Rheocricotopus (Psilocricotopus) Saether 1986

Subgenus Psilocricotopus Saether, 1986 Psilocricotopus Saether, 1986: 72. Psilocricotopus – Ashe & O’Connor 2012: 559. — Yamamoto & Yamamoto 2014: 296. Type species Cricotopus atripes Kieffer, 1913 by original designation. Emended diagnosis Male Gonocoxite with superior volsella triangular or rounded, thin to relatively thick, never with digitate or horn-like projections; inferior volsella triangular, often double-layered apically, or digitate (the orientalis group). Crista dorsalis usually triangular and small at subapex of gonostylus; occasionally low and broad (R. (P.) togakuroasi (Sasa & Okazawa, 1992)), or indistinct (R. (P.) amamipubescius (Sasa, 1990) and R. (P.) tibialis Wang & Zheng, 1991), or large (R. (P.) binotatus sp. nov., R. (P.) chinogodavarius sp. nov., R. (P.) fasciolatus sp. nov., R. (P.) protuberans sp. nov. and the orientalis group). Female Spermathecal ducts usually curved, occasionally looped. Pupa Frontal apotome usually smooth, occasionally with low warts (R. (P.) orientalis Wang, 1995). Abdominal tergites III–VI usually without median patch of spines or spinules, occasionally with distinct median cluster of several spines (R. (P.) togakuroasi). Remarks Subgeneric diagnoses were given by Saether (1986: 72) and Cranston et al. (1989: 234, in key) for the adult; Coffman et al. (1986: 204, in key) and Saether (1986: 72) for the pupa; and Saether (1986: 72) and Andersen et al. (2013: 254, in key) for the larva. Here, emendations for adult male and pupal diagnoses are given mainly based on newly collected specimens from China and Japan. The superior volsella, the inferior volsella and the crista dorsalis, as well as the abdominal colouration are more or less diverse in the male morphology. In addition, the presence of the pupa having median spine patches on the pupal tergites IV–VI may obscure the boundary between the subgenera Psilocricotopus Saether, 1986 and Rheocricotopus s. str. Brundin, 1956. Based on the adult morphology, Wang & Saether (2001: 240) wrote: “However, the striking coloration, peculiar genitalia, complete absence of humeral pit and the crista dorsalis which do not conform to any of the subgenera lead us to suggest that the orientalis group form the sister group of the subgenus Psilocricotopus or of the full genus and may deserve subgeneric or even generic rank.” However, our examinations of the males of this species group revealed that these adults actually do have humeral pits. Rheocricotopus (P.) protuberans sp. nov. and R. (P.) chinogodavarius sp. nov. possess large median crista dorsalis. The bicoloured abdomen and the third palpomere bearing many sensilla clavata, regarded by Wang & Saether (2001: 240) as features peculiar to the orientalis group actually occur not only in the orientalis group, but also in the other species groups. Further, the pupa of R. (P.) orientalis resembles that of R. (P.) albulus sp. nov. in lacking frontal setae and any row of spinules posterior to spine rows on tergites III–V or on conjunctives III/IV–V/VI, and in having three pairs of L-setae on segments II–VIII and unfringed anal lobes. Certainly, the digitate inferior volsella is unique within Rheocricotopus, and separates the orientalis group from the other species groups in Psilocricotopus. On the other hand, pupal morphology appears to pull back the orientalis group into the subgenus Psilocricotopus. The subgenus Psilocricotopus currently includes four species groups: the atripes group, the chalybeatus group, the godavarius group, and the orientalis group.