Elaphoidella longiramus sp. nov. (Copepoda: Harpacticoida, Canthocamptidae), a new species of cave-dwelling copepod from central Thailand Author Watiroyram, Santi 0000-0003-4920-3979 Division of Biology, Faculty of Science, Nakhon Phanom University, Nakhon Phanom 48000, Thailand. santi. watiroyram @ npu. ac. th; https: // orcid. org / 0000 - 0003 - 4920 - 3979 santi.watiroyram@npu.ac.th Author Janpong, Wongduan 0000-0002-9401-8716 Applied Taxonomic Research Center, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand. wongduanjanpong @ gmail. com; https: // orcid. org / 0000 - 0002 - 9401 - 8716 & International College, Khon Kaen University, Khon Kaen 40002, Thailand. wongduanjanpong@gmail.com Author Sanoamuang, Laorsri 0000-0002-9401-8716 Applied Taxonomic Research Center, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand. wongduanjanpong @ gmail. com; https: // orcid. org / 0000 - 0002 - 9401 - 8716 & International College, Khon Kaen University, Khon Kaen 40002, Thailand. wongduanjanpong@gmail.com text Zootaxa 2022 2022-05-17 5138 2 152 166 journal article 55505 10.11646/zootaxa.5138.2.3 2c185b58-8f39-4c87-bfdd-97f375391682 1175-5326 6556819 C18EFDC5-AD6B-479D-AB4D-138BC6454E91 Key to the species of Elaphoidella from Thailand caves [Modified from Sanoamuang & Watiroyram (2021) ] Female : 1. Urosomites with smooth free posterior margins dorsally...................................................... 2 ― Urosomites with serrated free posterior margins dorsally...................................................... 3 2. P5 Exp with four setae................................................................... E. sanoamuangae ― P5 Exp with five setae...................................................................... E. jaesornensis 3. P5 Exp with four setae................................................................................. 4 ― P5 Exp with five setae................................................................................ 10 4. P4 Enp completely absent or with segmental vestige......................................................... 5 ― P4 Enp present....................................................................................... 6 5. P3 Enp-2 with one spine and one seta......................................................... E. thailandensis ― P3 Enp-2 with three setae............................................................. E. longiramus sp. nov. 6. P3 Enp-1 with inner seta............................................................................... 7 ― P3 Enp-1 without inner seta............................................................................ 8 7. P3 Enp-2 with three spines and setae......................................................... E. bromeliaecola ― P3 Enp-2 with six spines and setae............................................................ E. namnaoensis 8. P2 Enp-1 with inner seta........................................................................ E. ligorae ― P2 Enp-1 without inner seta............................................................................ 9 9. P4 Enp-2 with three spines and setae............................................................. E. brancelji ― P4 Enp-2 with four spines and setae............................................................. E. paraaffinis 10. Posterior margin of urosomites finely serrated............................................................. 11 ― Posterior margin of urosomites coarsely serrated.............................................. E. bidens decorata 11. Caudal ramus without spinules at distal inner margin............................................... E. intermedia ― Caudal ramus with spinules at distal inner margin..................................................... E. isana Male (unknown for E. bidens decorata , E. isana , E. jaesornensis , and E. namnaoensis ): 1. Urosomites with smooth free posterior margins dorsally........................................ E. sanoamuangae ― Urosomites with serrated free posterior margins dorsally...................................................... 2 2. P4 Enp completely absent or with segmental vestige......................................................... 3 ― P4 Enp present...................................................................................... .. 4 3. P2 Enp-2 with two setae................................................................... E. thailandensis ― P2 Enp-2 with one seta.............................................................. E. longiramus sp. nov. 4. P2 Enp-1 without inner seta............................................................................ 5 ― P2 Enp-1 with inner seta............................................................................... .. 6 5. P2 Enp-2 with three spines and setae............................................................. E. brancelji ― P2 Enp-2 with four spines and setae............................................................ E. paraaffinis 6. P4 Exp-3 with transformed spine........................................................................ 7 ― P4 Exp-3 without transformed spine............................................................... E. ligorae 7. Transformed spine of P4 Exp-3 presented with reduced spine........................................ E. intermedia ― Transfromed spine of P4 Exp-3 presented with antler-like spine..................................... E. bromeliacola