Ablabesmyia (Ablabesmyia) jogancornua Sasa et Okazawa

Niitsuma, Hiromi, 2013, Revision of the Japanese Ablabesmyia (Diptera: Chironomidae: Tanypodinae), with descriptions of three new species, Zootaxa 3664 (4), pp. 479-504 : 492-496

Ablabesmyia (Ablabesmyia) jogancornua Sasa et Okazawa

( Figs 39–51 )

Ablabesmyia jogancornua Sasa et Okazawa, 1991: 64 .

Ablabesmyia monilis: 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. [nec Fittkau, 1962]

Material examined. Holotype of Ablabesmyia jogancornua : male (NSMT-I-Dip4827), labelled, “No. 271: 100”, JAPAN: Toyama, Wada River, 9.viii.1990 (adult emerged 15.viii.1990). Non-types. JAPAN: Toyama, Toga, Toga River, 1 male (NSMT), labelled, “ Ablabesmyia monilis No. 188: 2”, 11.ix.1990; Kochi, Nakamura, 1 male (NSMT), labelled, “ Ablabesmyia longistyla No. 360: 24”, 26.iv.1998; Kochi, Hiromi, 1 male (NSMT), labelled, “ Ablabesmyia monilis No. 359: 28”, 27.iv.1998; Fukushima, Hirono, Asami River, 1 male with pupal exuviae (SUM-IC-T0451), 1.i.2003 (adult emerged 18.i.2003); as previous except 1 male with pupal exuviae (SUM-IC- T0452), 4.v.2005 (adult emerged 9.v.2005); as previous except 2 males with 2 pupal exuviae (SUM-IC-T0453, T0454), 5.v.2005 (adult emerged 19 and 21.v.2005); as previous except 1 male with pupal exuviae (SUM-IC- T0455), 15.viii.2009 (adult emerged 27.viii.2009); Fukushima, Iwaki, Yaguki, 3 males with 3 pupal exuviae (SUM-IC-T0456–T0458), and 1 female with pupal exuviae (SUM-IC-T0459), 15.viii.2009 (adults emerged 25– 30.viii.2009); as previous except 3 males with 2 pupal exuviae (SUM-IC-T0460–T0462), and 2 females with 2 pupal exuviae (SUM-IC-T0463, T0464), 15.viii.2010 (adults emerged 8–10.viii.2010); as previous except 1 male with pupal exuviae (SUM-IC-T0465), and 1 female with pupal exuviae (SUM-IC-T0466), 15.viii.2011 (adults emerged 19 and 28.viii.2011); Kanagawa, Kiyokawa, Miyagase, 1 male with pupal exuviae (SUM-IC-T0467), 2 female with 2 pupal and 1 larval exuviae (SUM-IC-T0468, T0469), and 1 pupa with larval exuviae (SUM-IC- T0470), 14.vi.1998 (adults emerged 20.vi.–3.vii.1998); as previous except 1 male with pupal exuviae (SUM-IC- T0471), 18.x.1998 (adult emerged 22.x.1998); as previous except 1 male with pupal exuviae (SUM-IC-T0472), 13.vi.1999 (adult emerged 25.vi.1999); Shizuoka, Fujinomiya, Shibakawa, Inase River, 1 male with pupal exuviae (SUM-IC-T0473), 15.vii.1991 (adult emerged 20.vii.1991); Shizuoka, Shimizu-ku, Yanbara, 1 male with pupal exuviae (SUM-IC-T0474), 21.vii.1999 (adult emerged 27.vii.1999); Shizuoka, Aoi-ku,. Yokosawa, Abe River, 1 female with pupal and larval exuviae (SUM-IC-T0475), 29.viii.1999 (adult emerged 5.ix.1999).

Description. Male (n = 21). Body length 2.6–3.7, 3.2 (17) mm.

Colouration. Thorax yellow with brown scutal vittae, anepisternum II, preepisternum and postnotum. Abdomen pale yellow, occasionally tergites VI–VIII darkened anteriorly. Wing ( Fig. 39 ) darkened on humeral cross-vein, RM, FCu, and on costal vein and surrounding areas at apices of R1, R2, R3 and R4+5. Subbasal and median bands on foretibia located 0.76–0.82 and 0.36–0.43, respectively, from apex of tibia.

Head. Temporals 24–36, 31 (15), multiserial except uniserial postorbitals. AR 1.5–1.9. Clypeus trapezoid with 36–48, 42 (14) setae. Lengths of palpomeres 1–5 (μm): 40–63, 50, (12); 83–108, 98 (12); 130–160, 146 (12); 100– 130, 114 (12); 225–320, 261 (12). Pm4 0.71–0.83 times as long as Pm3; Pm5 2.2–2.6 times as long as Pm4.

Thorax. Aps 7–16, 11 (17); Ac 51–78, 62 (13), biserial between median scutal vittae, diverging posteriorly; Dc 19–29, 24 (17), uniserial, but biserial anteriorly; H 10–20, 13 (17); Pa 17–28, 22 (17); Su 1–2, 1 (16); Scts 29–55, 41 (16).

Wing. Length 1.7–2.6, 2.1 (16) mm. Squama with 30–51, 42 (14) setae. VR 0.86–0.91.

Legs. Spur on foretibia 43–58, 49 (17) μm long with 6–8, 7 (15) lateral teeth. Spurs on mid tibia 53–68, 60 (17) and 28–40, 33 (17) μm long, with 6–8, 7 (8) and 4–6, 5 (12) lateral teeth, respectively; inner spur 1.7–2.1 times as long as outer spur. Spurs on hind tibia 55–73, 63 (17) and 25–38, 30 (17) μm long, with 5–6, 6 (8) and 2–4, 3 (11) lateral teeth, respectively; inner spur 1.7–2.4 times as long as outer spur; hind tibial comb consisting of 5–7, 6 (15) bristles. All legs with subapical pseudospurs on ta1–3; claws pointed or weakly bifid apically, each with 2 (17) long and 2–4, 3 (17) short basoventral spines. Lengths and proportions of leg segments as in Table 4 .

Hypopygium. Tergite IX with 0–5, 2 (17) lateral setae. Gonocoxite 143–190, 163 (17) μm long; dorsal lobe 33– 43, 37 (17) μm long, with apical setal fringe; blade 48–58, 53 (17) μm long, slightly curved, with apex pointed; lateral lobe 53–65, 57 (17) μm long, elongate and dentate along inner margin; lateral filaments not evident ( Fig. 40 ). Gonostylus 133–178, 151 (17) μm long, 0.89–0.99 times as long as gonocoxite, with megaseta expanded apically.

Female (n = 7). Body length 1.9–2.2, 2.0 (5) mm.

Colouration. Similar to male. Subbasal and median bands on foretibia located 0.78–0.80 and 0.38–0.43, respectively, from apex of tibia. Seminal capsule brown on oral 1/2–2/3.

Head. Temporals 25–34, 30. Antenna with terminal flagellomere almost as long as or somewhat longer than preceding 3 flagellomeres together; AR 0.31–0.34. Clypeus with 45–62, 53 setae. Lengths of palpomeres 1–5 (μm): 45–60, 51 (6); 88–105, 98 (6); 135–163, 144 (6); 105–133, 117 (6); 220–295, 256 (6). Pm4 0.75–0.85 times as long as Pm3; Pm5 2.1–2.4 times as long as Pm4.

Thorax. Aps 8–18, 12; Ac 50–70, 61; Dc 19–33, 23; H 14–29, 20; Pa 22–36, 29; Su 1 (6); Scts 33–54, 44.

Wing. Length 1.7–2.0, 1.8 mm. Squama with 25–42, 37 (5) setae. VR 0.85–0.91.

Legs. Spur on foretibia 40–48, 44 μm long with 6–7, 6 (6) lateral teeth. Spurs on mid tibia 53–60, 56 and 30– 38, 34 μm long, with 7–8 (2) and 4–6, 5 (6) lateral teeth, respectively; inner spur 1.6–1.8 times as long as outer spur. Spurs on hind tibia 55–65, 60 (6) and 25–35, 31 (6) μm long, with 6–7, 7 (4) and 2–3, 3 (4) lateral teeth, respectively; inner spur 1.8–2.2 times as long as outer spur; hind tibial comb consisting of 6–7, 6 bristles. All legs with subapical pseudospurs on ta1–3; hind leg with 3–6, 4 sensilla chaetica on basal 0.40–0.53 of ta1. Lengths and proportions of leg segments as in Table 4 .

Genitalia ( Fig. 41 ). Gonapophysis IX well developed; notum 100–128, 116 (4) μm long, and almost twice as long as ramus. Seminal capsule oval, 45–58, 52 (6) μm long and 40–50, 47 (6) μm wide. Segment X with 0–3, 2 (4) fine setae.

Pupa (n = 24). Body length 3.6–4.8, 4.1 (23) mm.

Colouration. Exuviae pale brown with distinct pigmentation pattern. Wing sheath broadly infuscated along margin and veins. Abdominal tergites II–VII each with pair of dark patches anteromedially, longitudinal dark bands along rows of lateral muscle marks, and transverse dark band along posterior margin; occasionally tergites more extensively darkened ( Fig. 42 a, b).

Cephalothorax. Thoracic horn 310–435, 371 (22) μm long and 1.8–2.2 times as long as broadest width; apex of aeropyle tube club-shaped ( Fig. 43 ). Thoracic comb composed of 9–16, 11 (23) teeth with round apices.

Abdomen ( Fig. 44 ). Tergal shagreen ( Fig. 45 ) consisting of slightly arched, transverse rows of several spinules. LS1-seta on A.VII located 0.45–0.51 from anterior margin, and on A.VIII located 0.27–0.38. Anal lobe 345–460, 383 (23) μm long and 2.2–2.6 times as long as wide; anterior and posterior anal macrosetae located 0.48–0.57 and 0.58–0.64, respectively, from anterior margin; male genital sac 0.78–0.83 as long as anal lobe.

Fourth instar larva (n = 3).

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

Head. Lines S9-VP and S10-VP making obtuse angle ( Fig. 46 ). Lengths of antennal segments 1–4 (μm): 313– 340, 329; 73–75 (2); 5 (2); 4 (2). AR 3.6–3.8. First antennal segment 13.4–13.9 times as long as basal width, with ring organ located 0.60–0.63 from base; blade 78 (2) μm long, reaching middle of 3rd segment; accessory blade 75 (2) μm long. Second antennal segment ( Fig. 47 ) 14.5–15.0 times as long as basal width; style 8 (1) μm long, reaching middle of 4th segment; peg sensillum 3 (2) μm long. Mandible ( Fig. 48 ) 143–145, 144 μm long, 0.34– 0.37 times as long as antenna, with basal tooth directed apically and with distinct accessory tooth. Basal segment of maxillary palp ( Fig. 49 ) subdivided into 1 long (p1) and 3 short parts (p2–4), 73–85, 78 μm in total length, and 5.7– 6.0 times as long as basal width; p2 0.4 times as long as p1, and 1.7–2.0 times as long as P3. Ligula ( Fig. 50 ) 100– 103, 101 μm long, 1.8–2.0 times as long as toothed width, with basal granulose area occupying 0.23–0.25 of total length. Paraligula bifid and 50 μm long; fork located 0.45–0.55 from base; outer spine 2.8–3.6 times as long as inner spine. Pecten hypopharyngis with 17–21, 19 teeth.

Body. Procercus 3.2–3.3 times as long as basal width; both lateral setae located 0.35–0.36 and 0.65–0.69, respectively, from base. Posterior parapod with 13 pale and 3 brown claws; smallest claw evenly curved, and large claws finely pectinate along inner and outer margins ( Fig. 51 ).

Remarks. Sasa & Okazawa (1991) described Ablabesmyia jogancornua , based only on a single male specimen, and noted (p. 65), “Gonocoxite with 3 pairs of basal lobes, the dorsal lobe brush-like and short; the middle lobe 1.5 times as long as the ventral lobe, horn-like and simple (left) or with apical brush (right); the ventral lobe also horn-like, twice as long as the dorsal lobe, and with apical brush.” Reexamination of the holotype has revealed that the dorsal, the middle and the ventral lobes are interpreted as the dorsal lobe, the aedeagal blade and the lateral lobe, respectively, as defined by Roback (1971), and that the aedeagal blades have no brush apically, and that the lateral lobe is elongate with weak serrations along the inner margin.

This species most resembles the species illustrated by Kobayashi & Kubota (2002, fig. 13) under the name of A. (A.) longistyla , in the features of the aedeagal complex, especially the evident lateral lobe. However, real A. (A.) longistyla differs from A. jogancornua in the straight aedeagal blade and the inconspicuous lateral lobe (see Fittkau 1962, fig. 396; Pinder 1978, fig. 81A; Cranston & Judd 1989, figs 6, 7). Kobayashi & Kubota (l. c.) might have a poor understanding of the structure of the aedeagal complex. Thus the species is valid as a member of Ablabesmyia s. str.

Ablabesmyia (A.) jogancornua shares several features with members of the A. (A.) simpsoni species group. The adult aedeagal complex has a fringed dorsal lobe and a more or less distinct lateral lobe, and in the larval posterior parapod the small claw is not curved sharply (Roback 1985). The species, however, do not belong to the A. (A.) simpsoni species group, because of the larval maxillary palp with a basal segment subdivided into four parts.

The adult male of A. (A.) jogancornua is similar to that of the North American species A. (A.) janta (Roback) in the aedeagal blade curved and pointed apically and the dentate lateral lobe. However these species are separable from one another. In A. (A.) jogancornua the lateral lobe has a dentate inner margin, whereas, in A. (A.) janta it is pectinate distally. The latter species belongs to the A. (A.) rhamphe species group (Roback 1985), and the larval maxillary palp has a basal segment subdivided into three parts.

Figures

FIGURES 39 – 41. Ablabesmyia (Ablabesmyia) jogancornua Sasa et Okazawa, male (39, 40) and female (41). 39, Wing; 40, aedeagal complex, dorsal view; 41, genitalia, ventral view.

FIGURES 42 – 51. Ablabesmyia (Ablabesmyia) jogancornua Sasa et Okazawa, pupa (42 – 45) and larva (46 – 51). 42 a, b, Abdominal segment IV, dorsal view, showing variation of pigmentation pattern; 43, apex of thoracic horn with apical nipple; 44, abdominal segments VII – IX, dorsal view, all dorsal and left lateral setae omitted; 45, shagreen on posteromedial part of abdominal tergite IV; 46, arrangement of ventral cephalic setae and sensory pore; 47, apex of antenna; 48, mandible; 49, maxillary palp with apical stylets; 50, ligula and paraligula, right paraligula omitted; 51, medium- and small-sized claws of posterior parapod.

Tables

TABLE 4. Lengths (μm) and proportions of legs of Ablabesmyia (Ablabesmyia) jogancornua Sasa et Okazawa, male (n = 16) and female (n = 7).

Male	fe	ti	ta1	ta2	ta3	ta4	ta5	LR	BR
	P1 626–889 763	687–1010 875	545–788 687 (15)	323–515 436 (15)	242–364 314 (15)	162–242 209 (15)	91–141 122 (15)	0.76–0.81	3.0–4.0
	P2 717–1030 869	636–990 822	515–717 617	273–414 355	222–313 266	152–212 184	101–131 116	0.72–0.81	4.7–6.9
	P3 646–909 775	788–1192 991	646–960 816 (15)	354–556 462 (15)	273–414 349 (15)	182–263 227 (15)	101–141 123 (15)	0.78–0.85	5.5–6.9
Female
	P1 636–788 682	717–899 778	556–687 613	313–414 359	242–313 264	162–212 185	101–121 111	0.76–0.82
	P2 727–919 807	687–879 760	545–636 581	283–364 315	202–263 231	141–182 162	91–111 104	0.72–0.79
	P3 667–818 716	828–1020 890	657–778 711	364–455 397	283–354 307	172–232 199	101–121 114	0.76–0.84