Dicerura furculata Mamaev, 1968

Jaschhof, Mathias & Spungis, Voldemars, 2018, Towards reliable identification of male Dicerura: descriptions of three new and seven poorly known species in the Palearctic region (Diptera: Cecidomyiidae, Porricondylinae), Zootaxa 4422 (1), pp. 85-103 : 95-96

Dicerura furculata Mamaev, 1968

= D. padi Mamaev, 1975 syn. nov.

Figs 19–21

Dicerura furculata is known from a very few specimens collected in Ukraine ( Mamaev 1968), Latvia ( Spungis

1987), and Finland ( Jaschhof et al. 2014). The only Finnish specimen, a male, is depicted here. Spungis (1987)

described the female of this species and referred to the larva as known but not yet described. Micrographs of the

holotype of D. furculata , which we compared here with the holotype specimen of D. padi , made clear that these

two species are identical, rendering D. padi a new junior synonym of D. furculata . Mamaev´s (1975) original

description of D. padi , based on specimens of both sexes from the Russian Far East, did not include illustrations

and is therefore of little help in the identification of this species.

Diagnosis. Dicerura furculata is in several respects an unusual, distinctive species. Most importantly, the apex

of the ejaculatory apodeme is bifurcate, as is typical of Dicerura , but the two tines of the fork are conjoined by an apparently solid, transparent membrane ( Fig. 21 , ↓1). Furthermore, the tegmen, which is elongate, subrectangular,

and membranous posteriorly, lacks any substructures ( Fig. 21 ). The gonostylus, whose outline resembles that in D.

barbata ( Fig. 10 ), is slightly bent, 2.5 times longer than broad, and provided with a long, slightly protruding lobe on the inside that bears dense, large microtrichia, a few fine setae but no bristles ( Fig. 20 , ↓2). Of the gonocoxites, the deeply U-shaped ventral emargination is both reinforced by sclerotization and darkly pigmented ( Fig. 19 , ↓3); the dorsoposterior portions appear bilobed due to the strongly projecting medial bridges ( Fig. 19 , ↓4); and the dorsal

apodemes are unusually short. The bilobed apex of the ninth tergite is provided with dense, thick microtrichia

( Spungis 1987: fig. 3.6).

Remarks. As noticed already by Mamaev (1968), D. furculata is unusual among Dicerura in having a short,

three-segmented palpus ( Spungis 1987: fig. 3.7). Empodia are vestigial and claws are provided with up to three

basal teeth. Mamaev´s (1975) statement that the palpus of D. padi would consist of only two segments is not

correct; we found three palpal segments in both the male and one of the females (the other remained unstudied) of

the original series. We observed some variation in the circumfila of male D. padi : in both the holotype and a

specimen from Latvia ( Spungis 1987) the extensions of a circumfilum merge posteriorly to form a loop, while in

the Finnish specimen studied here both extensions are usually free-ending and only exceptionally looped.

Material examined. Finland: male, Regio aboensis, Turku, Ruissalo, 20 June 2006, aspirator, M. Jaschhof (in

MZH). Holotype male of D. padi (specimen no. P-Di0142 in ZMUM), with the data as specified in the original

description ( Mamaev 1975).

Figures

FIGURES 19–21. Dicerura furculata, male, from Finland. 19: Genitalia, ventral. 20: Gonostylus, ventral. 21: Tegmen and ejaculatory apodeme, ventral. Scales 0.05 mm. Arrows refer to characters described in the diagnosis.

FIGURES 9–12. Dicerura barbata, male, from Sweden. 9: Ninth tergite, dorsal. 10: Gonostylus, ventral. 11: Genitalia, ventral. 12: Tegmen and ejaculatory apodeme, ventral. Scales 0.05 mm. Arrows refer to characters described in the diagnosis.