Contributions of a small collection of terrestrial microsnails (Pupilloidea, Hypselostomatidae) from Myanmar with description of three new species Author Tongkerd, Piyoros https://orcid.org/0000-0001-9221-9293 Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand Author Lwin, Ngwe https://orcid.org/0000-0002-4394-3741 Fauna and Flora International, No. 35, 3 rd Floor, Shan Gone Condo, Myay Ni Gone Market Street, Sanchaung Township, Yangon, Myanmar Author Pall-Gergely, Barna https://orcid.org/0000-0002-6167-7221 Plant Protection Institute, Centre for Agricultural Research, ELKH, Herman Otto ut 15, 1022 Budapest, Hungary Author Chanabun, Ratmanee https://orcid.org/0000-0003-4584-2773 Program in Animal Science, Faculty of Agricultural Technology, Sakon Nakhon Rajabhat University, Sakon Nakhon 47000, Thailand Author Pholyotha, Arthit https://orcid.org/0000-0001-6677-1164 Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand Author Prasankok, Pongpun https://orcid.org/0000-0001-5967-223X Biodiversity and Utilization Research Unit, Center of Excellence in Modern Agriculture, Sakon Nakhon Rajabhat University, Sakon Nakhon 47000, Thailand Author Seesamut, Teerapong https://orcid.org/0009-0003-9589-8641 School of Biology, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand Author Siriwut, Warut https://orcid.org/0000-0001-6760-9724 Department of Biology, Faculty of Science, Rangsit University, Pathum Thani 12000, Thailand Author Srisonchai, Ruttapon https://orcid.org/0000-0002-7142-0999 Animal Systematics and Molecular Ecology Laboratory, Department of Biology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand Author Sutcharit, Chirasak https://orcid.org/0000-0001-7670-9540 Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand jirasak4@yahoo.com Author Panha, Somsak https://orcid.org/0000-0002-4431-2458 Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand & Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand somsak.pan@chula.ac.th text ZooKeys 2024 2024-03-14 1195 157 197 http://dx.doi.org/10.3897/zookeys.1195.112112 journal article http://dx.doi.org/10.3897/zookeys.1195.112112 1313-2970-1195-157 7CFF082DDA924ECF8E7C0A9972F6CD08 E26F0ADE4B4C5BCB943E2FCC63E349C4 Gyliotrachela muangon Panha & Burch, 2004 Figs 11 , 13O Gyliotrachela muangon Panha & Burch in Panha et al. 2004 : 67, 68, fig. 7. Type locality. Muangon Cave, San Kam Pang District, Chiangmai Province, Thailand. Panha and Burch 2005 : 76, 77, fig. 66. Gojsina et al. 2022 : 138, fig. 6. Material examined. Yum Cave , Kalaw City , Shan State , Myanmar (locality code KW1; 20°37'18.1"N , 96°29'8.3"E ; 854 m a.s.l. ): CUMZ 14385 (1 shell; Fig. 11A, B ); CUMZ 14408 (6 shells); CUMZ 14409 (12 shells; measured); CUMZ 14410 (2 shells; Figs 11C , 13O ) . Figure 11. Gyliotrachela muangon from Kalaw City, Shan State A, B specimen CUMZ 14385 from Kalaw City, Shan State , ( A ) shell and ( B ) protoconch C specimen CUMZ 14410 from Kalaw City, Shan State . 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. Description. Shell broadly ovate-conical, reddish brown in colour, moderate spire, and 43/4 -5 widely convex whorls. Shell height 1.8-2.0 mm and shell width (including tuba) 2.5-2.9 mm. Appex blunt; protoconch 13/4 whorls, wrinkled with roundish pits. Teleoconch with wrinkles and irregular growth lines crossed by conspicuous spiral ridges throughout; suture well impressed and deep. Last whorl widely angular, tuba short and ~ 10-12 degrees angled upward. Peristome widely expanded; lip reddish brown. Aperture roundly triangular and many aperture dentitions. Parietal lamella large, tall, strong, blunt and slightly deep inside aperture. One or two minute infraparietal lamellae may be present. Angular lamella strong and reaching peristome. Upper palatal plica strong; sometimes very small suprapalatal plicae present. Lower palatal plica tall and strong; one or two small interpalatal plicae and infrapalatal plicae usually present. Columellar lamella very strong, distinct and horizontal; very low and weak supracolumellar and subcolumellar lamellae present. All dentitions generally with very fine spines on surface. Umbilicus perforate, ~ 1/4 of shell width, rounded, deep, and surrounded by blunt periumbilical keel. Distribution. This species was originally described from Chiangmai Province, northern Thailand ( Panha et al. 2004 ). Later, a few specimens were collected from Hsi Hseng Township, Taunggyi District, Shan State ( Gojsina et al. 2022 ). Recently, several specimens were collected from Kalaw Township, Taunggyi District, Shan State. Differential diagnosis. Gyliotrachela muangon can be distinguished from G. tianxingqiaoensis from China and Myanmar, and G. plesiolopa Inkhavilay & Panha, 2016 from Laos by having weak spiral striae, five strong major lamellae and plicae (parietal, angular, columellar, and upper and lower palatals). In contrast, G. tianxingqiaoensis lacks spiral striation on the teleoconch, has a more elevated aperture, a narrower umbilicus and has more numerous teeth in the aperture; G. plesiolopa has a more expanded peristome, and a slightly weaker peripheral keel, which is also less upturned and flatter on the lower side ( Inkhavilay et al. 2016 ; Gojsina et al. 2022 ). The three species from Thailand ( G. saraburiensis Panha & Burch in Burch et al. 2003 , G. muangon and G. cultura Tanmuangpak & Dumrongrojwattana, 2022) are very similar to G. muangon in the turbinate shell form, the short and slightly descending tuba, the weakly angulated last whorl, the spiral striae on the teleoconch, and by having five major apertural dentitions. The significant distinction among them is mainly the number of accessory plicae and lamellae. Specifically, G. muangon possesses two infraparietals, two interpalatal and two infrapalatals, while G. saraburiensis has three infraparietals, three interpalatals and five infrapalatals, and G. cultura exhibits one infraparietal, one interpalatal and two infrapalatals ( Burch et al. 2003 ; Panha et al. 2004 ; Panha and Burch 2005 ; Tanmuangpak and Dumrongrojwattana 2022 ). Remarks. The examined specimens from Myanmar show minor variability in terms of apertural dentition from the type specimen from Thailand. Two interpalatal plicae are observed in the Myanmar specimens, while the type specimen has only one interpalatal plica.