Kotov A.A.1, Stifter P.2 2006. Notes on the genus Ilyocryptus Sars, 1862 (Cladocera: Anmopoda: Ilyocryptidae). 6. South American I. denticulatus denticulatus Delachaux, 1919 and I. denticulatus freyi subsp.n. // Arthropoda Selecta. Vol.14 (for 2005). No.3: 207–218 [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, South America.

ABSTRACT. I. denticulatus denticulatus Delachaux, 1919 (Cladocera: Anomopoda: Ilyocryptidae), known to cladoceran investigators only from its first description, was redescribed based on the new material from highlands of northern Chile. It is a unique species among ilyocryptids in having of a large postero-lateral projection on the head shield and a very thick, ovoid process on the mandibular articulation. Also, a combination of large size, medial anus and not too numerous, exclusively single, straight and relatively small preanal teeth differentiates this species from all other known sordidus-like species. A new subspecies, I. denticulatus freyi subsp.n. found in few localities in southernmost portions of Chile and Argentina, differs from the nominotypical subspecies in having setules on the distal segments of basal lateral setae of antenna II three times or more longer than the diameter of its distal segment, and paired spines on their postabdomen markedly longer than the lateral setae. I. denticulatus denticulatus is found in a water body with salinity 8 ‰ (in the state of Tarapaca, Chile), which is the greatest recorded salinity for the genus.

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