Ablabesmyia (Ablabesmyia) prorasha Kobayashi et Kubota

Niitsuma, Hiromi, 2013, Revision of the Japanese Ablabesmyia (Diptera: Chironomidae: Tanypodinae), with descriptions of three new species, Zootaxa 3664 (4), pp. 479-504 : 485-487

Ablabesmyia (Ablabesmyia) prorasha Kobayashi et Kubota

( Figs 16–25 )

Ablabesmyia monilis: Ree & Kim 1981: 180 ; Sasa & Suzuki 1997: 340. [nec Linnaeus, 1758] Ablabesmyia prorasha Kobayashi et Kubota, 2002: 323 .

Material examined. Non-type. JAPAN: Fukushima, Hirono, Asami River, 1 male with pupal and larval exuviae (SUM-IC-T0410), 5.viii.2001 (adult emerged 26.viii.2001).

Description. Male (n = 1). Body length 3.2 mm.

Colouration. Very similar to A. (A.) monilis , except abdomen entirely pale yellow. Wing ( Fig. 16 ) conspicuously 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 0.81 and 0.42, respectively, from apex of tibia.

Head. Temporals 32, multiserial except uniserial postorbitals. AR 1.8. Clypeus trapezoid with 40 setae. Lengths of palpomeres 1–5 (μm): 40, 95, 138, 100, 250.

Thorax. Aps 11; Ac 68, biserial between median scutal vittae; Dc 27, uniserial; H 7; Pa 18; Su 1; Scts 33.

Wing. Length 2.0 mm. Squama with 36 setae. VR 0.86.

Legs. Spur on foretibia 50 μm long with 9 lateral teeth. Spurs on mid tibia 58 and 35 μm long, with 8 and 4 lateral teeth, respectively. Spurs on hind tibia 63 and 30 μm long, with 7 and 4 lateral teeth, respectively; hind tibial comb consisting of 6 bristles. All legs with subapical pseudospurs on ta1–3; claws bifid or pointed apically, each with 2 long and 3 short basoventral spines. Lengths and proportions of leg segments as in Table 2 .

Hypopygium. Tergite IX without lateral setae. Gonocoxite 165 μm long; dorsal lobe 40 μm long, curved outwards, with apical fringe of short setae; blade 65 μm long, sinuate, parallel-sided, with apex rounded; lateral lobe not evident; lateral filaments well developed ( Fig. 17 ). Gonostylus 145 μm long with megaseta expanded apically.

Female. Unknown.

Pupa (n = 1). Body length 4.2 mm.

Colouration. Exuviae rather pale, but pigmentation pattern distinct. Wing sheath with margin and veins slightly infuscated. Abdominal tergites II–VI each with pair of faint dark patches anteromedially and narrow dark band along posterior margin ( Fig. 18 ).

Cephalothorax. Thoracic horn bulbous, 384 μm long and 1.9 times as long as broadest width; apical nipple crushed. Thoracic comb composed of 11 teeth.

Abdomen ( Fig. 19 ). Tergal shagreen ( Fig. 20 ) consisting of slightly arched, transverse rows of 2–3 spinules. LS1-seta on A.VII located 0.38 from anterior margin, and on A.VIII located 0.27. Anal lobe 385 μm long, 2.5 times as long as wide, outer margin spinulate; anterior and posterior anal macrosetae located 0.53 and 0.62, respectively, from anterior margin. Male genital sac 0.78 as long as anal lobe.

Fourth instar larva (n = 1).

Colouration. Head relatively pale yellow with dark postoccipital margin.

Head. Lines S9-VP and S10-VP making obtuse angle ( Fig. 21 ). Lengths of antennal segments 1–4 (μm): 320, 65, 5, 5 ( Fig. 22 ). AR 4.3. First antennal segment 12.8 times as long as basal width, with ring organ located 0.59 from base; blade 70 μm long, reaching middle of 3rd segment; accessory blade 71 μm long, slightly longer than blade. Second antennal segment 13.0 times as long as basal width; style 8 μm long, reaching middle of 4th segment; peg sensillum half as long as 3rd segment. Mandible 138 μm long, 0.35 times as long as antenna, with large basal tooth and accessory tooth. Basal segment of maxillary palp ( Fig. 23 ) subdivided into 3 parts (p1–3) in proportion of 12: 10: 3, 70 μm long in total length, and 4.7 times as long as basal width. Ligula ( Fig. 24 ) 103 μm long, 2.0 times as long as toothed width, with basal granulose area occupying 0.29 of total length; middle tooth 1.8 times as long as wide; inner lateral teeth orientated slightly inward; toothed margin only slightly concave. Paraligula bifid and 45 μm long; fork positioned 0.44 from base; outer spine 3.3 times as long as inner spine. Pecten hypopharyngis with 19 teeth.

Body. Procercus 3.1 times as long as basal width; both lateral setae located 0.39 and 0.66, respectively, from base. Posterior parapod with 16 claws including 1 slightly brown and 2 dark brown claws; smallest claw sharply bent with large basal expansion, and large claws finely pectinate along inner and outer margins ( Fig. 25 ).

Remarks. Ablabesmyia (A.) prorasha belongs to the A. (A.) monilis species group as defined by Roback (1985, table 1).

Kobayashi & Kubota (2002: 323) discussed similarities and differences between A. (A.) prorasha and the North American species A. (A.) rasha Roback. However , this species is morphologically much closer, in all life stages, to the North American A. (A.) basalis (Walley) , which Roback (1985) synonymized with A. (A.) monilis . However Saether (2011) has reestablished it as a valid species. The aedeagal complex in A. (A.) prorasha (Kobayashi & Kubota 2002, fig. 15) is very similar to that of A. (A.) basalis drawn by Roback (1971, figs 570, 607) and Saether (2011, fig. 8E, F).

Figures

FIGURES 16 – 25. Ablabesmyia (Ablabesmyia) prorasha Kobayashi et Kubota, male (16, 17), pupa (18 – 20) and larva (21 – 25). 16, Wing; 17, aedeagal complex, dorsal view; 18, abdominal segment IV, dorsal view, showing pigmentation pattern; 19, abdominal segments VII – IX, dorsal view, all dorsal and left lateral setae omitted; 20, shagreen on posteromedial part of abdominal tergite IV; 21, arrangement of ventral cephalic setae and sensory pore; 22, antenna; 23, maxillary palp with apical stylets; 24, ligula and paraligula, right paraligula omitted; 25, medium- and small-sized claws of posterior parapod.

Tables

TABLE 2. Lengths (μm) and proportions of legs of Ablabesmyia (Ablabesmyia) prorasha Kobayashi et Kubota, male (n = 1).

fe	ti	ta1	ta2	ta3	ta4	ta5	LR	BR
P1 737	838	677	404	293	202	121	0.81	3.2
P2 838	808	616	343	263	182	111	0.76	5.6
P3 768	960	798	465	354	222	126	0.83	5.6