A new species of Rangabradya (Copepoda, Harpacticoida, Ectinosomatidae) from a cave in Satun Province, southern Thailand Author Boonyanusith, Chaichat https://orcid.org/0000-0003-1487-2160 School of Biology, Faculty of Science and Technology, Nakhon Ratchasima Rajabhat University, Nakhon Ratchasima 30000, Thailand chaichat.b@nrru.ac.th Author Athibai, Sujeephon Applied Taxonomic Research Center and Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand text ZooKeys 2021 2021-01-04 1009 45 66 http://dx.doi.org/10.3897/zookeys.1009.54554 journal article http://dx.doi.org/10.3897/zookeys.1009.54554 1313-2970-1009-45 5400526C94CA4E73B73857427B8635DD CEF3396D7E5C5359BFD6D69F64AB55DF Subgenus Siamorangabradya subgen. nov. Diagnosis. Ectinosomatidae , with fusiform habitus. Urosomite with spinule ornamentation. Antennule six-segmented in both male and female; third segment longest. Distal segment of antennary Exp elongate, with two apical setae; longest seta normally developed; shortest one as long as segment bearing it. Mandible with additional spine at dorsal site of pars incisiva. Coxa of maxillule free. Maxilla straight, with three setae on distal endite of syncoxa and allobasis with two medial setae. Maxilliped three-segmented, with four setae on Endp. Armature formula of Exp-3, from P1-P4: 5.6.6.6. Female P5Exp partly fused with baseoendopod, with three marginal setae; endopodal lobe of baseoendopod with two apical elements. Female P6 reduced to small protuberance with one apical seta on peduncle. Male P5Exp completely fused to baseoendopod, with two apical setae on endopodal lobe. Male P6 reduced to simple plate and unarmed. Type species. Rangabradya (Siamorangabradya) wongkamhaengae subgen. et sp. nov. Etymology. The subgenus is named after Siam, Thailand's former name, prefixed to the existing generic name Rangabradya . The name is a feminine noun in the nominative singular.