Megagrapha starki Bartak & Grootaert, 2021

Kanavalova, Liliana, Grootaert, Patrick, Kubik, Stepan & Bartak, Miroslav, 2021, Four new West Palaearctic species and new distributional records of Hybotidae (Diptera), ZooKeys 1019, pp. 141-162 : 141

Megagrapha starki Bartak & Grootaert sp. nov. Figs 3 , 4 , 5 , 6

Type material.

Holotype ♂, Slovakia: Muráňska planina NPR, Šarkanica, 540 m, MT, 48°42'46"N, 19°59'52"E, M. Tkoč, 26.iv.-15.vi.2017 (CULSP). Paratypes: Slovakia, 1♂, Muráňska planina NP, 580 m, MT, 48°42'46"N, 19°59'56"E, J. Roháček, 14.vi.-11.vii.2017 (dissect., RBINS); Poland: 1♂, Bialowieza, 'Bialowieza Forest’, Promotion Area, ‘Lesna’ Reserve, 15 km SE of core zone of NP, 160 m a.s.l., 120 year old Carpinus betulus fogged with pyrethrum, 52°37'41"N, 23°46'12"E, A. Floren, 28.vi. 2001 (CAStH); Russia: 1♂, SW Moscow, Moskovskiy, forest edge, YPT traps, 55°35'16"N, 37°19'58"E, K. Tomkovich, 1-4.viii.2014 (ZMMU).

Diagnosis.

A species of Megagrapha Melander with patterned wings and modified male fore and mid basitarsi, very similar to Nearctic M. exquisita (Malloch, 1923). However, the newly described species differs in the colour of the mesoscutum (Fig. 3 ), the dark pattern on the wing (Fig. 5 ), the shape of the postpedicel (Fig. 4 ) and the male terminalia (Fig. 6 ).

Etymology.

The species epithet, Megagrapha starki , is a Latin genitive patronym given in honour of German dipterist Andreas Stark (Halle (Saale)), who first recognised this species as new, acknowledging his contribution to the knowledge of world Empidoidea .

Description.

Male head black, rounded in anterior view and ovoid in lateral view. Large eyes with dense and relatively long ommatrichia, all facets subequal in size. Frons very narrow (linear, narrower in lower part than diameter of one ommatidium, widening towards ocellar triangle). Slightly prominent ocellar triangle and adjacent parts of frons and vertex sublustrous, with 2 pairs of short, subequally long and pale ocellars (about 0.10 mm long), with several similar setae posteriorly. Occiput microtrichose (subshiny), with dense yellowish-brown to black setae on dorsal third similar in length to ocellars, ventrally with fewer short, pale setae, posteriorly with several black setae. Face very narrow dorsally and widening ventrally, microtrichose, without setae, gena indistinct. Palpus brown, relatively large (0.22 mm long) and ovoid, slightly narrowing towards tip, covered with relatively long black setae. Labrum yellow, only slightly longer than palpus, labellum narrow with several setae. Antenna yellow (Fig. 4 ). Scape without setae, 0.08 mm long, pedicel (0.05 mm long) with circlet of short black setae, postpedicel (0.24 mm long) elongated, with rather long narrow apical half. Stylus (0.15 mm long) with several slightly elongated darkened setulae (especially in apical part). Thorax yellow with brown pattern in form of 2 longitudinal stripes on mesoscutum spreading from black antepronotum posteriorly, bent near scutellum towards postalar calli and connected with a broad stripe medially in front of scutellum (dark pattern in dorsal view roughly U-shaped). Postpronotum and adjacent parts of mesoscutum, including notopleuron, brown, slightly brownish parts occur below wing base including mediotergite. Scutellum black and microtrichose except basolateral corners. Mesoscutum mostly lustrous, pleura shiny except dorsoposterior part of anepisternum. Both anterior and posterior spiracles deep black. Chaetotaxy: antepronotum with 4-5 pale setulae on each side, 3 notopleurals, 1 short postalar, 3 pairs of pale scutellars. Mesoscutum densely covered with black setulae anteriorly (also on postpronotum and adjacent areas) and white setulae posteriorly, setae longer in presutural area with 1 not very prominent prescutellar pair. Pleura with several black setae dorsally on anepisternum. Legs including coxae very pale (almost whitish-) yellow, rather densely covered with short, whitish setulae, some longer setae only preapically on ventral side of all femora. Basitarsus of fore leg with narrow ventral process and basitarsus of mid leg narrowed basally and widened apically, with short ventral apical projection. Second mid tarsomere with dense setulae ventrally. Wing (Fig. 5 ) with distinct dark pattern, covered on both sides with relatively long microtrichia. Basal costal seta only slightly differentiated. Sc incomplete, closely approximated to R1 and vanishing at about middle. Costa ends at tip of M1 vein. Halter yellow, calypter black with yellow margin and long black fringes. Abdomen subshiny, with brown (and brown setose) tergites and yellow (pale setose) sternites, lateromarginal setae on tergites as long as or longer than segments. Terminalia as in Fig. 6A-D . Cerci narrow, equally long, shorter than right epandrial lamella. Left surstylus composed of lower lobe (ll) and digitiform upper lobe (ul), bearing setae longer than lobe. Length: body 2.4 mm, wing 2.6 mm.

Female. Unknown. However, all allied species are sexually dimorphic with dark-coloured females.

Remarks.

Stark (2008) already recognized the species as new and announced a separate paper on Megagrapha : "Stark A (2009), in press. Description of two species of the genus Megagrapha Melander ( Diptera , Empidoidea , Hybotidae , Drapetini ) from the canopy of trees in European primeval forests. Studia dipterologica 16(2)". However, this paper was never published. Andreas Stark kindly sent us illustrations and locality data and his male was included in the type series.

The new species described above is very similar to the Nearctic M. exquisita as redescribed by Chillcott and Teskey (1983) and by Chillcott (1958 - male as M. pubescens (Loew, 1862)) in the patterned wings and modified basitarsi of the fore and mid legs. However, both species strikingly differ in the colour of the mesoscutum (reddish yellow in M. exquisita - ME, with brown stripes in M. starki - MS), in the dark pattern on the wing (dark around crossveins of basal cells in ME, light in MS), in the shape of the postpedicel (pear-shaped in ME, with long narrow apical half in MS; Fig. 4 ) and in the male terminalia (left surstylus longer and more slender in ME than in MS, with bent tip, and apical bristles on upper lobe of digitiform left surstylus shorter than lobe in ME but longer in MS; Fig. 6 ). Megagrapha europaea Papp & Földvári, 2001, the only other known European representative of the genus, has clear wings in the male and mesoscutum yellow without dark stripes. For further differences, see comments under M. europaea .

Distribution.

Slovakia, Poland, European Russia.

Figures

Figure 3. Megagrapha starki sp. nov. Male habitus, paratype.

Figure 4. Megagrapha starki sp. nov., male antenna, paratype.

Figure 5. Megagrapha starki sp. nov., male wing, paratype.

Figure 6. Megagrapha starki sp. nov., male terminalia A right epandrial lamella B epandrium with cerci, dorsal C left epandrial lamella D detail of phallus. Abbr. hyp: hypandrium; lc: left cercus; lel: left epandrial lamella; ll: lower lobe of left surstylus; ul: upper lobe of left surstylus; rel: right epandrial lamella. Scale bar: 0.1 mm.