Ablabesmyia (Ablabesmyia) amamisimplex Sasa

Niitsuma, Hiromi, 2013, Revision of the Japanese Ablabesmyia (Diptera: Chironomidae: Tanypodinae), with descriptions of three new species, Zootaxa 3664 (4), pp. 479-504 : 487-492

Ablabesmyia (Ablabesmyia) amamisimplex Sasa

( Figs 26–38 )

Ablabesmyia amamisimplex Sasa, 1990: 134 .

Ablabesmyia monilis: Sasa 1990: 135 ; Sasa & Okazawa 1991: 65; Sasa & Okazawa 1992: 208 partim; Sasa et al. 1998: 126 partim. [nec Linnaeus, 1758]

Ablabesmyia longistyla: Sasa et al. 1998: 125 partim; Kobayashi & Kubota 2002: 324 partim; Niitsuma 2005: 1053 fig. 16.10– 15. [nec Fittkau, 1962]

Material examined. Holotype of Ablabesmyia amamisimplex : male (NSMT-I-Dip4693), labelled, “No. 179: 59”, JAPAN: Kagoshima, Amami Island, Yakkachi River, 18.iii.1989 (adult emerged 10.iv.1989). Non-types. JAPAN: Kagoshima, Amami Island, Yakkachi River, 1 male (NSMT), labelled, “ Ablabesmyia monilis No. 179: 58”, 18.iii.1989 (adult emerged 14.iv.1989); Okinawa, Okinawa Island, Genga River, 3 males (NSMT), labelled respectively, “ Ablabesmyia monilis No. 174: 88–90”, 27.xi.1989; Toyama, Joganji River, 3 males (NSMT), labelled respectively, “ Ablabesmyia monilis No. 217: 48–50”, 9.viii.1990; Kochi, Nakamura, Shimano River, 1 male (NSMT), labelled, “ Ablabesmyia monilis No. 358: 2”, 25.iv.1998; Toyama, Toga, Momose River, 1male (NSMT), labelled, “ Ablabesmyia monilis No. 188: 1”, 11.ix.1990; Kochi, Nakamura, 1 male (NSMT), labelled, “ Ablabesmyia longistyla No. 360: 44”, 26.iv.1998; Fukushima, Hirono, Asami River, 1 male with pupal exuviae (SUM-IC-T0411), 15.viii.2001 (adult emerged 26.viii.2001); as previous except 3 males with 2 pupal exuviae (SUM-IC-T0412–T0414), 4.v.2005 (adults emerged 15–30.v.2005); as previous except 1 male with pupal exuviae (SUM-IC-T0415), 15.viii.2009 (adult emerged 18.viii.2009); Fukushima, Iwaki, Shiraiwa, 1 male with pupal exuviae (SUM-IC-T0416), 3.i.1990 (adult emerged 26.ii.1990); Iwaki, Yaguki, 5 males with 5 pupal and 2 larval exuviae (SUM-IC-T0417–T0421), and 2 females with 2 pupal and 1 larval exuviae (SUM-IC-T0422, T0423), 15.viii.2009 (adults emerged 21–30.viii.2009); as previous except 3 males with 2 pupa and 1 larval exuviae (SUM- IC-T0424–T0426), 2.i.2010 (adults emerged 15–28.i.2010); as previous except 4 males with 4 pupal and 4 larval exuviae (SUM-IC-T0427–T0430), 15.viii.2010 (adults emerged 2–5.ix.2010); as previous except 2 males with 2 pupal and 2 larval exuviae (SUM-IC-T0431, T0432), 15.viii.2011 (adults emerged 20 and 27.viii.2011); Kanagawa, Kiyokawa, Miyagase, 6 males with 6 pupal exuviae (SUM-IC-T0433–T0438), and 4 females with 4 pupal exuviae (SUM-IC-T0439–T0442), 14.vi.1998 (adults emerged 19.vi.–1.vii.1998); Yamanashi, Nagasaka, 3 males with 3 pupal exuviae (SUM-IC-T0443–T0445), 13.ix.1999 (adults emerged 20–22.ix.1999); Shizuoka, Suruga-ku, Nagasawa River, 1 female with pupal and larval exuviae (SUM-IC-T0446), 8.x.1997 (adult emerged 15.x.1997); Shizuoka, Fujieda, Forest Park Fujieda, 1 male with pupal exuviae (SUM-IC-T0447), and 1 female with pupal exuviae (SUM-IC-T0448), 9.vi.1999 (adults emerged 15.vi.1999); Gifu, Mino, Suhara, Nagara River, 1 male with pupal exuviae (SUM-IC-T0449), and 1 female with pupal exuviae (SUM-IC-T0450), 12.ix.2009 (adults emerged 26–27.ix.2009).

Description. Male (n = 42). Body length 2.7–4.0, 3.1 (31) mm.

Colouration. Thorax yellow with brown scutal vittae, anepisternum II, preepisternum and postnotum. All abdominal tergites pale yellow, occasionally tergites VI–VIII darkened anteriorly. Wing ( Fig. 26 ) darkened on humeral cross-vein, RM, FCu, and on costal vein and surrounding areas at apices of R1, R2 and R4+5. Subbasal and median bands on foretibia located 0.78–0.81 and 0.38–0.43, respectively, from apex of tibia.

Head. Temporals 19–32, 26 (28), multiserial except uniserial postorbitals. AR 1.6–1.9. Clypeus trapezoid with 26–44, 34 (31) setae. Lengths of palpomeres 1–5 (μm): 40–55, 49 (27); 85–125, 98 (27); 120–175, 143 (27); 90– 130, 108 (27); 225–325, 265 (27). Pm4 0.70–0.84 times as long as Pm3; Pm5 2.3–2.7 times as long as Pm4.

Thorax. Aps 5–15, 9 (30); Ac 45–74, 57 (27), biserial between median scutal vittae, diverging posteriorly; Dc 14–27, 19 (31), uniserial, occasionally biserial anteriorly; H 6–15, 10 (31); Pa 12–26, 18 (31); Su 1–2, 1 (30); Scts 25–43, 32 (31).

Wing. Length 1.8–2.7, 2.1 (31) mm, Squama with 25–43, 33 (29) setae. VR 0.82–0.91.

Legs. Spur on foretibia 35–58, 46 (31) μm long with 6–8, 7 (27) lateral teeth. Spurs on mid tibia 50–70, 57 (30) and 23–43, 29 (30) μm long, with 6–8, 7 (16) and 4–6, 5 (23) lateral teeth, respectively; inner spur 1.6–2.3 times as long as outer spur. Spurs on hind tibia 58–85, 66 (30) and 23–38, 28 (29) μm long, with 4–6, 5 (10) and 2–5, 3 (21) lateral teeth, respectively; inner spur 2.0–3.0 times as long as outer spur; hind tibial comb consisting of 5–7, 6 (31) bristles. All legs with subapical pseudospurs on ta1–3; claws pointed or weakly bifid apically, each with 2 (31) long and 2–3, 3 (31) short basoventral spines. Lengths and proportions of leg segments as in Table 3 .

Hypopygium ( Fig. 27 ). Tergite IX with 2–12, 4 (31) lateral setae. Gonocoxite 135–188, 151 (31) μm long; dorsal lobe 20–28, 24 (31) μm long, apically curved outwards with setal fringe; blade 30–45, 36 (31) μm long, distally curved and pointed; lateral lobe 25–35, 30 (26) μm long, well defined, lanceolate with weak serrations; lateral filaments not evident ( Fig. 28 ). Gonostylus 138–195, 156 (31) μm long, 0.95–1.1 times as long as gonocoxite; megaseta apically expanded.

Female (n = 9). Body length 2.0–2.2, 2.1 (7) mm.

Colouration. Similar to male. Subbasal and median bands on foretibia located 0.75–0.80 and 0.41–0.43, respectively, from apex of tibia. Seminal capsule brown on oral 2/3.

Head. Temporals 26–38, 32. Antenna with terminal flagellomere almost as long as preceding 3 flagellomeres together; AR 0.26–0.31. Clypeus with 43–62, 50 setae. Lengths of palpomeres 1–5 (μm): 45–55, 50 (7); 80–110, 91 (7); 133–158, 141 (7); 100–118, 109 (7); 225–290, 258 (7). Pm4 0.74–0.80 times as long as Pm3; Pm5 2.2–2.5 times as long as Pm4.

Thorax. Aps 8–16, 10; Ac 51–77, 65 (8); Dc 21–28, 24; H 15–23, 19; Pa 23–32, 28; Su 1; Scts 37–52, 42 (7).

Wing. Length 1.5–2.2, 1.8 mm. Squama with 24–45, 36 (7) setae. VR 0.83–0.90.

Legs. Spur on foretibia 43–53, 46 (8) μm long with 6–7, 7 (4) lateral teeth. Spurs on mid tibia 50–60, 54 and 23–35, 27 (8) μm long, with 7 (4) and 5–6, 5 (7) lateral teeth, respectively; inner spur 1.6–2.3 times as long as outer spur. Spurs on hind tibia 58–70, 62 μm long and 23–33, 25 (8) μm long, with 6 (1) and 3–5, 4 (6) lateral teeth, respectively; inner spur 1.9–2.9 times as long as outer spur; hind tibial comb consisting of 5–6, 6 bristles. All legs with subapical pseudospurs on ta1–3; hind leg with 3–7, 5 sensilla chaetica on basal 0.41–0.51 of ta1. Lengths and proportions of leg segments as in Table 3 .

Genitalia ( Fig. 29 ). Notum 95–130, 117 (7) μm long and almost twice as long as ramus. Seminal capsule oval, 58–63, 60 (3) μm long and 53–55, 54 (3) μm wide. Segment X with 1–5, 3 (8) fine setae on each side.

Pupa (n = 38). Body length 3.5–4.9, 3.9 mm.

Colouration. Exuviae pale brown and pigmentation pattern distinct. Wing sheath brown along margin and veins. Abdominal tergites II–VI pale brown each with dark transverse band along posterior margin somewhat interrupted submedially, and pair of dark vertical medial bands or pair of dark patches anteromedially, occasionally tergites V and VI without dark markings ( Fig. 30 a, b).

Cephalothorax. Thoracic horn ( Fig. 31 ) 320–450, 349 (33) μm long and 1.6–2.1 times as long as broadest width; apex of aeropyle tube club-shaped ( Fig. 32 a, b). Thoracic comb composed of 9–15, 11 teeth with rounded apices.

Abdomen ( Fig. 33 ). Tergal shagreen ( Fig. 34 ) consisting of slightly arched, transverse rows of 2–4 spinules. LS1-seta on A.VII located 0.38–0.49 from anterior margin, and on A.VIII located 0.22–0.33. Anal lobe 345–460, 374 μm long, 2.2–2.9 times as long as wide; anterior and posterior anal macrosetae located 0.54–0.59 and 0.60– 0.65, respectively, from anterior margin; male genital sac 0.74–0.81 as long as anal lobe.

Fourth instar larva (n = 11).

Colouration. Head yellow with dark postoccipital margin; body entirely yellow when live.

Head. Length 737–828, 768 (3) μm; cephalic index 0.56–0.59. Ventral cephalic seta S10 anterolateral or directly lateral to sensory pore; lines S9-VP and S10-VP making obtuse angle ( Fig. 35 ). Antenna 0.54 (1) times as long as head capsule; lengths of segments 1–4 (μm): 315–395, 332 (10); 75–83, 78 (8); 5 (8); 5 (8). AR 3.6–3.8. First antennal segment 14.0–16.5 times as long as basal width, with ring organ located 0.63–0.65 from base; blade 80–85, 83 (6) μm long, reaching middle of 3rd segment; accessory blade 79–85, 82 (6) μm long. Second antennal segment 15.0–16.5 times as long as basal width; style 8–10, 9 (6) μm long, reaching middle of 4th segment; peg sensillum 3 (8) μm long. Mandible 120–155, 132 (9) μm long and 0.30–0.34 times as long as antenna; basal tooth with tip directed apically; accessory tooth large, partly overlying base of seta subdentalis. Basal segment of maxillary palp ( Fig. 36 ) subdivided into 1 long (p1) and 3 short parts (p2–4), 80–93, 87 (9) μm in total length, and 6.0–7.1 times as long as basal width; p2 0.4–0.5 times as long as P1, and 1.0–1.5 times as long as p3. Ligula ( Fig. 37 ) 93–105, 98 (8) μm long, 1.8–2.1 times as long as toothed width, with basal granulose area occupying 0.23–0.28 of total length; middle tooth 1.5–2.0 times as long as wide. Paraligula bifid and 45–50, 48 (8) μm long; fork located 0.50–0.55 from base; outer spine 2.3–3.2 times as long as inner spine. Pecten hypopharyngis with 17–20, 18 (6) teeth.

Body. Procercus 2.9–3.2 times as long as basal width; both lateral setae located 0.35–0.39 and 0.65–0.73, respectively, from base. Posterior parapod with 16 claws including 1 brown and 2 dark brown claws; smallest claw gently curved, and large claws finely pectinate along inner and outer margins ( Fig. 38 ).

Remarks. Sasa (1990) described Ablabesmyia amamisimplex , based only on the holotype male reared in the laboratory, and noted (p. 135), “the present species is unusual in that legs and abdomen are entirely pale.” After reexamination of the holotype, it has become evident that the specimen has tibiae banded subbasally, centrally and apically, wings with two distinct markings along the costal margin, and an aedeagal complex with a dorsal lobe fringed apically, a blade curved distinctly, and a lateral lobe damaged by the slide-mounting preparation. The aforementioned features fit those of my specimens belonging to Ablabesmyia s. str. The Japanese species A. amamisimplex is valid as a member of this subgenus.

Judging from the adult morphology, A. (A.) amamisimplex belongs to the A. (A.) simpsoni species group. Based on the larva, however, the species does not belong to any group defined by Roback (1985), since the basal segment of maxillary palp is subdivided into four parts.

The male of A. (A.) amamisimplex is most similar to that of A. (A.) longistyla Fittkau , in the dorsal lobe with an apical setal fringe and the aedeagal blade pointed apically, but the former differs in the wing with two dark spots along the costal margin, and the aedeagal blade curved distinctly. In A. (A.) longistyla , the wing has three dark spots, one located at the end of R1, and two faint ones located at ends of R3 and R4+5, according to Bilyj (pers. comm.), who has examined the type specimen deposited in the Zoologische Staatssammlung München (ZSM), Germany. The aedeagal complex is armed with an almost straight blade, according to Fittkau (1962, fig. 396), Pinder (1978, fig. 17C), Cranston & Judd (1989, fig. 7) and Panis et al. (1992, fig. 1). Kobayashi & Kubota (2002) ignored the morphological difference between the aedeagal blades of the two species.

The pupal abdominal tergite IV has longitudinal dark bands sublaterally in A. (A.) longistyla (Langton 1984: 48) , but not in A. (A.) amamisimplex . In the larva, the basal segment of the maxillary palp is subdivided into four parts in A. (A.) amamisimplex , while five or six parts in A. (A.) longistyla (Laville 1971, Rieradevall & Brooks 2001, Vallenduuk & Pillot 2007).

Figures

FIGURES 26 – 29. Ablabesmyia (Ablabesmyia) amamisimplex Sasa, male (26 – 28) and female (29). 26, Wing; 27, hypopygium, dorsal view; 28, aedeagal complex, dorsal view; 29, genitalia, ventral view.

FIGURES 30 – 38. Ablabesmyia (Ablabesmyia) amamisimplex Sasa, pupa (30 – 34) and larva (35 – 38). 30 a, b, Abdominal segment IV, dorsal view, showing variation of pigmentation pattern; 31, thoracic horn; 32 a, b, apex of thoracic horn with apical nipple, showing variation of aeropyle tube; 33, abdominal segments VII – IX, dorsal view, all dorsal and left lateral setae omitted; 34, shagreen on posteromedial part of abdominal tergite IV; 35, arrangement of ventral cephalic setae and sensory pore; 36, maxillary palp with apical stylets; 37, ligula and paraligula, left paraligula omitted; 38, medium- and small-sized claws of posterior parapod.

Tables

TABLE 3. Lengths (μm) and proportions of legs of Ablabesmyia (Ablabesmyia) amamisimplex Sasa, male (n = 31) and female (n = 9).

Male		fe	ti	ta1	ta2	ta3	ta4	ta5	LR	BR
	P1	646–899 715	768–1040 835	586–828 658	394–586 447	282–404 324	182–263 204	111–162 124	0.75–0.84	3.0–4.2
	P2	677–1020 794	657–960 746	576–788 642	313–455 363	232–333 265	152–222 175	101–141 114	0.81–0.98	4.5–6.9
	P3	646–939 727	869–1252 978	747–1061 839	394–596 455	293–455 337	192–283 217	111–152 121	0.82–0.91	5.0–6.7
Female
	P1	586–768 659	646–838 726	545–697 596	323–444 361	232–323 265	162–202 177	101–121 110	0.79–0.84
	P2	687–889 766	657–818 722	576–667 609	303–394 336	212–273 242	141–182 160	101–121 108	0.81–0.88
	P3	616–808 687	788–1030 878	697–859 763	374–495 420	273–374 316	172–232 199	101–131 114	0.83–0.91