Rheocricotopus Brundin 1956

Genus Rheocricotopus Brundin, 1956 Type species Chironomus effusus Walker, 1856, by original designation. Rheocricotopus Thienemann & Harnisch, 1932: 135. Nomen nudum. Rheocricotopus Brundin, 1956: 118. Rheocricotopus – Ashe & O’Connor 2012: 558. — Yamamoto & Yamamoto 2014: 296. Emended diagnosis Male Humeral pit on thorax small to large, occasionally absent (R. (P.) valgus Chaudhuri & Sinharay, 1983). Wing vein R usually with setae, occasionally bare (R. (P.) valgus). Superior volsella plate- or finger-like (the R. (s. str.) reduncus group); inferior volsella triangular, or digitate (the R. (P.) orientalis group). Gonostylus with apical, subapical, or median crista dorsalis (R. (P.) chinogodavarius sp. nov., R. (P.) protuberans sp. nov. and species of the R. (P.) orientalis group); occasionally crista dorsalis reduced or seemingly absent. Female Spermathecal ducts curved, occasionally with loop (R. (P.) nippobifasciatus sp. nov. and R. (P.) orientalis Wang, 1995). Pupa Frontal apotome usually without warts, except R. (P.) orientalis with low warts. Anteriorly directed spinules mostly present posterior to spine rows on tergites II–IV or II–V or on conjunctives II/III–IV/V or II/III–V/VI; occasionally these spinules absent (R. (P.) albulus sp. nov. and R. (P.) orientalis). Segment VIII usually with 4–5 LS-setae, occasionally with 3 bristle-like L-setae and 1 LS-setae (R. (P.) tirolus Lehman, 1969), or with 3 bristle-like L-setae only (R. (P.) albulus sp. nov. and R. (P.) orientalis). Larva Chaetulae basales 2, simple or apically bifid. Seta interna with 5–7 branches. Remarks Generic diagnoses have been given by Brundin (1956: 118), Lehmann (1969: 348), Saether (1969: 85; 1977: 97; 1986: 61) and Cranston et al. (1989: 234) for the adult; Lehmann (1969: 349), Coffman et al. (1986: 203) and Saether (1986: 62) for the pupa; and Cranston (1982: 130), Cranston et al. (1983: 195), Saether (1986: 63), Epler (2001: 7.134) and Andersen et al. (2013: 254) for the larva. Normally, the hairy eye, well-developed pulvilli, conventional anal point with lateral seta, obvious gonocoxite lobes and abdominal setation are still useful for separating Rheocricotopus from other Orthocladiinae; in addition, the acrostichals, antepronotals and wing vein setae are critical for the delimitation of the species, while the humeral pit, crista dorsalis and squamals vary both intraspecifically and interspecifically. In the pupa, the well-developed thoracic horn, posterior strong spine band and fringed anal lobe together with three strong macrosetae still work well for separating most of the Rheocricotopus from other orthoclads, but the lateral taeniate setation on T VII–VIII is found to vary greatly, also the anal fringe can be completely absent. In the larva, the well-developed ventromental plates with a round base and beard beneath are still useful in determining the Rheocricotopus larva, but the SI condition and length of body setae vary greatly. Although R. (P.) orientalis has rather unusual features for the genus, the number of species in the R. (P.) orientalis group came to be known as higher in the genus. Therefore, we emend the generic diagnosis to accommodate this expanded species group, as well as the other Chinese and Japanese species treated here. Key to the adult males of East Asian Rheocricotopus Brundin, 1956 1. Abdomen with or without yellow bands or markings. Superior volsella usually thin, triangular or roundly protruded medially ............................................(subgenus Psilocricotopus Saether, 1986) 2 – Abdomen unicoloured. Superior volsella thick, horn- or finger-shaped, roundly or triangularly protruded ....................................................................(subgenus Rheocricotopus Brundin, 1956) 31 2. Abdomen bicoloured, with distinct colour pattern (Figs 16A, 22A, 24A). Foretibia with or without pale band ........................................................................................................................................... 3 – Abdomen entirely brown, without distinct colour pattern. Fore tibia uniformly brown, without pale band ................................................................................................................................................. 20 3. Wing not cuneiform, anal lobe obtuse (Fig. 11D) ............................................................................ 4 – Wing cuneiform, anal lobe much reduced (Fig. 13C) ...................................................................... 5 4. Tergites VIII–IX entirely yellow. Humeral pit absent. Costal extension much produced (Fig. 11D) ......................................................................................... R. (P.) valgus Chaudhuri & Sinharay, 1983 – Tergites VIII–IX brown. Humeral pit large, circular. Costal extension slight (Fig. 21C) ................... ................................................................................................................ R. (P.) monovittatus sp. nov. 5. Foretibia bicoloured (Fig. 2C–D) ..................................................................................................... 6 – Foretibia uniformly brown ................................................................................................................ 8 6. Gonostylus with crista dorsalis at middle (Fig. 17J) ...................... R. (P.) chinogodavarius sp. nov. – Gonostylus with crista dorsalis at subapex (Fig. 6E–F) ................................................................... 7 7. Tergite II yellow (Fig. 2A–B). Hypopygial anal point slender, apically pointed; superior volsella relatively thick, triangular (Fig. 2H) ................................... R. (P.) bifasciatus Wang & Zheng, 1991 – Tergite II brown. Hypopygial anal point robust, apically blunt; superior volsella thin, roundly protruded medially (Fig. 14G) ........................................................................ R. (P.) albulus sp. nov. 8. Inferior volsella triangular (Fig. 18E) ............................................................................................... 9 – Inferior volsella digitate (Fig. 12A, E) ........................................................................................... 15 9. Crista dorsalis indistinct or absent (Wang & Zheng 1991: 100 fig. 1c) .............................................. ................................................................................................... R. (P.) tibialis Wang & Zheng, 1991 – Crista dorsalis distinct even if small (Fig. 19E) ............................................................................. 10 10. Tergites VI–VIII partly brown (Fig. 18A) ................................................ R. (P.) fasciolatus sp. nov. – Tergites VI–VIII entirely brown ..................................................................................................... 11 11. Tergite II entirely brown (Fig. 16A–B) ....................................................... R. (P.) binotatus sp. nov. – Tergite II entirely or partly yellow .................................................................................................. 12 12. Antepronotal setae divided into medial and lateral groups (Fig. 6E). Superior volsella thick, roundly protruded inwards ............................................................................... R. (P.) oiraprimus Sasa, 1991 – Antepronotal setae lateral only (Fig. 8A). Superior volsella thin, triangular (Fig. 19D) ............... 13 13. Tergite IV entirely brown (Fig. 19A) ...................................................... R. (P.) hanmiensis sp. nov. – Tergite IV entirely yellow (Figs 22A, 24A) .................................................................................... 14 14. Tergite V entirely brown. Veins R 1 and R 4+5 bare (Fig. 24C) ................. R. (P.) yunnanensis sp. nov. – Tergite V brown with transverse yellow band on anterior ¼–½. Veins R 1 and R 4+5 setiferous (Fig. 22A) ........................................................................................ R. (P.) nippobifasciatus sp. nov. 15. Inferior volsella short, apically lump-like (Fig. 12A) ...................... R. (P.) kongi Lin & Wang, 2020 – Inferior volsella long, slender (Figs 12E, 13D) .............................................................................. 16 16. Tergite IX posterolaterally with setiferous lobes (Fig. 12E) ................ R. (P.) orientalis Wang, 1995 – Tergite IX posterolaterally without lobes (Fig. 13D) ...................................................................... 17 17. Hypopygial anal point constricted at middle (Yan & Wang 2004: 561 fig. 3) .................................... ................................................................................................ R. (P.) constrictus Yan & Wang, 2004 – Hypopygial anal point without middle constriction ....................................................................... 18 18. Tergite IX posterolaterally with setal tufts (Wang & Saether 2001: 239 fig. 2d) ................................ ............................................................................................... R. (P.) villiculus Wang & Saether, 2001 – Tergite IX without any setal tuft ..................................................................................................... 19 19. Tergite VII entirely brown (Wang & Saether 2001: 239 fig. 1c). R 1 and R 4+5 setiferous (Wang & Saether, 2001: 239 fig. 1b) ................................................... R. (P.) calviculus Wang & Saether, 2001 – Tergite VII entirely yellow (Fig. 13A). R 1 and R 4+5 bare (Fig. 13C) ....... R. (P.) bannaensis sp. nov. 20. Acrostichal setae indistinct or absent (Fig. 3B) .............................................................................. 21 – Acrostichal setae distinct (Fig. 22B) .............................................................................................. 23 21. Gonostylus