Ubristes rex, Reemer, 2017

Reemer, Menno, 2017, Ubristes rex sp. n., a new microdontine hoverfly from northern Brazil (Diptera: Syrphidae: Microdontinae), Zootaxa 4362 (2) : -

Ubristes rex sp. n.

Figs 1–8

Type specimen. HOLOTYPE. BRAZIL. Label 1: "BRASIL, Roraima, Serra / Pacaraima , BR-174 / 042704 N 610756W,"; label 2: " 800 m, 01–07.ix.1995 / J.A. Rafael, A.L. Henriques / & J. Vidal, Arm. Suspensa "; label 3: " INPA-DIP / 001537". Coll. INPA .

Description. FEMALE. Body size: 14.5 mm. Head. Figs 3–5. Face occupying 1/2 of head width in frontal view; yellow, with pair of oblique dark brown blotches ventrad of antennal fossa; golden yellow pilose, except for narrow bare mid line. Gena yellow with narrow dark brown from ventral eye margin to oral margin. Oral cavity with lateral margins produced well below ventral eye margin. Frons and vertex yellow, except for black mark directly around and anteriad of ocelli; black pilose, except frons laterally golden yellow pilose. Occiput yellow; black pilose dorsally, yellow pilose ventrally. Eye very sparsely and short pilose, with pili about as long as an ommatia diameter, appearing bare under low magnification. Antennal fossa about as wide as high. Antenna yellow; antennal ratio 7:1:12; basoflagellomere parallel-sided with narrowly rounded apex, with sensory pit located at 4/5 from base, within a groove that ranges from the base of the arista to close to the apex. Arista slender, about 2/3 of length of basoflagellomere. Thorax. Fig. 6. Postpronotum yellow; yellow pilose. Mesoscutum blackish brown except widely yellow along lateral margins and medially along posterior margin; yellow pilose on yellow parts and black pilose on blackish parts, except for a cross-shaped pattern of golden pile along median line and transverse suture. Postalar callus yellow; dark yellow pilose. Scutellum without calcars; yellow medially, dark brown laterally; yellow pilose on yellow part, black pilose on dark parts. Pleuron yellow, except anterior part of anepisternum with large black macula. Anterior and posterior part of anepisternum divided by a weak sulcus; anterior part yellow pilose, posterior part yellow pilose along posterior margin. Anepimeron yellow pilose on dorsal 1/3. Katatergum and anatergum long and short microtrichose, respectively. Katepisternum dorsally bare, ventrally yellow pilose. Katepimeron bare. Metasternum yellow pilose. Mediotergite largely dark brown except for anteromedian pale macula. Calypter yellow, halter yellow with brown knob. Wing. Hyaline, except brownish along anterior and median veins. Microtrichose, except bare on following parts: basal 1/4 of cell r1, basal 3/4 of cell br (but microtrichose along vena spuria), anterobasal 2/3 of cell bm, basal 1/10 of cell cup, and entirely bare on alula. Legs. Fig. 7. Entirely yellow and golden yellow pilose; pile on hind tibia and tarsus long, but not very dense. Coxae and trochanters yellow, except some vague dark maculae on hind coxa; golden yellow pilose. Abdomen. Figs 1, 8. Yellow, but tergites gradually turning darker (more brownish) towards apex of abdomen.

FIGURE 1–2. Ubristes rex sp. n. female (holotype). 1: habitus, dorsal. 2: habitus, lateral. Scale bars: 10 mm.

FIGURE 3–8. Ubristes rex sp. n. female (holotype). 3: head, frontal. 4: head, lateral. 5: head, dorsal. 6: thorax, dorsal. 7: hind leg. 8: abdomen, dorso-caudal. Scale bars: 1 mm.

Tergites 1 and 2 dark yellow pilose; tergite 3 dark yellow pilose with fascia of golden pile along posterior margin; tergites 4 and 5 dark yellow pilose on anterior half, black pilose on posterior half, with medially interrupted fascia of golden pile in between. Sternites yellow; long yellow pilose, sternite 1 with only two long thin setae.

Etymology. The specific epithet rex (‘king’, in Latin) was chosen to emphasize the large size of this species in comparison with the other known species of Ubristes .

Diagnosis. The only known specimen of Ubristes rex sp. n. is considerably larger than the other known Ubristes species: 14.5 mm instead of 8–11 mm. It differs from U. flavitibia by its yellowish colouration (blackish in U. flavitibia ). From U. ictericus Reemer, 2013a it differs by the entirely yellow pilose hind legs (partly black pilose in U. ictericus ) and the presence of golden pilose fasciae on tergites 3–5. From U. jaguarinus Reemer, 2013a it differs by the absence of dark brown maculae on the tergites. Furthermore, the face is produced more strongly ventrad in U. rex sp. n. than in the other three species.

Distribution. Only known from the state of Roraima in northern Brazil.