Dasyomma chrysopilum, Woodley, Norman E., 2007

Woodley, Norman E., 2007, Notes on South American Dasyomma, with the description of a remarkable new species from Chile (Diptera: Athericidae), Zootaxa 1443, pp. 29-35 : 33-34

Dasyomma chrysopilum sp. nov.

( Figs. 5–8 )

Diagnosis. Dasyomma chrysopilum sp. nov. can be immediately separated from all other known species of the genus by having dense, semi-appressed golden pilosity on the abdominal tergites ( Figs. 5–8 ), clearly an autapomorphic character state. It fits in the subgenus Dasyomma as recognized by Malloch, as it has fine black setae along vein CuA where it forms the posterior border of cell bm. In Malloch’s (1932) key, D. chrysopilum sp. nov. keys to couplet 2 but then does not fit either half of that couplet because of the abdominal coloration that is black but not at all glossy. In Coscarón & Coscarón’s (1995) key, the female of D. chrysopilum sp. nov. keys to D. fulvum (Philippi) , but the male does not key beyond couplet 6 because the body color does not fit either part of the couplet.

Description. Male. General body coloration grayish black, with gray tomentum of varying density present over most of the integument giving an overall grayish appearance with conspicuous pale golden pilosity ( Figs. 5–6 ).

Head and appendages black except for first antennal flagellomere which is bright orangish yellow but usually black on basal one-third. Eyes holoptic with brownish pilosity that is about the length of scape + pedicel. Frons, face, and parafacials densely tomentose but without pilosity; frons depressed medially, the depression extending between antennae. Ocellar tubercle with dark hairs, gena and occiput with pale golden hairs, the latter with a few dark hairs intermixed. Antennal scape and pedicel as well as palp with mostly erect black pilosity, the latter with a few paler hairs sometimes present basally. Basal part of antennal flagellum subequal in size to pedicel.

Thorax with fine, more or less uniform pale gray tomentum not completely obscuring surface. Scutum and scutellum with uniform long, erect, pale golden pilosity, scutum with posterior two-thirds or more also with dense, appressed golden pilosity. Erect, golden pilosity present on propleuron, most of anepisternum, upper part of katepisternum, anterior half of anepimeron and most of laterotergite. Wing hyaline, veins pale yellow, cell r1 beyond proximal fork in vein R (pterostigma of Coscarón & Coscarón (1995)) and anterior part of cell br yellowish. Tegula black. Veins R1, base of R4+5 to just beyond crossvein r-m, and CuA nearly to apex of cell bm with fine black setulae. Halter completely pale yellow with only basal region vaguely darker. Legs grayish black, tarsomere 1 and basal part of 2 on midleg, and tarsomeres 1–3 of hind leg, dark yellowish. Anterior face of coxae and femora, especially posteriorly, with fine, erect golden pilosity. Tibiae and tarsi with short black vestiture, but sparse, longer, slightly curled hairs present on ventral surface of front tarsus.

Abdomen completely gray tomentose, tergites 1–6 with long, dense, mostly appressed golden pilosity, more erect laterally, sternites with uniform erect pilosity that is mostly shorter and sparser. Terminalia concolorous with anterior part of abdomen with golden pilosity that has some darker hairs intermixed, circus slightly more yellowish.

Length 5.0 – 6.5 mm.

Female. Figs. 7–8 . Differs from male as follows: Head completely yellow except for ocellar triangle, antennal style, extreme tip of palp, and proboscis which are black; antennal scape and pedicel with slight dark infuscation. Eyes dichoptic, frons 0.38 of head width. Eye pilosity shorter, about as long as pedicel. Frons convex, moderately shiny except for narrow lateral margins that are whitish tomentose, with a small patch of black hairs on each side just above antennal bases. Face with wider tomentose margins, medially slightly shiny, with a few dark and pale hairs medially. Palpi with pale golden pilosity but with a few dark hairs at extreme apex.

Thorax orangish yellow (darker than head), with proepisternum, proepimeron, lower two-thirds of katepisternum and meron, two small spots on anepimeron, metanepisternum and metakatepisternum grayish black. Tegula with posterior half yellow.

Abdomen essentially as in male, but cercus dark yellow.

Length 5.7 mm.

Specimens examined. Holotype ♂, CHILE: Malleco Province, Cordillera de las Raices, 40 km E of Curacautin, 1650 meters, 7–8 February 1979, D. & M. Davis & B. Akerbergs (USNM). Paratypes: 1♂, 1Ψ, same data as holotype (USNM). 1♂, CHILE: Ñuble Province, 6 km E of Cueva de los Pincheira, approximately 1250 meters, 24–25 January 1999, P. & M. Hibbs, Malaise trap (USNM).

Etymology. The species epithet refers to the very distinctive golden pilosity present on the abdomen of both sexes.

Remarks. The golden pilosity present on this species is unique among Dasyomma , and gives the species a very distinctive appearance. I have not examined the male genitalia of this species, as this has not been done for most of the described species, but is advisable when the genus is revised in the future.

Figures

FIGURES 5 – 8. Dasyomma chrysopilum, sp. nov. 5, male holotype, dorsal view. 6, male holotype, lateral view. 7, female paratype, dorsal view. 8, female paratype, semilateral view.