Identification key for the species and subspecies of Ilyocryptidae
1a Valves with lateral projection................................................................................................................................................................................................ 2
1b Valves without lateral projection........................................................................................................................................................................................... 3
2a Spine on the second segment of endopodite of antenna bi-segmented............................................................................. Ilyocryptus paranaensis inarmatus
2b Spine on the second segment of endopodite of antenna not segmented......................................................................... Ilyocryptus paranaensis paranaensis
3a Preanal margin of postabdomen with duplicated denticles (one or more)............................................................................................................................ 4
3b Preanal margin of postabdomen with regular denticles........................................................................................................................................................ 5
4a Distalmost part of postanal margin of postabdomen with 4-5 rudimentary setae;up seven long lateral setae..................... Ilyocryptus cuneatus brasiliensis
4b Distalmost part of postanal part of postabdomen with eight rudimentary setae;8-9 long lateral setae........................... Ilyocryptus silvaeducensis paraensis
5a Postanal part of postabdomen with 3-4 long lateral setae;a long“gap” between proximalmost lateral seta and anal margin.............................................6
5b Postanal part of postabdomen with5-7 lateral setae;“gap” not developed .................................................................................................... Ilyocryptus sarsi
6a Setae on the posterior margin of carapace with inflated base and armed with a single spine.................................................................... Ilyocryptus spinifer
6b Setae on the posterior margin of carapace with regular morphology,without spine .............................................................................. Ilyocryptus plumosus