Gyliotrachela hungerfordiana (von Moellendorff , 1891)

Tongkerd, Piyoros, Lwin, Ngwe, Pall-Gergely, Barna, Chanabun, Ratmanee, Pholyotha, Arthit, Prasankok, Pongpun, Seesamut, Teerapong, Siriwut, Warut, Srisonchai, Ruttapon, Sutcharit, Chirasak & Panha, Somsak, 2024, Contributions of a small collection of terrestrial microsnails (Pupilloidea, Hypselostomatidae) from Myanmar with description of three new species, ZooKeys 1195, pp. 157-197 : 157

Gyliotrachela hungerfordiana (von Moellendorff, 1891)

Fig. 10 , 13M

Hypselostoma hungerfordianum von Möllendorff, 1891: 337, 338, pl. 30, fig. 7, 7a. Type locality: Bukit Pondong [Gunung Pondok, Padang Rengas, Perak, Malaysia]. Sykes 1902: 61.

Gyliauchen hungerfordianus . Pilsbry 1917: 212, pl. 36, figs 1-4.

Gyliotrachela hungerfordiana . Laidlaw 1933: 214. van Benthem Jutting 1949: 60. van Benthem Jutting 1950: 26. Zilch 1959: 164, fig. 563. van Benthem Jutting 1960: 14. Berry 1961: 101. Berry 1966: 12. Zilch 1984: 166, pl. 2, fig. 19. Davison 1995: 239. Schileyko 1998: 141, fig. 162. Schilthuizen et al. 1999: 283. Foon et al. 2017: 79, fig. 30b.

Gyliotrachela khaochongensis Panha, 1998: 53-56, fig. 2. Type locality: Khaochong Wildlife Sanctuary, Trang Province, Thailand. Panha and Burch 2005: 70, 71, fig. 61. syn. nov.

Gyliotrachela phoca Tongkerd & Panha in Tongkerd et al. 2013: 71-75, figs 5-7. Type locality: Bat cave near Klong Chak Waterfall, Lanta Yai Island, Lanta Islands National Park, Krabi Province, Thailand. syn. nov.

Material examined.

Khaochong Wildlife Sanctuary, Trang Province, Thailand: Paratype CUMZ [CUIZM] Ver 011 (Fig. 10B ). Bukit Pondok , Perak, Malaysia: NHMUK collection (2 shells: Figs 10A , 13M ). Buddha Cave , Lenya city, Tanintharyi Region, Myanmar (locality code TN1; 11°13'46.2"N, 99°10'34.3"E): CUMZ 14382 (1 shell; Fig. 10C ); CUMZ 14406 (61 shells); CUMZ 14407 (12 shells; measured) .

Description.

Shell concave-conical, pale yellowish to brown in colour, moderate spire and 4- 4½ widely convex whorls. Shell height 1.6-1.9 mm and shell width (including tuba) 2.5-2.9 mm. Apex blunt; protoconch ~ 1¾ whorls with wrinkled roundish pits. Teleoconch generally with very fine irregular growth lines and wrinkles; suture shallow. Last whorl angular with a prominent central keel with grooves above and below the keel. Tuba long and ~ 8-10 degrees angled upward compared to the shell axis. Peristome widely expanded; lip whitish to yellowish. Aperture roundly rectangular; aperture with many barriers. Parietal lamella large, strong, blunt, and located slightly deep inside aperture. Two small and weak infraparietal lamellae present. Angular lamella small, short, and reaching peristome. Upper palatal plica of approximately same size as angular lamella; very small suprapalatal plicae sometimes present. Lower palatal lamella tall and strong; very low and weak interpalatal plicae and infrapalatal plicae generally present. Columellar lamella strong and distinct; very low and weak supracolumellar and subcolumellar lamellae present. All dentitions generally covered with very fine spines on surface. Umbilicus widely perforate, ~ 1/3 of shell width, rounded, deep, and surrounded by blunt periumbilical keel.

Distribution.

This species has a wide distribution from southern Myanmar to southern Thailand and Peninsular Malaysia. Originally it was described from Perak and then subsequently reported from several localities in Peninsular Malaysia: Perlis, Pahang, Kelantan, Kedah, and Selangor states ( von Möllendorff 1891; van Benthem Jutting 1949, 1950, 1960; Foon et al. 2017). This species was also reported in southern Thailand: Trang, Suratthani, Krabi, Patthalung, Songkla, and Satul provinces ( Panha 1998; Panha and Burch 2005; Tongkerd et al. 2013). In Myanmar, this species recorded is known only from an isolated limestone karst in the Tanintharyi Region.

Differential diagnosis.

Gyliotrachela hungerfordiana differs from all other known Gyliotrachela species from Myanmar in having a thin shell, long and slender tuba, tall spire, and strong and curved keel on periphery. In contrast, G. bensonianum has a conical spire, short tuba, curved keel on last whorl, and apertural dentition without supra- and inter- palatal plicae or supra- and sub- columellar lamellae; G. tianxingqiaoensis and G. muangon possess angular last whorl, short tuba nearly adnate to last whorl, and with many small accessory plicae and lamellae ( Gojšina et al. 2022).

Remarks.

Gyliotrachela khaochongensis and G. phoca were described from southern Thailand; the type specimens look identical to the type and topotypic specimens of G. hungerfordiana in shell form, shell sculpture and apertural dentitions ( Panha 1998; Tongkerd et al. 2013), with no significant differences. Therefore, they are considered here as junior synonyms of G. hungerfordiana .

Figures

Figure 10. Gyliotrachela hungerfordiana A topotype specimen NHMUK collection from Perak, Malaysia B paratype CUIZM, Ver 011 of G. khaochongensis, from Trang Province, Thailand C specimen CUMZ 14382 from Tanintharyi Region, Myanmar. Abbreviations: a: angular lamella, c: columellar lamella, ip: infraparietal lamella, itpl: interpalatal plica, ifpl: infrapalatal plica, lpl: lower palatal plica, p: parietal lamella, sbc: subcolumellar lamella, spc: supracolumellar lamella, sppl: suprapalatal lamella, upl: upper palatal plica.

Figure 13. Synoptic view of representatives of hypselostomatid snails recorded from Myanmar A Acinolaemus dayanum, specimen HA Collection B Acinolaemus cryptidentatus, specimen CUMZ 14413 C Anauchen eotvosi, holotype NHMUK 1903.7.1.1227.1 (after Pall-Gergely 2023 a: fig. 1 c) D Angustopila occidentalis, holotype HNHM 103483 (after Pall-Gergely et al. 2023: fig. 70 a) E Angustopila elevata, specimen HNHM 103484 (after Pall-Gergely et al. 2023: fig. 13 a) F Bensonella salwiniana, specimen CUMZ 14393 G Bensonella anguloobtusa, specimen CUMZ 14400 H Bensonella taiyaiorum sp. nov., paratype CUMZ 14403 I Bensonella lophiodera sp. nov., paratype CUMZ 14405 J Clostophis sankeyi, holotype UMZC I. 103320 (after Preece et al. 2022: fig. 70 e) K Clostophis thinbowguensis, holotype MNHN-IM- 2000 - 38057 (after Pall-Gergely et al. 2022: fig. 9 c) L Gyliotrachela bensonianum, syntype NHMUK 20191141 (after Gojsina et al. 2022: fig. 4 a) M Gyliotrachela hungerfordiana, specimen NHMUK collection from Perak, Malaysia N Gyliotrachela tianxingqiaoensis, holotype IZCAS TM 025075 (after Gojsina et al. 2022: fig. 3 a) O Gyliotrachela muangon, specimen CUMZ 14410 P Gyliotrachela aunglini sp. nov., paratype CUMZ 14412 Q Hypselostoma tubiferum, specimen NHMUK 1888.12.4.17 - 22 ex. Theobald collection from Tonduong, Burma.