Cirolana, Leach, 1818

Bruce, Niel L., 2017, Review of the species of the Cirolana ‘ parva - group’ (Cirolanidae: Isopoda: Crustacea) in Indonesian and Singaporean waters, Zootaxa 4317 (3), pp. 401-435 : 403

Key to the males of Cirolana ‘ parva -group’ in Indonesia and Singapore

Females often cannot be identified without the presence of the males.

1. Antennula peduncle articles 1 and 2 distinct............................................................... 2

– Antennula peduncle articles 1 and 2 fused.................................................................. 3

2. Uropod apices deeply or shallow subequal bifid, lateral process prominent, appendix masculina straight and distally acute.. 4

– Uropod apices deeply and evenly bifid, appendix masculina laterally curved........................ Cirolana siamensis

3. Uropod apices deeply subequal bifid, pleotelson apex linguiform with 8 RS...................................... 5

– Uropod apices shallow and evenly bifid; pleotelson narrow with 6 RS.............................. Cirolana stenoura

4. Pereopod 1 with setal fringe, appendix masculina minimum 1.6 times as long as endopod........................... 6

– Pereopod 1 without setal fringe, appendix masculina maximum 1.5 times as long as endopod........................ 7

5. Penial openings medially united (separated by less than 4% of sternal 7 width), appendix masculina tip with microtrichs... 8

– Penial openings separated by more than 5% of sternal 7 width, appendix masculina tip without microtrichs............. 9

6. Pereopod 1 setal fringe present on merus to propodus, appendix masculina 1.6 times as long as endopod...................................................................................................... Cirolana arafurae

– Pereopod 1 setal fringe present on carpus to propodus, appendix masculina 1.9 times as long as endopod..................................................................................................... Cirolana thailandica

7. Endopod width to length ratio 40%, exopod width to length ratio 30%............................. Cirolana leptanga

– Endopod width to length ratio 50%, exopod width to length ratio 40%....................... Cirolana peisanae sp. nov.

8. Appendix masculina 1.4 times as long as endopod; distally straight........................... Cirolana andamanensis

– Appendix masculina 1.5 times as long as endopod; distally recurved............................. Cirolana improceros

9. Pereopod 1 with a single and continuous row of RS on merus inferior margin; appendix masculina 1.8 times as long as endo- pod............................................................................. Cirolana molari sp. nov.

– Pereopod 1 with a double row of RS on merus inferior margin; appendix masculina 1.6 times as long as endopod............................................................................................. Cirolana duo sp. nov.