Rheocricotopus tamahumeralis Sasa 1981

Rheocricotopus (s. str.) tamahumeralis Sasa, 1981 Figs 25–26, Table 23 Rheocricotopus tamahumeralis Sasa, 1981: 92. Rheocricotopus (Rheocricotopus) tamahumeralis – Sasa & Okazawa 1992: 103. — Saether et al. 2000: 161. — Ashe & O’Connor 2012: 572. — Yamamoto & Yamamoto 2014: 298. — Fu et al. 2016: 270. Type material Holotype JAPAN – Tokyo • ♂ with Pe; tributary Minamiasakawa River of Tama River; 2 Jan. 1980; M. Sasa leg.; NSMT, NSMT-I-Dip 4527 [No. 56: 01]. Other material examined JAPAN – Fukushima • 2 ♂♂, 1 Pe; Iwaki, Yaguki; 37°8′ N, 140°54′ E; 123 m a.s.l.; 5–10 May 2014; H. Niitsuma leg.; PCHN. – Kanagawa • 2 ♂♂, 2 Pe; Kiyokawa, Miyagase; 35°30′ N, 139°12′ E; 290 m a.s.l.; 23 Feb. 1994 (emerged 25–28 Mar. 1994); H. Niitsuma leg.; PCHN • 2 ♂♂, 2 Pe; 1 ♀ with 1 Pe; same data as for preceding; 7 Feb. 1998 (emerged 7 Mar. 1998); PCHN. – Shizuoka • 1 L; Ikawa, Dainichi Pass, stream; 35°11′ N, 138°15′ E; 1100 m a.s.l.; 15 Sep. 1996; H. Niitsuma leg.; PCHN • 6 ♂♂ with 6 Pe, 3 ♀♀ with 3 Pe and 1 Le, 5 Pe, 3 Le; same data as for preceding; 4 May 1998 (emerged 10–30 May 1998) • 1 ♂ with 1 Pe, 2 ♀♀ with 2 Pe, 1 ♀ (pharate); Uchimaki River; 35°01′ N, 138°20′ E; 122 m a.s.l.; 20 Apr. 1997 (emerged 25–28 Apr. 1997); H. Niitsuma leg.; PCHN • 1 ♂ with 1 Pe, 1 ♀ with 1 Pe and 1 Le; Shimizu, Ihara River; 35°4′ N, 138°27′ E; 202 m a.s.l.; 15 Mar. 1990 (emerged 20.iii.1990); H. Niitsuma leg.; PCHN • 1 ♀ with 1 Pe; Aoi-ku, Ashikubo, Harada River; 35°2′ N, 138°22′ E; 77 m a.s.l.; 8 Apr. 1995 (emerged 25 Apr. 1995); H. Niitsuma leg.; PCHN. – Tochigi • 1 ♀ with 1 Pe; Ichikai, Miage; 36°36′ N, 140°7′ E; 115 m a.s.l.; 18 Mar. 1989 (emerged 25 Mar. 1989); H. Niitsuma leg.; PCHN. CHINA – Jilin • 1 ♂ with 1 Pe; Antu, Mt Changbai, north slope; 42°03′ N, 128°03′ E; 1835 m a.s.l.; 11 Aug. 2022; H.Q. Tang leg.; JNU, JNU 22082002. – Jiangsu • 1 ♂; Lianyuangang, Mt Yuntai, site 2; 34°40′ N, 119°19′ E; 400 m a.s.l.; 8 May 2014; H.Q. Tang leg.; JNU. – Zhejiang • 1 ♂, 1 ♀; Xianju, south gate of Xianju National Park; 28°43′ N, 120°34′ E; 110 m a.s.l.; 10 Nov. 2019; H.Q. Tang leg.; JNU 191118001. – Guangdong • 1 ♂ (pharate); Shaoguan, Renhua, Zhongshan; 25°15′ N, 113°36′ E; 500 m a.s.l.; 15 Feb. 2023; Y.R. He and X. Dong leg.; JNU, JNU 23022307. – Hainan • 1 ♂; Qiongzhong, Limuling, Mt Limu; 19°10′ N, 109°45′ E; 830 m a.s.l.; 15 Apr. 2016; H.Q. Tang leg.; JNU. – Yunnan • 2 ♂♂; Nujiang, Fugong, seep in Mt Biluo; 26°33′ N, 98°54′ E; 1790 m a.s.l.; 15 Oct. 2017; H.Q. Tang leg.; JNU, JNU 171027023, 171027025 • 1 ♂ (teneral), 1 ♂ (pharate); Shangri-La, Gezan, unnamed stream; 28°03′ N, 99°46′ E; 3130 m a.s.l.; 19 Jun. 2018; H.Q. Tang leg.; JNU, JNU 180706008 • 1 ♂; Dali, Qingbi stream; 25°39′ N, 100°09′ E; 2350 m a.s.l.; 14 Feb. 2022; X.F. Li leg.; JNU • 2 ♂♂ with 2 Pe, 1 ♀ (pharate), 4 Pe; Ximeng, Mengsuo, Lake Mengsuo; 22°38′ N, 99°35′ E; 1270 m a.s.l.; 26 Apr. 2022; Y.J. Liang leg.; JNU. Description Male (n = 23) Total length 1.9–3.0, 2.4 (22) mm. COLOURATION. Body mostly dark brown with pale pleural membrane, including HP, on thorax. HEAD. Temporals 2–7, 4 (21). AR 0.73–1.27, 1.00. Clypeus trapezoid with 8–18, 11 setae. Lengths (μm) of Pm 1–5: 30–42, 35 (21): 39–69, 57 (21); 76–160, 109 (21); 91–160, 114 (21); 145–246, 197 (18), respectively. Pm 4 /Pm 3 0.9–1.3, 1.0 (21); Pm 5 /Pm 4 1.5–2.1, 1.7 (18). Pm 3 with 1–8, 3 (21) SCl; occasionally 1 (1) SCl present on Pm 4. THORAX (Fig. 25A). Lateral Aps 0–6, 2 (19). Ac 11–26, 20 (21), and longest 13–23, 17 (21) μm long; Dc 6–16, 11 (20), H absent; Pa 1–5, 3 (21). Scts 4–11, 6 (17). Humeral pit (Fig. 25B–D) consisting of large, triangular or rectangular pit, and small elongate pit; large pit 0.43–0.81, 0.63 (22) × as wide as its length; occasionally small pit indistinct partly. WING (Fig. 25E). Length 1.4–2.5, 1.8 (21) mm. C extension slightly projected, 20–49, 35 (22) μm long. VR 1.0–1.1, 1.1 (21). R basally with 3–10, 5 (22) setae; R 1 and R 4+5 usually without setae, very rarely each with 1 (1) seta. AnL obtuse. Sq with 0–8, 4 (22) setae. LEGS. P 1 with single ti spur 37–54, 43 (22) μm long; P 2 with 2 ti spurs 18–25, 21 (21) and 16–22, 19 (21) μm long, respectively; P 3 with 2 ti spurs 39–52, 45 (22) and 15–25, 19 (22) μm long, respectively, and ti comb of 12–15, 13 (18) bristles. Mid ta 1 usually without Sch, occasionally with 5 (1) Sch. Lengths and proportions of legs as in Table 23. ABDOMEN. Hypopygium (Fig. 25F) with AnP sharply pointed, bearing 7–14, 11 (22) lateral setae. Gc 138– 229, 184 μm long, 3.3–4.1, 3.7 (22) × as long as broad at middle; SVo (Fig. 25G–H) posteriorly projected, apically pointed or blunted; IVo (Fig. 25I–J) triangular, usually with bare beak-like, occasionally blunt, dorsal apex. Gs (Fig. 25K–N) 59–98, 75 μm long, roundly convex in outer margin, with low and broad CD; occasionally CD indistinct. HR 2.25–2.69, 2.47. Female (n = 9) Total length 1.6–2.7, 2.0 mm. COLOURATION. Similar to male. SCa brown. HEAD. Temporals 2–5, 3. Antenna 5-segmented; Fm 5 101–123, 109 μm long, nearly as long as combined length of Fm 3 and Fm 4; AR 0.40–0.49, 0.45. Clypeus with 8–13, 12 setae. Lengths (μm) of Pm 1–5: 30–39, 35 (6); 49–57, 53 (6); 86–98, 92 (6); 98–118, 107 (6); 192–219, 203 (6), respectively. Pm 4 /Pm 3 1.1–1.2, 1.2 (6); Pm 5 /Pm 4 1.7–2.1, 1.9 (6). Pm 3 with 2–5, 4 SCl; Pm 4 without Scl. THORAX. Lateral Aps 2–5, 3 (7). Ac 19–29, 23 (8); Dc 11–15, 14, including 1–4, 2 H; Pa 3–4, 3. Scts 5–6, 6 (8). WING. Length 1.5–2.1, 1.7 mm. C extension slightly projected. VR 1.0–1.1, 1.0. R with 5–11, 9; R 1 with 0–7, 4; R 4+5 with 13–19, 15 setae. AnL obtuse. Sq with 3–9, 5 setae. LEGS. P 1 with single ti spur 24–28, 26 μm long. P 2 with 2 ti spurs, both 16–21, 18 μm long; without Sch on ta 1. P 3 with 2 ti spurs 42–46, 44 and 16–23, 18 μm long; with comb of 11–14, 13 bristles. Lengths and proportions of legs as in Table 23. GENITALIA (Fig. 25O). S VIII with 8–15, 12 setae; Gca distinct. Gp VIII divided into rounded VlL and narrow DmL; ApL distinct between VlLand DmL. T IX (Fig. 25P) divided into 2 protrusions, with 11–19, 14 setae in total. Gc IX well developed with 6–10, 7 setae on each side. PgP triangular. Ce 51–74, 61 μm long. No 101–128, 110 μm long. L without microtrichia. SCa ovoid, 81–89, 85 (2) μm long, 1.3– 1.5, 1.4 (2) × as long as broad, with conical neck placed somewhat asymmetrically; ducts without loop. Pupa (n = 30) Total length 2.5–3.6, 3.0 mm. COLOURATION. Exuviae generally pale brown; Apo, and central and posterior spines on abdominal tergites dark. CEPHALOTHORAX. FA (Fig. 26A) weakly rugulose, with FS 57–111, 81 (18) μm long. Thoracic horn (Fig. 26B) club-shaped, 241–308, 266 μm long, 4.1–5.8, 5.0 (18) × as long as broad. Lengths (μm) of Pc 1–3: 44–74, 57 (28); 27–59, 39 (27); 17–39, 26 (28), respectively. Three Pc arranged in triangle. Length (μm) of Dc 1–4: 44–74, 57 (28); 27–59, 39 (27); 17–39, 26 (28); 30–69, 45 (29), respectively. Four Dc arranged in straight line; last 3 grouped. Distances (μm) of Dc 1 –Dc 2, Dc 2 –Dc 3, Dc 3 –Dc 4: 101–157, 122 (29); 12–57, 22 (28); 12–47, 21 (28), respectively. ABDOMEN (Fig. 26C). T I without any spinulation. T II and VIII with triangular patch of posteromedian spinules. T III–V with more or less extensive spinulation. T VI with posterior spinulation. T VII with vertically long patch of median spinules. T IX with anterior spinulation. Weak anterolateral spinulation present on T II–VIII. T IV–VI with one median rounded patch of spines; weak to strong median spine patch (Fig. 26D) frequently present on T III. Rows of simple spines present on posterior margins of T II–VII; posterior spines of T II not recurved, smaller than those of T III–VI; posterior spines on T VII (Fig. 26E) usually weak, occasionally strong. Anteriorly directed spinules posterior to spine rows on T II–V. PSB somewhat low on A II–III. Usually A I with 1 L-seta, II–IV each with 3 L-setae, V–VI each with 4 L-setae, VII with 4 LS-setae, VIII with 5 LS-setae; occasionally A IV with 4 L-setae, V with 3 L-setae.AL 197–258, 224 μm long, 1.7–2.2, 2.0 (27) × as long as broad, with 9–16, 12 lateral taeniae on posterior ⅔– 4 /5; male genital sac 1.0–1.2, 1.1 (6) as long as AL. Larva (n = 6) Total length 4.0 (1) mm. Length of head capsule 358 (1) μm. COLOURATION. Head yellow with dark brown M, apical ⅔ of mandible, and Po. HEAD (Fig. 26F). IC 0.68 (1). PM 172–192, 184 (5) μm long. Dorsal surface with frontoclypeus, labral sclerite and lateral sclerites. Labrum with bifid SI. Lengths (μm) of 1st to 5th antennal segments: 49–55, 53 (5); 13–16, 14 (5); 7–9, 8 (5); 5–6, 5 (5); 6–7, 7 (5), respectively. AR 1.5–1.7, 1.5 (5). First segment (Fig. 26G) 2.9–3.7, 3.2 (5) × as long as broad, with ring organ located 0.15–0.20, 0.17 (5) from base and 2 SA located 0.09–0.19, 0.14 (5) and 0.50–0.66, 0.60 (5), respectively, from base; with Bl 29–33, 31 (2) μm long, reaching 4 th segment; with ABl 10–15, 12 (3) μm long. Second segment apically with LO 7–8, 7 (5) μm long, and St 2–3, 3 (4) μm long. Labrum with Pm 59–65, 63 (5) μm long. Mandible (Fig. 26H) 114–124, 119 (5) μm long, with apical tooth and 3 inner teeth; apical tooth shorter than combined width of these inner teeth; Si bearing 6–7 weakly serrated branches. Maxilla (Fig. 26I) with PG consisting of minute, indistinct teeth; anterior LCh 3.0–4.0, 3.5 (5) × as long as broad. M (Fig. 26J) with 2 median and 5 pairs of lateral teeth; median tooth without accessary tooth; combined width of 2 median teeth 24–29, 27 (5) μm. VmP 11–20, 14 μm wide at most, with 16–22, 20 beard setae beneath. BODY. With setae, 54–73, 62 (4) μm long. Pc (Fig. 26K) 23–24, 23 (3) μm long, 1.4–1.8, 1.6 (3) × as long as broad, with single spur and 3 AS. PP with 16 claws; small claws (Fig. 26L) squashed in shape. Distribution The species has been known from Palearctic Japan and China, and Oriental China. Remarks The species was described based on adults and pupae from a tributary river of the Tama in Tokyo, Japan. In the original description of the male, Sasa (1981: