Downeshelea lanei Felippe-Bauer & Borkent, n. sp.

Downeshelea lanei Felippe-Bauer & Borkent, n. sp.

Figs. 1–14

Monohelea cebacoi: Lane and Wirth 1964: 218 (in part; male, Brazilian specimens).

Diagnosis. Only species of Downeshelea with dark spots on the apical portion of r3 and m1 (Figs. 1, 2), dark areas on the subapical portion of the fore- and midfemora (Fig. 7) and the mid portion of each paramere straight and the distal portion sharply directed medially (Fig. 14).

Female. Head. Brown. Eyes (Fig. 4) bare, narrowly contiguous. Antenna (Fig. 3) brown except on basal portion of flagellomeres; flagellomeres cylindrical, elongate; antennal ratio 0.97–1.15 (1.06; n=3); palpus (Fig. 5) uniformly brown, longer than proboscis; segment 3 cylindrical, proximal 2/3 slightly swollen, with moderately broad, deep sensory pit at midlength; palpal ratio 2.5–2.7 (2.6; n=3). Mandible with 10–12 teeth.

Thorax. Brown, without definite pattern in slide mounted specimens. Wing (Fig. 1) hyaline, with dark thick setae on costa, scarce apical microtrichia; two conspicuous black spots, one located on r-m extending posteriorly to medial fork and M2, the other in r3, extending posteriorly from end of 2nd radial cell to M1; four conspicuous grayish spots: 1st in apical portion of r3, 2nd near apex of M1 extending to wing margin in m1, 3rd sigmoid shaped near apex of M2 extending to wing margin in m2, 4th with markings on fork of CuA1 and CuA2 extending on these veins, extending into cua1 and anal cell; 2nd radial cell nearly twice as long as 1st; wing length 1.35–1.54 (1.43; n=3) mm; breadth 0.54–0.65 (0.59; n=3) mm; costal ratio 0.79–0.82 (0.80, n=3). Halter stem pale, knob brown. Legs with femora, tibiae (Fig. 7) yellowish brown, fore- and midfemur slightly darker on subapical portions, hind femur darker on subapical third, hind tibia darker on proximal half and apical portion; femorotibial joint areas yellowish; fore- and hind tibiae with apical spur, longer on foreleg; hind tibial comb with 6–7 large setae; lengths of trochanters, femora, tibiae of fore-, mid-, hind legs: 135-595-568, 108-730-676, 135-838-757 Μm (n=3). Tarsi (Fig. 8) pale, pilose; palisade setae in single row on hind tarsomere 1; fore-, hind tarsomere 1 with one basal, one apical spine; mid tarsomere 1 with 2 basal, 2 apical, 1–3 other ventral spines; apical spines of tarsomeres 2–4 of fore-, mid-, hind legs: 2-2-2, 2-2-2, 1-1-2, basal spines absent; fore-, mid-, hind tarsal ratios: 2.3, 2.5, 2.5 (n=3); claws of fore-, midlegs paired, equal, about 0.7 length of their respective tarsomeres 5; hind leg with single claw, about 1.1 x as long as tarsomere 5.

Abdomen. Brown. Two slightly unequal subspherical spermathecae (Fig. 6), measuring 64 by 58 Μm and 50 by 48 Μm; small rudimentary 3rd present, 10 Μm long.

Male. Similar to female with the usual sexual differences; antenna (Fig. 9) with pedicel and flagellomeres 11– 13 brown; 2–9 somewhat barrel-shaped, 10 about 3x longer than wide, 11–13 elongate; antennal ratio 0.92 (n=2); palpus as in Fig. 10, palpal ratio 2.8. Legs with femora, tibiae as in Fig. 12. Tarsi (Fig. 11) pale, pilose; fore-, hind tarsomere 1 each with one basal and one apical spine; midleg tarsomere 1 with 2 basal, 2 apical, 1–5 other ventral spines; apical spines of tarsomeres 2–4 of fore-, mid-, hind legs: 2-2-2, 2-2-2, 1-1-1, basal spines absent; fore-, mid-, hind tarsal ratios: 2.2, 2.5, 2.4. Wing (Fig. 2) hyaline, pattern of dark spots as in female, narrower than female; wing length 1.32–1.35 (1.33, n=2) mm; breadth 0.43 (n=2) mm; costal ratio 0.70–0.75 (0.73, n=2). Terminalia (Fig. 13): tergite 9 missing in holotype specimen, damaged in paratype specimen; sternite 9 spiculate, basal portion not visible, posterior margin with large, long, greatly convex median extension bearing two long setae. Gonocoxite elongate, straight, twice as long as basal width; gonostylus nearly straight, 0.63 length of gonocoxite, proximal ½ moderately pilose. Parameres (Fig. 14) 1.4x longer than aedeagus, broadly fused basally; stem thickened on proximal portion, mid portion nearly straight, slender, distal portion a long, hyaline, very slender, straight, medially directed process. Aedeagus (Fig. 13) nearly subtriangular, uniformly sclerotized, basal arch extending 0.45 of total length, distal portion with moderately deep mesal excavation and two slender, pointed, serrate processes.

Distribution and bionomics. Downeshelea lanei is known only from the northern Brazilian states of Amazonas and Pará. Some specimens were collected by Thomas H.G. Aitken in Floresta da Á rea de Pesquisas Ecológicas do Guamá (APEG Forest), with a light trap at ground level in a typical freshwater ecosystem.

Types. Holotype 3 adult, in drop of Canada Balsam on five celluloid strips on pin, labeled " Holotype Downeshelea lanei ", " Monohelea cebacoi, paratype, John Lane det.1961, drawn, Brazil, Pará, Cachimbo, I. 1956, S.J. Oliveira col. #14,943" (FSPC). Allotype female, labeled "Allotype Downeshelea lanei ", " Downeshelea cebacoi, Brazil, Amazon River, Floresta, Prainha, 16.IX.1969, HA Wright col., light trap", #458 (CCER). Paratypes, 1 male, 2 females, as follows: 1 male, BRAZIL, Pará, Belém, Floresta da Á rea de Pesquisas Ecológicas do Guamá (APEG Forest), IV.1970, THG Aitken col., light trap., #459 (CCER); 1 female, same data, except VII.1970, sticky trap, #460 (CCER); 1 female, same data, except II.1970, "terra firme" (CNCI).

Etymology. This species is named in honor of Dr. John Lane in recognition of his important contributions to the study of Brazilian Ceratopogonidae and other nematocerous Diptera.

Taxonomic discussion. Downeshelea lanei most closely resembles D. cebacoi especially in its similar wing pattern. It can be distinguished from that species by the darker areas on the subapical portions of the fore- and midfemora (fore-, midfemora entirely yellowish brown in D. cebacoi) and the parameres with the mid portion of each stem nearly straight and the very slender distal portion medially directed (Fig. 14) (stem sinuous and distal portion a posteriorly directed process in D. cebacoi (Fig. 23)).

A key to the Neotropical species of Downeshelea was provided by Lane and Wirth (1964), as members of Monohelea Kieffer. Males of Downeshelea lanei key out to couplet 7 in that key and can be distinguished from D. cebacoi by the shape of their parameres which have a straight stem and a medially directed distal portion.