Bradysia bigeminata Heller & Hippa & Vilkamaa 2015, sp. nov.

Bradysia bigeminata sp. nov.

urn:lsid:zoobank.org:act: 2B3EB8AC-0D40-48B8-8453-AC9CA78B6316

Fig. 2 A–B

Diagnosis

Small-sized Bradysia. Dark brown. Maxillary palpus with 2 segments. Wing length 1.5 mm, anal lobe strong. Gonostylus narrow, without apical tooth, with 4 subequal megasetae.

Etymology

The name is derived from the Latin words bis - (two) and geminus (twin), referring to the two pairs of gonostylar megasetae of the species.

Material examined

Holotype

FINLAND: ♂, Ostrobothnia borealis, Pudasjärvi, Murto-oja (Grid 7267183:3525642), near a brook, Malaise trap, 1 May–3 Jul. 2006, J. Ilmonen & J. Salmela, MZH.

Paratypes

FINLAND: Karelia borealis, Kuhmo, Elimyssalo, bred from Fomitopsis rosea collected 23– 28 May 1998, A. Komonen, 1 ♂, MZH.

CANADA, Ontario, Sudbury Co., Chapleau, Nimitz Forest, from wind thrown Pinus banksiana trees, photoeclector, 10– 24 Jul. 2012, R. Deady & T. Work, 14 ♂♂, 1 [no. 8622] in PKHH, 3 [ZMFK- TIS-2527999, ZMFK-TIS-2527999, ZMFK-TIS-2528275] in ZMFK, 1 in MZH, 9 in PRDM; same data but 16– 29 May 2012, 4 ♂♂, PRDM, 1 ♂, MZH; same data but 28 May–12 Jun. 2012, 2 ♂♂, PRDM, 1 ♂, MZH; same data but 25 Apr.–11 Jul. 2012, 2 ♂♂, PRDM; same data but 23 Jul.–8 Aug. 2012, 5 ♂♂, PRDM; same data but 7–20 Aug. 2012, 1 ♂, PRDM; Ontario, Sudbury Co., Chapleau, Superior Forest, mature (99 years old) stand composed of 90% Pinus banksiana and 10% P. mariana with an understory shrub layer of Vaccinium, very wet with considerable bryophyte coverage, pine log, photoeclector, 21 Jul.–6 Aug. 2013, R. Deady & T. Work, 18 ♂♂, PRDM; same data but 5–19 Aug. 2013, 15 ♂♂, PRDM; same data but 7–22 Jul. 2013, 2 ♂♂, PRDM, 1 ♂, MZH.

Description (male)

HEAD. Dark brown, antennal flagellomeres unicolorous brown; maxillary palpus very pale brown. Eye bridge 2–3 facets wide. Face with 23 scattered longer and shorter setae. Clypeus with 1 seta. Maxillary palpus with 2 segments; segment 1 longer than segment 2, segment 1 with 1 seta, with dorsal patch of sensilla; surface of antennal flagellomeres smooth, body of flagellomere 4 2.65× as long as wide, neck shorter than broad, longest setae longer than width of flagellomere.

THORAX. Dark brown, setae pale. Anterior pronotum with 3 setae. Episternum 1 with 7 setae. Scutum with long dorsocentrals, with some longer and shorter laterals, scutellum with 4 longer and some short setae.

WING. Hyalinous. Length 1.5 mm. Width/length 0.50. Anal lobe strong. Veins distinct. R1/R 0.55. c/ w 0.65. r-m and bM subequal in length, both non-setose.

LEGS. Yellow. Coxal setae pale. Front tibial organ with pale vestiture forming a short row. Front tibial spur as long as tibial width. Tibial spurs of middle and hind tibia subequal. Tarsal setosity normal. Claws without teeth.

ABDOMEN. Brown, setae pale.

HYPOPYGIUM (Fig. 2 A–B). Brown, concolorous with abdomen.

GONOCOXA. Basally broad, longer than gonostylus, mesial margin with sparse setosity.

GONOSTYLUS. Narrow, rather evenly broad and straight, tumid, with mesial side impressed at apical half; with dense apical setosity, without apical tooth, with two pairs of sharp subapical megasetae. Tegmen truncate, with straight lateral sides, laterally and apically sclerotized, with small area of solitary aedeagal teeth. Aedeagal apodeme rather long.

Remarks

Bradysia bigeminata sp. nov. is here formally assigned to the genus Bradysia because of the presence of a comb-like row of elements in its tibial organ and because of its subequal middle and hind tibial spurs, but it cannot be placed in one of the currently defined species groups. In the structure of its gonostylus it also resembles the species of the Corynoptera vagula group (see Vilkamaa & Hippa 2006). By its elongated gonostylus with four apical megasetae, and by its short front tibial comb placed in a non-setose area at the apical part of the tibia, Bradysia bigeminata sp. nov. resembles Scatopsciara (Xenopygina) vinea Rudzinski & Baumann, 2013, but differs in having a simpler tegmen and a different placement of the gonostylar megasetae. In a molecular phylogenetic analysis, the Corynoptera vagula group of species appeared close to species of Scatopsciara Edwards (Shin et al. 2013). In this analysis, no species of Scatopsciara (Xenopygina) Frey, 1942 was included. It is obvious that a more inclusive analysis is needed to clarify the relationships of B. bigeminata sp. nov., the Corynoptera vagula group and the species currently placed in Scatopsciara (Xenopygina).

Ecology and distribution

Bradysia bigeminata sp. nov. was found to be very numerous in deadwood sampled in Canada. This may suggest deadwood to be the natural habitat of the species. The COI sequence of the collected specimens was allocated to the BIN ACA4746 on BOLD (www.boldsystems.org), and, interestingly, the results showed that the species is widely distributed in Eastern Canada.