Rheocricotopus (Psilocricotopus) amamipubescius

Rheocricotopus (P.) amamipubescius (Sasa, 1990) Fig. 1, Table 1 Eukiefferiella amamipubescia Sasa, 1990: 127. Rheocricotopus (Psilocricotopus) nudisquamus Makarchenko & Makarchenko, 2009: 122. Syn. nov. Rheocricotopus (Rheocricotopus) amamipubescius – Saether et al. 2000: 161. — Ashe & O’Connor 2012: 568. — Yamamoto & Yamamoto 2014: 297. Rheocricotopus (Psilocricotopus) nudisquamus – Ashe & O’Connor 2012: 566. Rheocricotopus (Psilocricotopus) amamipubescius – Yamamoto et al. 2015: 108. Type material Holotype of Eukiefferiella amamipubescius JAPAN – Kagoshima • ♂; Amami-oshima Island, Yakugachi River; 18 Mar. 1989; M. Sasa leg.; NSMT, NSMT-I-Dip 4690. The type specimen of R. (P.) nudisquamus was not examined. Other material examined CHINA – Fujian • 1 ♂; Nanping, Wuyishan, Mt Wuyi NNR, Tongmu; 27°45′ N, 117°40′ E; 850 m a.s.l.; 9 Aug. 2014; H.Q. Tang leg.; JNU, JNU 190130003. – Guangdong • 1 ♂; Shaoguan, Ruyuan, Nanling NNR, “ Mangshan ” [Mt Mang]; 24°55′ N, 113°01′ E; 1054 m a.s.l.; 25 Jul. 2020; Z. Li leg.; JNU, JNU 21081601. JAPAN – Shizuoka • 1 ♂; Shimizu, Ihara River; 35°4′ N, 138°27′ E; 202 m a.s.l.; 25 Sep. 1990; H. Niitsuma leg.; PCHN. Description Male (n = 4) Total length 2.1 (2) mm. COLOURATION. Body mostly brown. Thorax with Sct, Pn, Pe and 3 scutal vittae dark brown; pleural membrane yellow. Abdomen light brown, occasionally anterior few tergites somewhat paler. Legs brown; P 1 somewhat darker than P 2–3. HEAD. Temporals 3–4, 4. AR 0.31–0.46, 0.41 (3). Clypeus with 6–11, 9 setae. Lengths (μm) of Pm 1–5: 34–37, 36 (3); 49–59, 56 (3); 111–143, 130 (3); 111–135, 123 (3); 221–285, 259 (3), respectively. Pm 4 / Pm 3 0.9–1.0, 1.0 (3); Pm 5 /Pm 4 2.0–2.2, 2.1 (3). Pm 3 with 9–13, 11 (3) SCl on 2–3, 2 (3) subapical oval depressions; Pm 4 without SCl. THORAX. Lateral Aps 5–6 (2). Ac 11–15 (2), and longest 8–11 (2) μm long; Dc 8 (2), including 2 (2) H; Pa 3 (2). Scts 4–5 (2), uniserial. Humeral pit (Fig. 1A) moderately large, oval. WING (Fig. 1B). Length 1.5–2.1, 1.8 mm. C extended much beyond end of R 4+5; its extension 111–123, 119 μm long. VR 1.1. R with 4–10, 8 setae; R 1 with 0–5, 3 setae, and R 4+5 with 5–10, 8 setae. AnL much reduced, wing widest at around end of Cu 1. Squama with 0–1, 1 seta. LEGS. P 1 with single ti spur, 30–44, 36 μm long. P 2 with 2 ti spurs, 12–17, 16 and 12–16, 14 μm long, respectively; P 3 with 2 ti spurs, 44–51, 46 and 15–21, 18 μm long, respectively. P 2 and P 3 without Sch; P 3 with ti comb of 12–14, 13 bristles. Lengths and proportions of legs as in Table 1. ABDOMEN. Hypopygium (Fig. 1C) with AnP pointed apically, bearing 6–18, 10 lateral setae. Gc 155–172, 165 μm long, 2.9–3.6, 3.2 × as long as broad at middle, with SVo somewhat thick, protruded roundly; and IVo triangular, double-layered, dorsally rounded at apex. Gs (Fig. 1D–E) 66–76, 71 μm long, roundly convex in outer margin; CD nearly triangular, relatively broad, occasionally very low or indistinct. HR 2.22–2.39, 2.32. Female, pupa and larvae Unknown. Distribution The present species has been known from Palaearctic and Oriental Japan, Oriental China and the Russian Far East. Remarks A re-examination of the holotype of Eukiefferiella amamipubescia Sasa, 1990 revealed that the male is characterized by the somewhat large, oval humeral pit; the wing with a much-reduced anal lobe, and a long costal extension and no squamal seta; the legs with well-developed pulvilli; the roundly protruded superior volsella; and the triangular, broad, occasionally low, crista dorsalis. The species belongs to the genus Rheocricotopus Brundin, 1956, rather than to Eukiefferiella Thienemann, 1926. The low, broad crista dorsalis may suggest that it is a member of Rheocricotopus s. str. However, a male (JNU 190130003) newly collected from Fujian Province, China, has a triangular, high but broad crista dorsalis in the right gonostylus, but a low crista dorsalis in the left. The difference in the shape may occur from the mounting orientation. A cuneiform wing with squamal setae reduced in number is often found in the subgenus Psilocricotopus rather than in Rheocricotopus s. str. Although the immature stages are unknown, in fact, the species seems to be a member of subgenus Psilocricotopus. This species was recorded subsequently under the name Eukiefferiella amamipubescia Sasa, 1990 from Toyama Prefecture, also in Palaearctic Japan by Sasa & Okazawa (1992: 94). Furthermore, Sasa & Suzuki (1993: 114) redescribed this species as a member of Eukiefferiella from Amami Island in Oriental Japan. Based on examinations of voucher specimens housed in NSMT; however, Yamamoto et al. (2015: 108) pointed out that the former species is R. (P.) oiraprimus Sasa, 1991 and the latter species should be treated as R. (P.) tokarakeleus Sasa & Suzuki, 1995. The male of R. (P.) nudisquamus Makarchenko & Makarchenko, 2009 does not differ significantly in morphology from this species. Without having examined the holotype, we regard the species to be a junior synonym of R. (P.) amamipubescius. The male is similar to that of R. (P.) godavarius Lehmann, 1969 collected from Nepal in the low antennal ratio of 0.31–0.46, cuneiform wings with a very long costal extension and reduced number of squamal setae, and in the triangular inferior volsella with a rounded apex, but separable from it in the brown tergite IV, the somewhat large, oval humeral pit, and the relatively large, roundly protruded superior volsella.According to Lehmann (1969: 361–362, 370 fig. 9, 372 fig. 14b), the latter has a yellow tergite IV, small humeral pits consisting of fused several small holes, and relatively thin, triangular superior volsellae.