Burmasphex sulcatus, Melo & Rosa, 2018

† Burmasphex sulcatus sp. nov.

urn:lsid:zoobank.org:act:F66B68B3-B80E-4AB3-9806-D234E5F2EFEC

( Figs. 1–6 View Figs )

Diagnosis and remarks. This species differs from † Burmasphex pilosus sp. nov. by its smaller body size, shorter and less conspicuous pilosity, especially in the first two terga, the proportions of the basal flagellomeres, the distance between posterior ocelli shorter than the ocello-orbital distance, the position of 1m-cu in the forewing (touching M + Rs basal to their bifurcation), the interrupted transverse carina of the propodeum, and a marked constriction at the base of the 3rd tergum.

Description. Holotype male. Measurements (in mm). Approximate body length, 3.8; maximum head width, 1.1; forewing length, 2.6; maximum width of T2, 0.85. Coloration. Head mostly dark; clypeus, antennae, mandible except for the dark brown teeth, and mouthparts light brown. Pronotum light brown; mesoscutum, scutellum, metanotum, metaposnotum, metapleura and propodeum mostly dark brown; legs light reddish brown. Wing membrane hyaline, veins and pterostigma dark brown. Metasoma mostly brown to dark brown. Pilosity. Mostly sparse and conspicuous; upper portion of gena with relatively long setae, their length between 1.5 and 2× diameter of anterior ocellus; pronotum with similar setae, longest ones about as long as 2× ocellar diameter; terga 3–7 with conspicuous erect pilosity, whose length and diameter increase toward apex of metasoma, longest setae almost 3× as long as ocellar diameter; sterna 4–5 also with erect pilosity. Integumental surface. Frons and vertex with conspicuous fine punctation, punctures spaced apart by 1–2 puncture diameters; punctation on pronotum, mesoscutum and scutellum much sparser. Propodeum with transverse carina separating dorsal and posterior surfaces, carina extending ventrally and separating lateral surface from posterior surface as well; dorsal surface bordered laterally by weak longitudinal carina; dorsal surface of propodeum with a deep medial sulcus along entire surface, interrupting transverse carina and extending on to posterior surface. Structure (measurements in mm). Head transverse in frontal view, about 1.7× wider than long (1.1:0.65); malar space as long as ocellar diameter (0.05:0.05); clypeus very short, about 5× wider than long (0.47:0.10); interalveolar distance about 1.6× alveolus diameter (0.11:0.07). F1–F3 slender, respectively about 4.8, 4.4 and 4.0× longer than wide (0.24:0.05; 0.22:0.05; 0.20:0.05); F4 to F10 progressively decreasing in length and in diameter. Inner orbits subparallel, upper and lower interorbital distances subequal (0.41:0.42); eye about 1.4× as long as its maximum width in lateral view (0.73:0.53); distance between posterior ocelli shorter than ocello-orbital distance (0.09:0.14). Legs slender, femur of hind leg slightly longer than tibia (0.64:0.59). Wing venation as for genus, except for vein 1m-cu touching M + Rs basal to their bifurcation. Dorsal surface of propodeum rectangular, about 2× as wide as long (0.43:0.22). Basal portion of 3rd tergum strongly constricted, forming marked step with tergal disc.

Type material. Holotype male, in amber piece DZUP Bur-503. Small, complete, fully winged, well-preserved specimen. The piece has been trimmed to a small size (approximately 7 × 5 × 4 mm). A partial specimen (right wings and hind leg, and part of the abdomen) of a small mayfly is preserved in the same piece.

Etymology. The species is named for the deep medial sulcus on its propodeum, from the Latin sulcus, furrow, and –atus, provided with.