkles (or waves) created by pushing the shell surface in upper (towards protoconch) direction. Ribs become less regular on last two whorls, occasionally appearing only below suture, reappearing as prominent regular ribs on last quarter whorl. Whorls moderately bulging, suture not very deep. Aperture suboval, somewhat quadrangular. Parietal callus rounded, does not reach half of preceding whorl, relatively thick, only slightly “smeared” onto preceding whorl. Apertural dentition four or five-fold. Parietal lamella strongly developed, outer portion strongly bent in direction of columella, then inner part abruptly turns in other direction. Sinulus relatively narrow, rounded, well isolated. Tips of parietal lamella and upper lablar denticle situated close to each other. Palatal wall with an upper and a lower denticle of comparable size, both strong, not elongated, lower one situated much deeper than upper one. Columellar tooth deeply situated, lamella-like, long, sharp, vertical, and parallel with shell axis. A blunt, inconspicuous thickening on the columellar lip is sometimes present. Peristome strongly thickened and expanded, not reflected. Basal swelling very slight, situated relatively far from peristome. Depression anterior to basal swelling on the outer side deep, slightly elongate, corresponding with inner palatal denticle. There is also a slight depression on the inner side as well. Umbilicus entirely closed.

Measurements. H = 3.84–4.08 mm, D = 1.59–1.68 mm (smallest and largest specimens measured).

Differential diagnosis. Sinoennea panhai , new species, can be distinguished from Sinoennea reischuetzorum Maassen, 2016 , by a smaller, ovate shell and a more rounded and less protruded aperture. Sinoennea prima Panha & J. B. Burch, 1999 , has a more cylindrical, regularly ribbed shell with a weaker parietal lamella.

Etymology. The species is dedicated to Prof. Somsak Panha (Chulalongkorn University, Thailand) to acknowledge his work, which resulted in the discovery of numerous new invertebrate species in Southeast Asia and initiated the career of many young taxonomists.

Figures

Fig. 4. New Sinoennea Kobelt, 1904, species from Thailand. A, holotype of Sinoennea sutchariti Páll-Gergely & Hunyadi, new species; B, subadult paratype of S. sutchariti, new species; C, juvenile shell (not paratype) of Sinoennea panhai Páll-Gergely & Hunyadi, new species; D, aperture of a paratype of S. panhai; E, holotype of S. panhai. Scale bar represents 1 mm.