Sympotthastia takatensis (Tokunaga)

Liu, Wenbin, Ferrington Jr, Leonard C. & Wang, Xinhua, 2016, Sympotthastia wuyiensis sp. n. from China, with description of the immature stages of S. takatensis (Tokunaga) (Diptera, Chironomidae), Zootaxa 4126 (3), pp. 427-434 : 428-430

Sympotthastia takatensis (Tokunaga)

( Figs. 1–9 )

Syndiamesa takatensis Tokunaga 1936 , 59: 531; Tokunaga 1937, 49 Sympotthastia Knorensis Makarcheko, 1984: 91

Sympotthastia toyamayezea Sasa 1996: 44

Sympotthastia takatensis Makarcheko 1994 , 20 (1): 51; Wang 2000: 634; Ashe & O’Connor 2009: 331

Diagnositic characters: Male imagines: AR 3.19–4.26; Anal point spiniform; aedeagal lobe sharp as a golf-club. Pupal stage: anterior thoracic setation strong; dorsocentral setae nearly equidistant; small points of tergite II much less extensive; L 3 in segment VI simple; Pc2 branched. Larvae stage: the third and fourth inner tooth of mandible wider and bigger than remaining; AR 2.06–2.36.

Materials examined. 1³, 1P and 2L, China: Liaoning Province, Benxi City, Huanren Manchu Autonomous County, Laotuding National Nature Reserve, 41°32’45’’N, 124°89’13’’E. iv.28.1992. J. C. Wang, sweep net. 3³³ and 2L, China: Tianjin City, Ji County, Yuqiao Lake, 40°04’11’’N, 117°49’88’’E, iii.31.1988, X. H. Wang, light trap.

Description. Male imago (n = 4). Total length 6.05–6.78 mm. Wing length 3.88–5.25 mm. Total length/wing length 1.29–1.56. Coloration. Antenna dark brown. Legs brown to dark brown. Thorax and abdomen dark brown to black.

Head. Antenna with 13 flagellomeres. AR 3.19–3. 48. Ultimate flagellomere 1030–1390 µm long. Subapical seta of terminal antennal flagellomere length 25.0–32.5 µm. Inner verticals 5–7. Postorbitals 12–19. Clypeus with 5–11 setae. Palpomere lengths (in µm): 50.0–70.0; 87.5–105.0; 192.5–280.0; 200.0–280.0; 200.0–292.5. Head width/palp length: 0.72–0.90.

Wing. Anal lobe developed. VR 2.80–4.00. Costal extension 100–150 µm long. R with 8–13 setae. R1 with 9– 14 setae. Squama with 80–82 setae.

Thorax. Antepronotal lobes developed. Antepronotum with 8–15 lateral setae. Dorsocentrals 17–24; prealars 11–24. Scutellum with 30–67 setae.

Legs. Spur of fore tibia 112.5–137.5 µm long; spurs of mid tibia 67.5–82.5 µm and 67.5–82.5 µm long; spurs of hind tibia 70.0–77.5 µm and 112.5–132.5 µm long. Hind tibial comb with 11–18 spines. Front without pseudospur; middle ta1 with 9–13 pseudospurs, ta2 with 2–3 pseudospurs; hind ta1 with 8–14 pseudospurs, ta2 with 2–4 pseudospurs. Lengths (in µm) and proportions of legs as in Table 1 .

Hypopygium ( Fig. 9 ). Anal point spiniform, 47–60 µm long. Tergite IX 150–175 µm long, with 14–35 setae. Laterosernite IX with 18–43 setae. Transverse sternapodeme 220.0–214.5 µm long. Aedeagal lobe in distal part shaped like a golf-club. Phallapodeme 187.5–215.0 µm long. Gonocoxite 287.5–447.5 µm long. Superior volsella small, rounded, with microtrichia. Median volsella spiniferous. Inferior volsella not apparent. Gonostylus 175–215 µm long, widest in about middle and narrowing towards apex with small megaseta. HR 1.64–2.23.

Pupa (n = 1). Total length 6.10 mm. Exuviae yellow.

Cephalothorax ( Figs. 5, 8 ). Frontal setae 360, 370 µm long. Frontal tubercles round. Ocular field with 320 µm long vertical. Thoracic horn absent. Anterior precorneal setae 60 µm long; median setae ( Fig. 8 , 16) strong, 260 µm long; posterior setae broken. Dorsocentrals 3, Dc1 200 µm long, Dc2 100 µm long, Dc3 113 µm long. Prealar 183 µm long.

Abdomen ( Figs. 6, 7 ). Tergite I without shagreen; tergite II with two rows of shagreen; tergites III-VIII covered by square shagreen. Tergal conjunctive I/II without hooklets, tergal conjunctive II/III with hooklets; tergal conjunctives III/IV-VII/VIII hooklets near central half of the segment, posterior spines; tergal conjunctive VIII/IX without hooklets, with posterior spines. Tergites I-VII with 5 D setae; VIII with 1 D seta. Segment I with 2 L setae, L1 simple, L2 2 branched; segment II-VIII with 4 L setae, excepting L 2 in segment IV and L 3 in segment VI simple, all L setae 3–8 branched. Anal lobe with two patches of shagreen at base, 470 µm long and 425 µm wide at base, with 3 equal anal macrosetae 350µm long, small and triangular tubercle present, 100 µm long and 80 µm wide at base. Anal lobe with fringe hair-like, numerous. Genital sac subequal in length to anal lobe.

Fourth instar larva (n = 4). Total length 6.25–10.00 mm. Head capsule light brown. Body light yellow.

Head. ( Figs. 1–4 ) Antenna ( Fig. 2 ) with 5 flagellomeres. Lengths antennal segments (µm): 82.5; 20.0–22.5; 7.5–10.0; 2.5; 5.0. AR 2.06–2.36. Basal antenna segment 27.5–30.0 µm wide; ring organ close to the base. Accessory blade 27.5–32.5 µm long. Premandible 100.0–107.5 µm long, with 1 apical tooth and 4 inner tooth. Mandible ( Fig. 3 ) 190.0–220.0 µm long with 1 apical tooth and 4 inner tooth. Third and fourth inner tooth wider and bigger than remaining. Pecten mandibularis brush–like. Mentum ( Fig. 4 ) dark brown, with 7 pairs of lateral teeth, almost entirely covered by ventromental plates. Ventromental plates 160.0–175.0 µm wide, 97.5–112.5 µm high. Postmentum 162.5–202.5 µm long.

Abdomen. Posterior parapods length/width: 270–490 µm/240–270 µm, apical with 11–15 branches. Procerus yellow, 15.0–25.0 µm high, 22.5–30.0 µm wide, with 7 long anal setae and 2 subapical setae. Supraanal setae 117.5–275.0 µm. Anal tubules shorter than posterior parapods.

Remarks. In the adult males from China most characteristics agree with the description of Markarcheko (1994) and other workers. In Markarcheko (1994), the superior volsella should be change to aedeagal lobe which in distal part like a golf-club. In this species, small and rounded superior volsella, with no apparent inferior volsella. The larva and pupal stage of the species are described for the first time. S. macrocera Serra-Tosio and S. takatensis (Tokunaga) and can easily be distinguished from others known pupae by the characters as following: anterior thoracic setation strong; thoracic horn absent. While the lengths of dorsocentral setae in S. takatensis (Tokunaga) (200; 100; 113) are much longer than S. macrocera Serra-Tosio (138–150; 50–68; 65–100). Moreover, Pc2 is branched in S. takatensis (Tokunaga) but simple in S. macrocera Serra-Tosio. Larvae of S. takatensis (Tokunaga) is easily recognized by the form of inner teeth of mandible (third and fourth inner tooth wider and bigger than remaining) and high AR (2.06–2.36).

Distribution. China (Palaearctic China: Liaoning Province; Tianjin City). Korea; Japan; Russia (Far East).

Figures

FIGURES 1 – 9. Sympotthastia takatensis (Tokunaga). Larvae. 1 — head; 2 — antenna; 3 — mandible; 4 — mentum. Pupae. 5 — frontal apotome; 6 — tergites I-VII; 7 — tergite VIII and anal lobe; 8 — thorax, lateral view. Male. 9 — genitalia.

Tables

TABLE 1. Lengths (in µm) and proportions of legs of Sympotthastia takatensis (Tokunaga) (n = 4).

	P1	P2	P3
fe	1025–1625	1100–1700	1325–2150
ti	1100–1875	1150–1850	1450–2400
ta1	925–1400	625–875	1025–1350
ta2	925–1400	350–525	550–700
ta3	325–500	275–400	350–470
ta4	175–300	150–225	175–250
ta5	175–225	150–175	175–200
LR	0.72–0.91	0.47–0.54	0.56–0.71
BR	3.27–5.26	3.82–5.58	3.39–6.11
SV	2.13–2.64	3.68–4.12	2.78–3.37
BV	2.60–2.92	2.93–3.45	2.82–3.63