The millipede genus Orthomorpha Bollman, 1893 in Thailand. 1. Revision of the sericata - group, with descriptions of four new species (Diplopoda, Polydesmida, Paradoxosomatidae) Author Likhitrakarn, Natdanai Author Golovatch, Sergei I. Author Panha, Somsak text Zootaxa 2010 2361 23 45 journal article 10.5281/zenodo.193638 3d92ba7f-39cc-4001-a032-50ab73547f09 1175-5326 193638 Key to species of the sericata -group 1. At least surface of metaterga leathery, dull.................................................................................................................. 2. - Dorsal surface shining ................................................................................................................................................ 4. 2. Only caudal parts of paraterga contrastingly light ( Figs 14 A–G, J–L). Paraterga less strongly developed, narrower, with only a small incision at best in front 1/3 extent ( Figs 14 A, C, E, J & L). No tergal setae borne on evident knobs/ tubercles ....................................................................................................................................................... O. sericata - Entire paraterga contrastingly light, much broader, largely with an evident, dentiform incision in front 1/3 extent ( Figs 1 B, D & K, 7B & D). At least some tergal setae borne on evident knobs/tubercles .......................................... 3. 3. Surface of metaterga rough, microgranulate and rugulose ( Figs 1 B–H, K–M). Metatergal setigerous tubercles higher, present also on collum. Paratergal incisions especially prominent ( Figs 1 B–E, K & L). ....... O. enghoffi sp. n. - Surface of metaterga nearly smooth, microgranulate ( Figs 7 B–H). Metatergal setigerous tubercles evidently smaller, absent from collum. Paratergal incisions evident, but not so prominent ( Figs 7 B & D) .................... O. alutaria sp. n. 4. Adults> 30 mm long and> 4 mm wide. Collum broadly rounded laterally ( Figs 12 B & C). Paraterga set high, at least some upturned above dorsum. Sternal cones between male coxae 4 isolated ( Figs 12 I & J). ............................... ..................................................................................................................................................... O. parasericata sp. n. - Adults < 30 mm long and < 4 mm wide. Collum narrowly rounded to angulate laterally ( Figs 5 B &C, 9B & C). Paraterga set high, but remaining below dorsum even in male. Sternal cones between male coxae 4 fused basally into a single lamina ( Figs 5 I & J, 9I & J)............................................................................................................................ 5. 5. Bases of paraterga more broadly light ( Figs 5 A–H). Legs shorter, about 1.2 (male) or 1.0 times (female) as long as midbody height. Tip of solenophore like an elongate and undulate lobe ( Figs 3 C & D, 6) ................... O. subsericata - Bases of paraterga more narrowly light ( Figs 9 A–H). Legs longer, about 1.5 (male) or 1.2–1.3 times (female) as long as midbody height. Tip of solenophore tridentate ( Figs 10 , 11 A & B). .............................................. O. asticta sp. n.