Mesoconius quadritheca, Marshall, 2019

Marshall, Stephen A., 2019, A revision of the genus Mesoconius Enderlein (Diptera, Micropezidae, Taeniapterinae), European Journal of Taxonomy 548, pp. 1-126 : 115-117

Mesoconius quadritheca sp. nov.

urn:lsid:zoobank.org:act:2494B1F0-9AFC-4177-901E-9A044662A2AB

Fig. 47

Etymology

The species name refers to the unusual complement of four spermathecae.

Material examined

Holotype

PERU • ♀; Cusco, Wayqecha Biological Station , 9 km NE of Challabamba; 13°10ʹ20ʺ S, 71°35ʹ00ʺ W; 2600–2700 m a.s.l.; 1–6 Dec. 2011; S.A. Marshall leg.; MUSM.

Paratype

PERU • 1 ♀; same collecting data as for holotype; MYCRO069-15 sequenced for CO1; DEBU .

Other material

PERU • 2 ♀♀; same collecting data as for holotype; in alcohol; DEBU .

Description (females only)

LENGTH. 17 mm.

COLOUR. Mostly black, fore tarsus white, except for ventral base of tarsomere 1, hind tarsus white basally and darkened distally, palpus yellowish apically. Mid and hind femora with a broad white band just beyond middle. Wing uniformly black. Abdominal pleuron dark.

HEAD. Epicephalon and paracephalon finely striate, shiny. Frontal vitta narrow and only slightly raised, anteriorly tapered to near anterior margin of frons, narrow and indistinct behind ocelli, where it expands to a microtrichose patch between very small postocellar bristles. Postocellar bristle small, inner vertical bristle minute and barely distinguishable from surrounding setulae. Fronto-orbital bristles absent.

THORAX. Scutum inconspicuously microtrichose, setulae inconspicuous, except for a densely setulose patch on each side of anterior margin. Cervical sclerite oblong, with a small, depressed anterior portion; posterior portion elevated, with a large, whitish oval patch(probably a dense field of sensillae).Prosternum microtrichose and conspicuously setulose. Postpronotal lobe almost bare, very sparsely microtrichose and very sparsely setulose, anterior surface vertical and shiny along dorsal margin, posterior surface almost vertical and microtrichose, except for ventral carina. Dorsocentral and scutellar bristles absent. Vertical row of katepisternal bristles black. Katatergite weakly swollen, without median process, evenly convex and microtrichose. All coxae with an anteroventral tuft of long black setae.

ABDOMEN. Abdominal segment 1 petiolate on basal half only, T2 short and expanded posteriorly. T3–5 narrow and depressed relative to T2 and T6. Pleuron greatly expanded on segments 3–5, micosetulose on dorsal third. Bursa with a small subquadrate body with a small and distal ventral receptacle, both spermathecal ducts arising separately from apex of bursa. Both ducts lead to paired spermathecae, with one duct and one pair of spermathecae slightly larger than the other. The smaller spermathecae are narrow and long, on short stems; the larger spermathecae are short, on longer convoluted stems.

Remarks

The equal length spermathecal ducts, four spermathecae, reduced head bristles, and relatively nonpetiolate abdominal base (only the basal part of segment one is narrowed) of this species are atypical for Mesoconius , as is the extended lower frons that covers part of the antennal socket. The general habitus, combined with a short oviscape, heavily pigmented wings and large size, are typical of the genus, but male specimens are needed to confirm this placement. Sequence data suggest that M. quadritheca sp. nov. belongs firmly in the genus, close to M. nigra sp. nov. ( Bolivia) and M. ruficrus sp. nov. ( Peru). Mesoconius quadritheca sp. nov. is similar to, and obviously closely related to, M. nigra sp. nov. from Bolivia. These species share the very unusual possession of four spermathecae, limited constriction at the abdominal base, narrowed T3–5, setose prosternum, and similar colour and general habitus, but M. nigra sp. nov. differs from M. quadritheca sp. nov. in having well-developed vertical and postocellar bristles (present but minute in M. quadritheca sp. nov.). Mesoconius ruficrus sp. nov. seems to be closely related, but has only three spermathecae.

Figures

Fig. 47. Mesoconius quadritheca sp. nov. A, D. Living ♀♀. B–C. Spermatheca and associated structures, dorsal and lateral views.