Rheocricotopus (Psilocricotopus) okifoveatus Sasa, 1990

Yamamoto, Nao & Yamamoto, Masaru, 2018, Taxonomic information on some Japanese Chironomidae (Diptera) described by Dr. M. Sasa (†), Zootaxa 4514 (4), pp. 516-528 : 518

Rheocricotopus (Psilocricotopus) okifoveatus Sasa, 1990

Rheocricotopus okifoveatus Sasa, 1990: 129

Rheocricotopus chalybeatus: Sasa & Hasegawa, 1988: 239 ; Sasa & Suzuki, 2000a: 6, misidentification.

Specimens examined: Japan, Ryukyus, Okinawa Pref.: Okinawa Is., Kochinda, 5♂♂, 28. i. 1982 (specimens No. 65:86, 65:95-98); Ryutan Lake , 7. xii. 1981 (specimens No. 65:87-89); Hijagawa, ♂, 11. xii. 1981 (specimen No. 65:85); Hijagawa, ♂, 14. xii. 1981 (specimen No. 65:79); Miyako Is., Tanane, 3♂♂, 2. ii. 1982 (specimens No. 65:34, 99-100); Ishigaki Is., ♂, 2♀♀, 1. ii. 1982 (specimen No. 65:91–93) .

Rheocricotopus okifoveatus strongly resembles R. chalybeatus in many morphological characters. The former is separable from the latter by having a distinct crista dorsalis on the gonostylus. All the specimens examined have a distinct crista dorsalis. So, we determined them as R. okifoveatus . Although we could not examine the specimens reported from Amami-Oshima Island by Sasa and Suzuki (1993), our own personal materials collected from this area are identified as R. okifoveatus . Hitherto, we have no data that R. chalybeatus is distributed from south of Amami Island. Two slides numbered as 65:91 and 65:92 contain specimens of Smittia pratorum and R. okifoveatus , and Pseudosmittia nisharaensis and R. okifoveatus , respectively.