Rheocricotopus tatequintus Sasa 1996

Rheocricotopus (s. str.) tatequintus Sasa, 1996 Fig. 27, Table 24 Rheocricotopus tatequintus Sasa, 1996a: 32. Rheocricotopus (Rheocricotopus) tatequintus – Saether et al. 2000: 161. — Ashe & O’Connor 2012: 572. — Yamamoto & Yamamoto 2014: 298. — Fu et al. 2016: 271. Type material Holotype JAPAN – Toyama • ♂; Mt Tate; 9 Apr. 1986; M. Sasa leg.; NSMT, NSMT-I-Dip 4998 [No. 284: 58]. Paratypes JAPAN – Toyama • 2 ♂♂, 1 ♀; same data as for holotype; NSMT, NSMT [No. 284: 59–61]. Description Male (n = 3) Total length 3.0–3.3, 3.2 mm. COLOURATION. Thorax black, abdomen and legs uniformly dark brown. HEAD. Temporals 2–3, 3 (2). AR 1.13–1.16, 1.14. Clypeus with 6–8, 7 (2) setae. Lengths (μm) of Pm 1–5: 34–37 (2); 54–64 (2); 130–148 (2); 143–148 (2); 221–229 (2), respectively. Pm 4 /Pm 3 1.0–1.1 (2); Pm 5 / Pm 4 1.6 (2). Pm 3 with 1 (1) SCl. THORAX. Lateral Aps 4 (2), and medial Aps 0–2 (2). Ac 28 (1), and longest 22 (1) μm long; Dc 14–15 (2) including 2–3 (2) H; Pa 3 (2). HP (Fig. 27A) composed of large hole and small hole; large hole oblong, 0.26–0.28 (2) × as high as long. WING (Fig. 27B). Length 2.3–2.4, 2.4 mm. C extension slightly projected, 42–59, 48 μm long. VR 1.0–1.1, 1.0. R with 9–12, 10 setae, R 1 and R 4+5 without setae. AnL obtuse. Sq with at least 4. LEGS. P 1 with single ti spur 49–54, 52 μm long; P 2 with 2 ti spurs 20–22, 21 and 17–20, 18 μm long, respectively; P 3 with 2 ti spurs 47–49, 48 and 20 μm long and ti comb of 14–16, 15 bristles. Lengths and proportions of legs as in Table 24. ABDOMEN. Hypopygium (Fig. 27C) with AnP pointed apically, bearing 12 (1) setae. Gc (Fig. 27D) 209– 244, 231 μm long with finger-like, apically rounded SVo; IVo (Fig. 27E) triangular, apically with small dorsal projection. Gs 108–125, 117 μm long with convex outer margin; CD (Fig. 27F) low, somewhat broad. HR 1.92–2.06, 1.97. Female (n = 1) Total length 2.8 mm. COLOURATION. Similar to male. HEAD. Antenna 5-segmented. Lengths (μm) of Fm 1–5: 98, 69, 69, 59, 106. AR 0.36. Clypeus with 9 setae. Lengths (μm) of Pm 1–5: 37, 62, 138, 145, 241. Pm 4 /Pm 3 1.1, Pm 5 /Pm 4 1.7. Pm 3 with 2 SCl. THORAX. HP (Fig. 27G) with 2 holes, large hole 0.27 × as high as its length. Lateral Aps 3, medial Aps absent. Ac at least 17, Pa 3. WING. Length 2.4 mm. C extension 98 μm long. VR 1.0. R with at least 17, R 1 with at least 10, R 4+5 with at least 31. Sq with 6 setae. LEGS. P 1 with single ti spur 32 μm long; P 2 with 2 ti spurs, 22 and 20 μm long, respectively; P 3 with 2 ti spurs, 49 and 20 μm long, and with ti comb of 18 bristles. Lengths and proportions of legs as in Table 24. GENITALIA (Fig. 27H). S VIII with about 20 setae. Gca distinct. Gp VIII divided into rounded VlL and DmL. Gc IX well developed, with 12 setae on each side. Ce 76 μm long. No 75 μm long. SCa 116 μm long. Pupa and larva Unknown. Distribution The species is known only from the type locality, Mt Tate in Toyama Prefecture, Palaearctic Japan. Remarks We re-examined the holotype male, two male and one female paratypes of R. (s. str.) tatequintus Sasa, 1996. Although all the types are severely damaged during the mounting procedures, a digitate superior volsella is recognized in the males. The female thorax has a large humeral pit consisting of two holes as in the male thorax. Fu et al. (2016: 271) corrected the antennal ratio of 1.13–1.34 in the original description to 2.55 by their re-examination of the holotype, but our re-examination of all the male types (No. 284: 58–60), including the holotype (NSMT-I-Dip 4998, No. 284: 58), shows the true antennal ratio is 1.13–1.16, not such high re-calculated values. The male is a member of the reduncus group as defined by Moubayed-Breil & Ashe (2019: 36) in having the superior volsellae finger-like, resembling that of R. (s. str.) pyrenaeus Moubayed & Ashe, 2019 in the humeral pit consisting of a large hole and a small hole, the apically rounded finger-like superior volsella, and crista dorsalis broad, distinct. However, in R. (R.) tatequintus, the male antennal ratio is somewhat higher (1.1–1.2), the female antennal ratio is lower (AR 0.36), and the male wing has no seta on veins R 1 and R 4+5, whereas in R. (R.) pyrenaeus, the male antennal ratio is 0.84, the female antennal ratio is 0.65, and each of the male R 1 and R 4+5 possess two setae according to Moubayed & Ashe (2019: 41–42).