Ilyocryptus spinifer Herrick, 1882

Body sub-ovoid or triangular shaped, dorsal keel well developed, molting incomplete; setae on the posterior margin of valves with inflated base and armed with a long and sharp spine, setulae present; posteriormost setae on the valves armed with setulae. Head triangular shaped, fornices prominent and with a projection in the region of mandibular articulation; spine on the second segment of endopodite of antenna longer than midlength of the third segment. Postabdomen large, preanal part shorter than postanal; marginal denticles of preanal part with regular morphology, relatively long; 16-14 marginal spines of similar length; 3-5 long lateral setae about 4-5 times longer than marginal spines; a long “gap” between proximalmost lateral seta and anal margin; basal spines on the postabdominal claw of different length.

Comments: This is a cosmopolitan species. It is the most commonly found Ilyocryptidae taxon in Brazilian continental waters (Fig. 3G). The morphological variation exhibited by this species was described by Elmoor-Loureiro (1997), Kotov & Williams (2000), Kotov & Dumont (2000), and Kotov & Štifter, 2006.