Two new species of Tigriopus Norman, 1869 from Chonburi Province, Thailand (Crustacea: Copepoda: Harpacticidae) Author Chullasorn, Supawadee Author Kangtia, Pawana Department of Biology, Bansomdejchaopraya Rajabhat University, Bangkok 10600, Thailand. Author Song, Sung Joon 0000-0001-6177-2723 School of Earth and Environmental Sciences & Research Institute of Oceanography, Seoul National University, Seoul 08826, Korea. sungjoons @ gmail. com; https: // orcid. org / 0000 - 0001 - 6177 - 2723 sungjoons@gmail.com Author Khim, Jong Seong 0000-0001-7977-0929 School of Earth and Environmental Sciences & Research Institute of Oceanography, Seoul National University, Seoul 08826, Korea. sungjoons @ gmail. com; https: // orcid. org / 0000 - 0001 - 6177 - 2723 & jskocean @ snu. ac. kr; https: // orcid. org / 0000 - 0001 - 7977 - 0929 jskocean@snu.ac.kr text Zootaxa 2021 2021-10-12 5051 1 41 67 journal article 4068 10.11646/zootaxa.5051.1.6 0ecd8581-b443-4f28-8cd6-395ade9cb559 1175-5326 5564013 33238221-53F9-4842-8056-9536C09DD112 Key to species of the genus Tigriopus Norman, 1869 1. Antennary exp-2 with two setae............................................................ T. brachydactylus . - Antennary exp-2 with one seta...........................................................................2. 2. P4 exp-3 with two inner setae...........................................................................3. - P4 exp-3 with three inner setae..........................................................................7. 3. Male P2 enp-2 inner seta discrete at base.......................................................... T. japonicus . - Male P2 enp-2 inner seta fused to segment.................................................................4. 4. Anal operculum with fine hairs............................................................... T. californicus . - Anal operculum naked.................................................................................5. 5. Innermost seta of female P6 not extending to posterior margin of genital double-somite; mandible with 3-segmented exopod; exopod of maxillule with three setae......................................................................6. - Innermost seta of female P6 extending far beyond posterior margin of genital double-somite; mandible with 2-segmented exopod; exopod of maxillule with five setae............................................. T. wannapaensis sp. nov. - Innermost seta of female P6 extending far beyond posterior margin of genital double-somite; mandible with 3-segmented exopod; exopod of maxillule with three setae................................................... T. sirindhornae . 6. Female P6 with outermost plumose seta and two bare setae; maxillulary coxa with four setae....... T. namsaiensis sp. nov. Female P6 with middle plumose seta, one bare, and one pinnate seta; maxillulary coxa with three setae..... T. thailandensis . 7. Female P5 endopod with four setae.......................................................................8. Female P5 endopod with five setae......................................................................10. 8. Mandibular basis with one seta; maxillipedal claw prehensile and well-developed............................. T. raki . - Mandibular basis with two setae; maxillipedal claw reduced in length............................................9. 9. Male P5 endopod with one seta.................................................................. T. minutus . - Male P5 endopod unarmed.......................................................................... T. igai . 10. Knob on male P2 enp-2 outer margin present..............................................................11. - Knob on male P2 enp-2 outer margin absent...............................................................12. 11. Anal operculum with crenate margin; male P5 exopod with five setae.............................. T. kingsejongensis . - Anal operculum with many fine hairs; P5 exopod with four setae...................................... T. angulatus . 12. Mandible with 1-segmented exopod; crescent shape between 1 st and 2 nd innermost seta on female P5 exopod present.....13. - Mandible with 2-segmented exopod; crescent shape between 1 st and 2 nd innermost seta on female P5 exopod absent......14. TABLE 1. Morphological characters of the Tigriopus species recorded from Thailand.
T. namaiensis sp. nov. T. thailandensis T. wannapaensis sp. nov. T. sirindhornae
antennary coxa longer than in T. thailandensis small longer than in T. thailandensis longer than in T. thailandensis
antennary basis distal surface no ornamentation two setular rows no ornamentation one setular row
antenna exp-3 lateral seta discrete at base fused to segment fused to segment s discrete at base
mandibular praecoxa no ornamentation one setular row one setular row four setular rows
maxillulary coxal endite four setae three setae four setae five setae
P1 coxa no ornamentation one setular row no ornamentation no ornamentation
P2 & P4 basis one setular row no ornamentation no ornamentation no ornamentation
P6 ♀ armature outermost one plumose + two bare middle one plumose + two bare all setae plumose two plumose + one pinnate
P5 exp ♂: longest seta extending to end of 1st abdominal somite end of 2nd abdominal somite end of 2nd abdominal somite 2/3 of 3rd abdominal somite
P5 exp ♂: innermost seta extending to end of genital somite proximal 1/5 of 1st abdominal somite middle of 1st abdominal somite middle of genital somite
P5 exp ♂: length ratio of 1st innermost seta to 2nd one 3.1 2.1 2.2 2.0
P5 exp ♂: outermost seta plumose spinulose bipinnate smooth
13. Female P5 exopod reaching to distal margin of baseoendopod (with setules on inner margin), male antennary allobasis with tiny abexopodal seta......................................................................... T. kerguelenensis . - Female P5 exopod not reaching to distal margin of baseoendopod (without setules on inner margin), male antennary allobasis without abexopodal seta..................................................................... T. crozettensis . 14. Surfaces of antennary allobasis and P5 exopod in female with tuft of hairs.................................. T. fulvus . - Surfaces of antennary allobasis and P5 exopod in female without tuft of hairs............................ T. brevicornis .