Cirolana, Leach, 1818

Rodcharoen, Eknarin & Bruce, Niel L., 2021, Two new species of the marine isopod genus Cirolana Leach, 1818 (Crustacea Isopoda: Cirolanidae) from the coast of the western Gulf of Thailand, Zootaxa 4950 (3), pp. 469-486 : 485

Key to the species of Cirolana ‘pleonastica- group ’ in the South-East Asia region

1 Body dorsal surfaces without nodules or tubercles on posterior margin of pereonites and pleonites............................................................................................. C. tuberculata ( Richardson, 1910)

- Body dorsal surfaces with or without nodolsoes on posterior margin of pereonites, but with tubercles on pleonites........ 2

2 Body dorsal surfaces without nodules on posterior margin of pereonites 6 and 7................................... 3

- Body dorsal surfaces with nodules on posterior margin of pereonites 6 or 7....................................... 4

3 Head anteriorly produced and overriding the antennular bases; posterior of pleotelson (in male) with 2 tubercles and scattered nodules................................................................. C. trulla Sidabalok & Bruce, 2018

- Head anteriorly not produced and overriding the antennular bases; pleotelson with a median row of fine setae................................................................................. C. lembeh Sidabalok & Bruce, 2018

4 Uropod not sexually dimorphic, male uropodal exopod dorsal posterior surface without distolateral stiff setae........... 5

- Uropod sexually dimorphic, male uropodal exopod dorsal posterior surface with distolateral stiff setae................. 7

5 Antennula peduncle with 4 unfused articles; lateral margin of uropodal exopod having continuous row of plumose setae..................................................................................... C. khamensis sp. nov.

- Antennula peduncle with articles 1 and 2 fused; lateral margin of uropodal exopod having discontinuous of plumose setae.. ................................................................................................... 6

6 Body dorsal with nodules on posterior of both pereonites 6 and 7; frontal lamina pentagonal, lateral margins anteriorly concave................................................................. C. merlion Sidabalok & Bruce, 2018

- Body dorsal with nodules on posterior of pereonite 7 only; frontal lamina pentagonal, lateral margins anteriorly straight....................................................................... C. phuketensis Rodcharoen et al., 2017

7 Pereonites 2–3 without transverse impressed line; pleonite 3 without median tubercle, pleonite 4 with median tubercle and 4 indistinct sublateral tubercules on each side (set as one row)................................. C. parawongat sp. nov.

- Pereonites 2–3 with each a single transverse impressed line; pleonite 3 and 4 with 1 median tubercle (the largest) and 10 sublateral tubercles on each side (set as two row).................................. C. fasfes Sidabalok & Bruce, 2018