Glabellula aggregata Evenhuis, 2013

Glabellula aggregata Evenhuis, 2013 View in CoL

Type material. Holotype ♂ SIZK DU-139 [ Rovno amber; examined]; Dubovka, Varash District .

Glabellula perkovskyi Evenhuis, 2013 , syn. nov. Holotype ♂ SIZK DU-140 a [ Rovno amber; examined]; Dubovka, Varash District .

Remarks. Amber inclusions of Mythicomyiidae are rather common in Dubovka and constitute 27% of all known dipterans from this locality ( Vlaskin & Perkovsky 2005; our data). The holotypes of both nominal species originated from a large piece of amber E-97 ( 9.7 g) with several syninclusions (SIZK DU-138: Mymaridae , Anaphes sp. ; SIZK DU-140: Rhagionidae , gen. sp.; SIZK DU-141: Aphelinidae , gen. sp.) as well as wood particles and numerous stellate hairs.

Evenhuis (2013: 375) indicated that the sample DU-140a (given as “DU-140”) with the holotype contains “another Glabellula specimen unfortunately cut sagittally when the piece was originally prepared and in too deteriorated condition to make a determination”. Still another Glabellula specimen is seen side by side with the cut one, and even a third strongly cut and undetermined specimen of Mythicomyiidae is present. In our re-examination of these pieces, we have counted a total of six better preserved specimens of Mythicomyiidae . The apical placement of the antennal style is well seen.

According to our observations, no stump vein emanates from crossvein bm-cu+dm-cu into cell bm+dm. Right wing of the holotype of Glabellula perkovskyi with very short, lightly coloured fold which is not perpendicular to the edge of cell bm-dm ( Evenhuis 2013: fig. 10) but runs subparallel to it. On the left wing, this fold is not touching the margin of cell bm-dm. These short folds are not visible on both wings of G. perkovskyi at the same time under any kind of lighting. These folds, unlike veins, are not visible from the wing underside. The right wing of the holotype of G. aggregata is visible in the inclusion only from the underside and only a small distal part of the left wing is visible, from underside as well. Only the left wing of one of the paratypes of G. aggregata is visible from above and in such a position that the discussed fold is barely discernible, as in the holotype of G. perkovskyi . Thus, the fold on the right wing of the holotype of G. perkovskyi is likely an artefact, and given that it was the reason to erect the second species from the same locality (both nominal species are described from the same piece of amber, but this was unknown to Evenhuis) a new synonymy is proposed: Glabellula aggregata Evenhuis, 2013 = Glabellula perkovskyi Evenhuis, 2013 , syn. nov. We have chosen to give G. aggregata precedence over G. perkovskyi because the terminalia of the holotype are better seen.