Oligochlora semirugosa Engel, 2009

Engel, Michael, 2009, Two New Halictine Bees in Miocene Amber from the Dominican Republic (Hymenoptera, Halictidae), ZooKeys 29 (29), pp. 1-12 : 4-6

Oligochlora semirugosa Engel , sp. n.

urn:lsid:zoobank.org:act:8806981A-AC4A-4772-AD63-A508D925A7DA

Figs 1–2

Holotype. ♀, KU-DR-21 (Fig. 1); amber from the Dominican Republic (specific mine unknown), Early Miocene (Burdigalian); Fossil Insect Collection , Division of Entomology , University of Kansas Natural History Museum, Lawrence, Kansas, USA.

Diagnosis. The new species is apparently most similar to O. micheneri Engel as evidenced by the short basal area of the propodeum which is granular and bearing minute striae along the basal margin. It can be distinguished by the rugulose integument of the genae, the dense punctation of the mesoscutum (except medially), and the obtuse dorsolateral angle of the pronotum.

Description. Female: Total body length 7.9 mm; forewing length 6.3 mm. Head wider than long (length 1.7 mm, width 1.8 mm); upper interorbital distance 0.83 mm; lower interorbital distance 0.73 mm. Clypeus not protruding, apical half below lower tangent of compound eyes; epistomal sulcus forming obtuse angle (Fig. 2). Preoccipital ridge rounded. Pronotal dorsolateral angle obtuse, dorsal ridge carinate; lateral angle sharply angled but apparently not carinate; tegula oval; intertegular distance 1.6 mm. Forewing with basal vein weakly arched, distad cu-a by about 4.5 times vein width; 1rs-m distad 1m-cu by about vein width; 2rs-m gently arcuate, distad 2m-cu by about eight times vein width; pterostigma relatively slender; marginal cell apex minutely truncate and feebly appendiculate; first submarginal cell longer than combined lengths of second and third submarginal cells; second submarginal cell narrow, not narrowed anteriorly; length of anterior border of second submarginal cell along Rs shorter than anterior border of third submarginal cell; length of anterior border of third submarginal cell along Rs about one-half posterior border of third submarginal cell. Hind wing with distal hamuli arranged 3-1-3. Inner metatibial spur with three branches, not including apical portion of rachis. Medioapical slit of pseudopygidial area deep.

Clypeus granular with coarse, shallow punctures separated by less than a puncture width (Fig. 2), such sculpturing on majority of supraclypeal area and face below level of antennal toruli; punctures gradually becoming smaller, more well defined, and more closely packed by level of antennal toruli such that on face above antennae integument is covered with small, contiguous punctures; punctures become more separated by ocellocular area and vertex, separated by a puncture width or less, integument between punctures granulose; gena granular with scattered small, shallow punctures, and with transverse weak rugae. Mesosoma granular throughout; mesoscutum with small contiguous punctures except on central disc punctures become more widely spaced, separated by 0.5–2 times a puncture width; median and parapsidal lines deeply impressed; mesoscutellum

Figures |–2. Photomicrographs of holotype female of Oligochlora semirugosa sp. n. (KU-DR-21). | Dorsolateral oblique aspect of holotype 2 Facial aspect.

with small punctures anteriorly separated by a puncture width or less, gradually becoming more closely packed posteriorly until contiguous and irregular such that integument appears weakly rugulose; metanotum longitudinally rugulose, integument between rugae granular and impunctate; basal area of propodeum granular with short striae along basal margin, striae not reaching to one-third length of basal area, lateral and posterior surfaces of propodeum granular and apparently impunctate (difficult to discern posterior and lat- eral surfaces); pleura coarsely punctured, punctures contiguous. Metasoma granular with small, shallow punctures separated by less than a puncture width, punctures posteriorly on more apical terga slightly elongate and forming weak longitudinal rugae, punctures fade by apical margins such that margins are strongly imbricate and impunctate; sterna apparently strongly imbricate with scattered punctures (direct view of sterna challenging).

Integument generally dull, dark metallic green (where preserved) except mandible, labrum, labiomaxillary complex, apical portion of clypeus, antenna, and tegula dark brown; legs brown. Wing membranes hyaline; veins dark brown. Metasomal terga dark metallic green, with some brighter green highlights in places; pseudopygidial area dark brown; sterna dark brown with weaker metallic green highlights.

Pubescence generally pale and scattered, slightly fuscous on inner surfaces of meso- and metatarsi; those setae on face, mesosoma, and metasoma generally simple, short to moderate in length, and erect to suberect. Scopal setae on metafemur elongate and apically plumose, moderately dense; setae on inner surface of metatibia elongate (almost as long as metatibial spurs), numerous (but not dense) and largely simple except a few in basal two-thirds apically palmate; those on outer surface somewhat shorter, more dense, thicker, and simple.

Etymology. The specific epithet is a combination of the Latin prefix semi - (meaning, “half” or “partial”) and rugosus (meaning, “wrinkled”).