Dicranota ( Rhaphidolabis ) Osten Sacken, 1869

Dicranota ( Rhaphidolabis) Osten Sacken, 1869 View in CoL

Rhaphidolabis Osten Sacken, 1869: 284; Edwards 1938: 51, 61; Alexander 1950: 17; Ishida 1958: 40; Tjeder 1959: 5; Brindle 1963: 235: Mendl 1972: 150: Savchenko and Krivolutskaya 1976: 35; Savchenko 1983: 39; Savchenko 1986: 170; Savchenko 1989: 27.

Claduroides Brunetti, 1911: 284.

Type species.

Rhaphidolabis tenuipes Osten Sacken, 1869 (original designation) (Nearctic).

Redescription.

Small to medium-sized Dicranota crane flies with body length 4.3–9.0 mm and wing length 5.0– 9.5 mm. Colour varies from pale yellow to brownish yellow, to pale brown, dark brown, or dark grey.

Head. Antenna 13–17 - segmented, reaching to approx. or slightly beyond frontal margin of presutural scutum, if bent backwards. Length of apical antennomere varies depending on species, from shorter to nearly twice as long as preceding segment. Verticils usually short, from half the length to as long as the respective segment, longest reaching ≤ 1.5 × as long as respective segment.

Thorax. Longitudinal stripes of presutural scutum vary depending on species, some species with uniformly coloured scutum and any stripes lacking, some species with medial darkening, and other with three distinct longitudinal stripes. Wing could have small dark spots, surrounding cross-veins or vein branching points, but usually without any darker areas besides stigma, stigma is often missing too. Venation: Rs usually short, sometimes longer; cell r 3 with short stem, or stem is missing, radial sector branches into R 2 + 3 + 4 and R 5, or R 4 in direct alignment with Rs; discal cell open due to atrophy of m-m; cell m 1 always present. Due to individual variation in wing venation, most species cannot be reliably identified just based on wing characters. Wing squama often with few setae.

Abdomen. Posterior margin of epandrium species specific, often with medial and lateral lobes, sometimes concave at middle. Gonocoxite varies depending on species, sometimes simple, often with subapical dorsal lobe covered with small spines, interbase long, sometimes complicated. Two, sometimes one pair of gonostyli, outer gonostylus fleshy, covered with abundant small black spines, inner gonostylus usually paler, elongate, bearing just few small pale spines. If gonostylus single, then it has complicated structure, usually bearing outer and inner lobes. Aedeagus simple, paramere elongate, usually curved at apex. Ovipositor with long cercus and hypogynial valve. Two or three spermathecae.

The subgenus Dicranota ( Rhaphidolabis) includes 112 species ( Oosterbroek 2025) (two species are added in this publication). It is most diverse in the Oriental region, 45 species, then Eastern Palaearctic, 37 species (with one species also occurring in the Western Palaearctic, three species shared with Oriental fauna), Nearctic, 31 species. Two species are recorded from Neotropics.