Notes on the hypselostomatid snails (Gastropoda: Heterobranchia) from limestone hills in Western Cambodia with a new record and a new species Author Sutcharit, Chirasak Author Ngor, Peng Bun Author Páll-Gergely, Barna Author Jeratthitikul, Ekgachai Author Siriwut, Warut Author Srisonchai, Ruttapon Author Ng, Ting Hui Author Jirapatrasilp, Parin Author Panha, Somsak text Journal of Natural History 2023 2023-09-27 57 25 - 28 1287 1303 http://dx.doi.org/10.1080/00222933.2023.2223386 journal article 273183 10.1080/00222933.2023.2223386 5cd7307d-1cec-4f08-8965-9c8e1ca2f625 1464-5262 10015601 Gyliotrachela torticollis Benthem Jutting, 1962 ( Figures 1 , 3 ; Table 1 ) Gyliotrachela torticollis Benthem Jutting, 1962: 8–10 , fig. 4. Type locality: Phum Troung Mean , 15 km south-west of Battambang , Cambodia [Phnom Troung Mean] . Material examined CAMBODIA : Paratype RMNH-ZMA 137136 (3 shells; Figure 3 (a)) from Phuom Troung Mean , 15 km SW of Battambang . CUMZ 14204 (33 shells; Figure 3 (b, c)) from Phnom Sampeov Mountain , Banan District , Battambang Province ( 13.026000°N , 103.101011°E ) . CUMZ 14205 (113 shells) from Cave at Phnom Banan Temple , Banan District , Battambang Province ( 12.951464°N , 103.143903°E ) . Diagnosis Shell depressed heliciform, and long and descending tuba. Protoconch sculptured with only shallow pits; teleoconch with spiral striation. Apertural dentition with five major lamellae (parietal, angular, upper and lower palatals, basal, and columellar), and numerous plicae. All lamellae and plicae spinose. Description Shell depressed heliciform, last whorl enlarged with descending tuba, and spire elevated and conical. Shell colour brownish, 3.0– 3.2 mm in length, 3.1–3.3 mm in width, and with 4–4½ whorls. Protoconch about two whorls and sculptured with roundish and shallow pits. Teleoconch with irregularly strong or weak growth lines, and malleations or wrinkles arranged on thin spiral striations. Spire raised, whorl rounded and evenly sloped, and impressed suture. Last whorl shouldered, little concaved periphery, and long tuba projecting anteriorly downward. Two wide and shallow furrows present, one on upper periphery, and one surrounding umbilicus and extended to expanded lip. Aperture irregularly circular; peristome free with broadly expanded lip margins. Apertural dentition with five prominent lamellae: parietal, angular, upper and lower palatals, and columellar. Parietal (p) and angular (a) lamellae very close together; parietal tall; angular shorter than parietal and situated anteriorly to peristome. Palatal wall with strong upper (upl) and lower palatal (lpl) lamellae, three small suprapalatal plicae, one or two interpalatal plicae, and one small and one tiny infrapalatal plicae. Columella area with strong columellar (c) lamella, two tiny subcolumellar plicae, and three small supracolumellar plicae. All apertural dentition (lamellae and plicae) with small spines along approximately central line of lamellae. Umbilicus very wide and showing nearly all preceding whorls. Figure 3. Gyliotrachela torticollis . (a) Paratype ZMA 137136 from Phuom Troung Mean, Cambodia, with apertural dentition. (b, c) Specimen CUMZ 14204 from Phnom Sampov, Battambang, (b) shell with apertural dentition arrangement with its surface sculpture, and (c) protoconch sculpture. Abbreviations: a = angular lamella, b = basal lamella, c = columellar lamella, lpl = lower palatal lamella, p = parietal lamella, upl = upper palatal lamella. Distribution It is known from multiple limestone outcrops in Battambang Province , Cambodia ( Figure 1 ). The collection locality in Phnom Sampeov is about 1.8 km east of the Phnom Troung Mean, the original type locality of this species ( Benthem Jutting 1962 ). Snails live on the limestone wall, in rock crevices, and near the cave entrance. Differential diagnosis Gyliotrachela torticollis is superficially similar to H. srakeoensis , but it differs by having thin spiral striations on the last whorl and angular lamella present, while H. srakeoensis has only a wrinkled shell surface without spiral striations, and angular lamella is absent. This species differs from A. chaunosalpinx from southern Cambodia in having a depressed heliciform shell, lower conical spire, descending tuba, distinctly shouldered last whorl, angular lamella present, and no hook-shaped lamella in the aperture. In comparison, A. chaunosalpinx possesses a turreted heliciform shell, elevated spire, little descending tuba, angular last whorl, without angular lamella, and with hook-shaped lamella in the aperture ( Vermeulen et al . 2019b ). Remark This species is probably endemic to Battambang Province , Cambodia .