Ascodipteron longiascus, Hastriter, 2007

Hastriter, Michael W., 2007, A review of Ascodipterinae (Diptera: Streblidae) of the Oriental and Australasian regions with a description of three new species of Ascodipteron Adensamer and a key to the subfamily, Zootaxa 1636 (1), pp. 1-32 : 11-13

Ascodipteron longiascus sp. nov.

( Figs. 4–5 )

Type material. Holotype, dealate female; China: Yunnan Province, Shweli River , ex. Hipposideros armiger ( AMNH #44993–44994 , # 45007–45008 ), 10 IV 1917, R. C. Andrews and E. Heller (Asiatic Expedition) (slide BM-1034D) ( BPBM) . Paratypes: 3 dealate females, same data as holotype (slides BM-1034A, C) ( BPBM) and (slide BM-1034B) ( MWH) .

Diagnosis. Distinguished from all other species of Ascodipteron by the combination of 1) a truncate dorsal margin on the gena, 2) the presence of only 3–4 VSS, and 3) the absence of spiniform setae on coxa 1.

Description. Head ( Figs. 4A–C ). Length and width of labial theca nearly equal; short-headed species. Posterior margin concave dorsad and convex ventrad. Anterior dorsal margin convex with two long setae to each side of midline; caniculi leading from each. About 30 short, non-pigmented peg-like setae on mediolateral dorsal surface of labial theca; ventral surface with same pattern and similar number of setae. Peg-like setae are identical to those on gena. Ventral surface with 14–16 thin setae confined to anterior apical area. Arista branching near apex. Width and length of lateral vertex subequal, with 30–35 papilla-like setae. Gena very broad and truncate dorsally; 40+ non-pigmented, sharp setae on dorsal half. Thorax ( Figs. 4A , 5A–E ). Scutum with lateral pattern of papilla-like setae (similar to lateral vertices). Scutellum quadrate with two groups of 4–5 setae on dorsal lateral aspects. Prespiracular setae on mesopleuron of 5 sharp setae and postspiracular setae of 22–26 stout, non-pigmented peg-like spiniforms ventrad and 8-10 slender, sharp, stout setae towards dorsal margin. Pteropleuron with 20–22 stout, sharp setae. Hypopleuron and sternopleuron without setae. Mesosternum and metasternum with short, stout, non-pigmented spiniform setae. Coxa 1 with 4–5 slen- der setae (spiniform setae absent). Trochanters 1 and 2 with spiniform setae; latter twice length of coxa 2. Setae on coxa 3 with 8–10 long slender setae on mesal surface and single long seta on lateral apex. Genital Aperture ( Figs. 5F–G ). Setae in R3–R5 long and slender, each on conical tubercle; R2 short, darkly pigmented, broad at base, sharp, and arising from lightly sclerotized plate; R1 of short fine setae subequal in length to that of R2. VSS of 3–4 long, slender setae; MSS with 2 slender setae; and DSS with 5 slender setae. Cercus 18µ in diameter, with 3 long setae, and several punctate alveoli.

Dimensions. Head and thorax: 1457µ (n = 2, range: 1451–1463µ); Labial theca, length: 560µ (n = 3, range: 538–573µ), width: 566µ (n = 3, range: 549–600µ); Genital aperture, diameter: 1195µ (n = 4, range: 771–1096µ), neosome length: 7800µ (n = 4, range: 7000–9300µ) ( Table 1).

Etymology. The species name A. longiascus is derived from the exceedingly long (Gr. lang) character of the sac-like (Gr. askos) neosome that is 2–4 times the length of the sac-like structure formed by the neosomatic growth of other species.

Remarks. The four specimens were obtained from a single specimen of H. armiger . The neosomes are exceedingly long ( Figs. 1B–C ) and reddish brown. Unfortunately, the site of attachment was not recorded. The genital apertures were not tilted away from the long axis of the vermiform neosomic abdomen. This might indicate that the specimens were located in the deeper tissues of the body of the animal, facilitating deeper encystment. The genital aperture of species occurring on the thin wing membranes, or along the wing phalanges tend to tilt away from the long axis to achieve a more perpendicular posture to the skin surface.

Figures

FIGURE 1. A–D. Whole neosomes (head and thorax contained within). A. Maabella stomalata, ex. R. amplexicaudatus, Philippines; note: “saddle” of thickened tissue; and enlargement to left of saddle indicating mature larva within. B–C. A. longiascus sp. nov., ex. H.?armiger, China (B = enlargement of genital aperture). D. A. phyllorhinae, ex. H. diadema, Malaysia. E. A. phyllorhinae, Hipposideros sp. near urogenital opening, West Papua (cyst = fibrous host cyst with neosome removed and ns = neosome). Scale = 1000µ.

FIGURE 4. A–C. Ascodipteron longiascus sp. nov., ex. H. armiger, China. A. Head and thorax, dorsal view (BM- 1034D, holotype). B. Labial theca, dorsal view (BM-1034B, paratype). C. Labial theca, ventral view (BM-1034A, paratype). Scale = 200µ.

FIGURE 5. A–G. Ascodipteron longiascus sp. nov.., ex. H. armiger, China. A. Thorax, lateral view (BM-1034B, paratype). B. Enlargement of mesopleuron and pteropleuron. C. Sternum, ventral overview (B-1034A, paratype). D. Enlargement of sternum. E. Lateral vertex and truncate dorsal margin of gena (BM-1034C, paratype). F. Genital aperture, (BM-1034D, holotype); note spiracles, G. Enlargement of proximal rows of setae; arrows note three types of setae. Scale A, C, & F = 200µ, B, D–E & G = 100µ.