Kotov A.A.1, Stifter P.2 2006. Notes on the genus Ilyocryptus Sars, 1862 (Cladocera: Anomopoda: Ilyocryptidae). 8. Ilyocryptus isanensis sp.n. from North-East Thailand // Arthropoda Selecta. Vol.14 (for 2005). No.3: 229–239 [in English].

1 A.N. Severtsov Institute of Ecology and Evolution, Leninsky Prospect 33, Moscow 119071 Russia.

2 Smetanova 25, Benatky nad Jizerou 29471 Czech Republic.

KEY WORDS: Cladocera, Anomopoda, Ilyocryptus, morphology, systematics, Asia, Thailand.

ABSTRACT. Historically, all populations of Ilyocryptus Sars, 1862 (Cladocera: Anomopoda: Ilyocryptidae) with complete moulting and the anus positioned medially on the postabdomen were assigned to Ilyocryptus agilis Kurz, 1878, a presumed cosmopolitan species. Recently, populations previously regarded as I. agilis from the Neotropics and tropical Africa were determined to be separate species. Likewise, we found that populations in NE Thailand represented a new species, Ilyocryptus isanensis sp.n. (Ilyocryptidae, Anomopoda, Cladocera). I. isanensis differs from Palearctic I. agilis in possessing: (1) a less compressed body with a low dorsal keel; (2) short setae at the postero-ventral angle of valve; (3) numerous, fine additional spinules near the preanal teeth; (4) shorter preanal teeth; (5) armature of largest seta of outer distal lobe of limb I; (6) armature of four setae near inner-distal margin of limb IV; (7) fine setules on limb VI; (8) well-developed column-like projections on the ephippium; and (9) a thicker antenna I in males.

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