The giant pill-millipede genus Zephronia Gray, 1832 from Thailand, with a redescription of Z. siamensis Hirst, 1907 and descriptions of three new species (Diplopoda, Sphaerotheriida, Zephroniidae) Author Srisonchai, Ruttapon https://orcid.org/0000-0002-7142-0999 Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand Author Sutcharit, Chirasak Animal Systematics Research Unit, Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand Author Likhitrakarn, Natdanai Division of Plant Protection, Faculty of Agricultural Production, Maejo University, Chiang Mai, 50290, Thailand & Biodiversity and Utilization Research Center of Maejo University, Maejo University, Chiang Mai, 50290, Thailand kongerrrr@hotmail.com text ZooKeys 2021 2021-10-29 1067 19 56 http://dx.doi.org/10.3897/zookeys.1067.72369 journal article http://dx.doi.org/10.3897/zookeys.1067.72369 1313-2970-1067-19 AEAF44EE2CCD4E319CBCA4C5ACB0E2EB 34D3B870A92C50819DE85FF5DDE19A1D Zephronia phrain Likhitrakarn & Golovatch, 2021 Figures 1E, F ; 5 ; 6 Zephronia phrain Likhitrakarn & Golovatch, 2021 in Likhitrakarn et al. 2021 : 19. Material examined. Thailand - Tak Province • 2 ♂♂ 2 ♀♀ ; Mae Sot District , Phawor Shrine ; 16°46'16.8"N , 98°41'13"E ; 694 m a.s.l. ; October 2016 ; S. Panha , R. Srisonchai , C. Sutcharit , W. Siriwut leg. Description of some characters for a population in Tak Province. Body length : Length in male 29.0-31.0 mm (holotype 33.5 mm), female 30.0-33.0 mm; head 5.5 mm; thoracic shield 5.5-6.0 mm; anal shield 9.5-10.5 mm. Body width : Width in male 16.5 mm (holotype 18.2 mm), female 16.5-17.0 mm; head 8.0-9.0 mm; thoracic shield 15.0-16.0 mm; anal shield 14.0-15.5 mm. Body height : Height in male 10.0 mm (holotype 11.2 mm), female 10.0-11.0 mm; thoracic shield 9.0-10.5 mm; tergite 9.5-11.0 mm. Color (Fig. 1E, F ): Specimens in life with brown or dark brown; head, antennae and collum, thoracic shield, paratergites, anal shield and legs brown or dark brown; anterior margins of thoracic shield, of tergites and of anal shield dark brown contrasting with the posterior brown ones; setose part of thoracic shield with golden sheen. Color in alcohol after six years not changed. Tergites (Fig. 1E, F ): Quite shiny; surface glabrous, with sparse, tiny, inconspicuous pits; tip of paratergite of midbody tergites curved, directed posteroventrad; anterior half of lateral margin covered with long and conspicuous setae. Legs (Fig. 5B ): Leg-pairs 1 and 2 without apical spine. Leg-pair 1 with four ventral spines, leg-pair 2 with four or five ventral spines. Leg-pair 3 with seven or eight ventral spines and one or two apical spines. Leg-pair 4 with nine or ten ventral spines and two or three apical spines. Leg-pairs 5-19 with 9-11 ventral spines and 1-3 apical spines. Last two leg-pairs with eight or nine ventral spines, and one or two apical spines. In leg 9, femur ca. 1.7 x , tarsus ca. 3.4 x longer than wide. Length of tarsus> femur> prefemur> coxa> tibia ≥ postfemur. All podomeres densely setose. Coxa large, with dentate ridge marginally (coxal process). Coxal process absent in leg-pairs 1 and 2. Prefemur without teeth. Femur slightly extended mesally; mesal margin with very small, tiny, inconspicuous teeth. Subanal plate (Fig. 5F ): Trapeziform, undivided; central margin (tip) truncate, narrow; lateral margin straight. Densely setose. Head, antenna, Toemoesvary's organ, gnathochilarium, stigmatic plates, laterotergites, collum, thoracic shield, endotergum, anal shield, male sexual characters, anterior telopods, posterior telopods, and female sexual characters: Same as the original description in Likhitrakarn et al. 2021 . Distribution and habitats (Figs 15D , 16 ). Currently known to occur in northern Thailand (Chiang Mai and Tak provinces) in dry dipterocarp forest and from limestone areas. Observations made at Phawor Shrine found that most specimens were seen creeping on rocks, with some hiding in leaf litter. Notably, the specimens were found in syntopy with the dragon millipede ( Nagaxytes spatula Srisonchai, Enghoff & Panha, 2018) at the same site ( Srisonchai et al. 2018b ). Remarks. Based on observations of live specimens in the field, two color patterns were found, dark green in type specimens and brown/dark brown in the others from Tak Province (Fig. 2E, F ; fig. 1C, D in Likhitrakarn et al. 2021 ). A species described by Pocock (1890) from Myanmar ( Thagata , Mount Mooleyit, Kayah State), Z. gestri Pocock, 1890 occurs close to the type locality of this widespread species, but Z. phrain clearly differs from Z. gestri by being longer in body length (vs. shorter, ca. 14 mm), having a longer immovable finger or longer process of telopoditomere 2 (vs. shorter) and having a truncate/round central margin of subanal plate (vs. convex). Based on material described by Likhitrakarn et al. 2021 , deposited in the CUMZ (holotype CUMZ-Zeph0003, paratypes CUMZ-Zeph0004).