Asindulum coxale Loew, 1870: 132

Fitzgerald, Scott J., 2023, The Nearctic species of Asindulum Latreille and Macrorrhyncha Winnertz (Diptera: Keroplatidae), Zootaxa 5351 (1), pp. 72-106 : 74-78

Asindulum coxale Loew, 1870: 132 .

Figs. 1–2 , 5–15 , 85

Type. Holotype female ( MCZC), not physically examined, but photos of the holotype studied ( Fig. 6 ): CANADA: QUEBEC: “Hudsons-Bay Territory; Kennicott.”

Material examined. CANADA: MANITOBA: 5 mi. SW. Shilo , 2.VIII.1958, J.G. Chillocott, Tamarack, 1f ( CNCI) ; ONTARIO: Ottawa, 22.VII.1954, W.R.M. Mason, 1f ( CNCI) ; Maynooth, 5.IX.1953, swept from beaver meadow, J.F. McAlpine, 1m ( CNCI) ; Copetown, resort, 12 July [no year], J.R. Vockeroth, 10m 3f, ( SFC) ; QUEBEC: Laniel, 20.VIII.1939, J.L. Hitchon, Exp. No. 12128-5, 1f ( CNCI) ; Masham Twp. , Gatineau Co., 21.VII.1974, D.M. Wood, 1f ( CNCI) ; USA: NEW HAMPSHIRE: Straf Co., 1 mi. NE Durham , VII.9 –14.1983, A. T . Eaton, Malaise trap, 1f ( DENH) .

Redescription. Male ( Fig. 5 ). Body length ca. 5.0–7.0 mm (n = 2). Mouthparts as Figs. 1–2 ; long, reaching well beyond apex of fore coxa. Thorax cream-colored with three dark brown to black stripes on mesonotum (lateral stripes truncated anteriorly) that are sometimes entirely fused into a dark central area and sometimes mesonotum entirely dark brown (without narrow pale margins). Thoracic pleura brown. Anterior spiracle without posterior setae. Legs cream to pale yellowish in color, appearing darker distally due to more densely placed trichia. Hind tibial trichia irregularly arranged. Wing ca. 4.0–5.0 mm (mean = 4.8 mm, n = 11), often slightly brown fumose distally. CuP reaching wing margin. Abdomen dark brown, sometimes with bright cream to orangish areas on anterolateral corners of tergites 7 and 8. Male terminalia as Figs. 7–12 . Male tergite 9 with posterolateral corners each produced into an elongate, narrow, setose, apically rounded lobe, and posterosubmedially (on each side of broad u-shaped posteromedian emargination) with a pair of laterally compressed digitate, ventrolaterally-curved, bare lobes. Ventrally, gonocoxites medially divided, resulting in a pair of somewhat triangular sclerites which are posteriorly rounded. In lateral view, lateral gonocoxite broadly rounded apically and lacking dorsal process dorsomedially. Gonostylus small, talon-like, apically-hooked and acute, with some strong subapical setae. Sperm pump (possibly fused with parameres) complex, large and anteriorly elongated, with apodemes reaching into abdominal segment 6; notable are two pairs of very long, more laterally-positioned apodemes (one pair more ventral, one pair more dorsal) and an ejaculatory apodeme which is very strongly laterally compressed. The posterior apex of the sperm pump is bulbous with a pair of ventral lobes.

Female. As male except as follows: Body length ca. 5.0–6.0 mm (n = 2). Wing 4.5–6.0 mm (mean = 4.9, n = 7). Abdomen usually dark brown, sometimes with posterior segments with bright cream to orangish tinge or sometimes lighter over most of abdomen with palest areas more concentrated to anterior edge or anterolateral corners of tergites. Abdomen broader than male and often slightly expanded (expanding to segments 4–5 and then tapering again) and flattened posteriorly. Segments beyond tergite 7 telescoped internally. Female terminalia as Figs. 13–15 . Cerci fleshy, setose, oval, pad-like. Sternite 10 broadly rounded posteriorly.

Diagnosis. Both sexes with mouthparts extending well beyond apex of fore coxa and coxae cream to pale yellowish in color. Male tergite 9 with both posterolateral and submedian lobes.

Comments. This species was treated in the genus Macrorrhyncha by Evenhuis (2006). However, the female holotype has CuP reaching the wing margin. This condition is diagnostic for Asindulum ( Fig. 6 ) so it is reinstated in this genus. Some specimens similar in general habitus to A. coxale (and labelled as “ Macrorrhyncha coxale ” in CNCI) have CuP not reaching the wing margin and anterior spiracle with posterior setae; these specimens belong to the genus Macrorrhyncha and have been described below as M. borealis n. sp. (see also Comments under M. borealis ).

A. coxale is very similar to the Palearctic A. nigrum and the two are undoubtedly sister-taxa based on two synapomorphies: 1) mouthparts distinctly longer than coxa 1, and 2) posterior margin of tergite 9 with submedian lobes. A. nigrum can be differentiated by the black coxae, the submedian lobe of tergite 9 of male more spatulate apically, and the gonostylus shorter with a more pronounced basal swelling.

Distribution ( Fig. 85 ). Northeastern Nearctic . Specimens were examined from Canada (Manitoba, Ontario, Quebec) and USA (New Hampshire). Additionally, Evenhuis (2006) records this species from Maine, USA. While the Maine record is conceivable given the other distribution records, considering the confusion over the identity of this species, the Maine record requires confirmation.

Biology. Unknown, though one specimen was “swept from beaver meadow” which suggests wet, grassy habitats similar to that described for A. nigrum in Europe ( Chandler 1991, Falk & Chandler 2005).

Figures

FIGURE 5. Asindulum coxale, male habitus. Scale = ca. 1.0 mm.

FIGURE 6. Holotype female of Asindulum coxale and labels. Clockwise spiral from top: Wing, scale bar = 1.0 mm. Head (anterior), scale bar = 1.0 mm. Habitus (anteroventral), scale bar = 2.0 mm. Habitus (posterodorsal), scale bar = 2.0 mm. Habitus (lateral), scale bar = 2.0 mm. Type labels. Photos by Charles Whittemore Farnum, credited to, and used with permission by, Museum of Comparative Zoology, Harvard University. Abbreviations: cx1, coxa 1; lbl, labellum.

FIGURES 7–10. Asindulum coxale, male terminalia. 7. Dorsal. 8. Ventral. 9. Lateral. 10. Gonostylus, posterolateral (not to scale). Scale bar = ca. 0.5 mm. Abbreviations: ce, cercus; gc, gonocoxite; gs, gonostylus; llgc, lateral lobe of gonocoxite; llt9, lateral lobe of tergite 9; smlt9, submedian lobe of t9; t9, tergite 9.

FIGURES 11–12. Asindulum coxale, male terminalia including sperm pump. 11. Ventral. 12. Lateral. Scale = ca. 0.5 mm. Abbreviations: da, dorsal apodeme; ea, ejaculatory apodeme; gc, gonocoxite; t9, tergite 9 (t9 damaged in this specimen); va, ventral apodeme.

FIGURES 13–15. Asindulum coxale, female terminalia.13. Ventral. 14. Dorsal. 15. Lateral. Scale = ca. 0.25 mm.Abbreviations: ce, cercus; s7, sternite 7; s8, sternite 8; s10, sternite 10; t7, tergite 7.

FIGURE 85. Distribution map for Asindulum coxale, Asindulum flavidum n. sp., and Asindulum mexicanum n. sp..

FIGURES 1–4. Asindulum heads, males. 1. A. coxale, anterior. 2. A. coxale, lateral. 3. A. montanum, anterior. 4. A. montanum, lateral. Scale bars = ca. 0.5 mm. Abbreviations: asp, anterior spiracle; clyp, clypeus; cx1, coxa 1; hyphar, hypopharynx; lab, labium, lbl, labellum; lbr, labrum; mx, maxilla; plp, palpus.