Ruizantheda nigra Coelho & Engel 2018, n. sp.
Creators: name: Coelho, Beatriz W. T.
name: Engel, Michael S.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hymenoptera
Halictidae
Ruizantheda
Ruizantheda nigra

description: Ruizantheda nigra n. sp.
(Figures 3, 19, 20, 26, 28, 31, 42)
Diagnosis. Mesobasitarsus short, about one-third length of mesotibia, subquadrate and flattened, with small ventral keel at apex (Fig. 19); apical margin of S4 deeply emarginate and bent ventrally, surrounded by many plumose setae (Fig. 20); S5 with extremely-large, U-shaped gradulus (Fig. 20); lower lamella of bilobed penis valve forming lateral lobe curved upwards (Fig. 42). These traits are distinct autapomorphies for this species. Other diagnostic characters include: head and mesosoma blackish with faint green highlights; mesoscutum with abundant dark setae; head as long as wide giving an elongate appearance (Fig. 3).
Description. Male: Size. Length approximately 11.0 mm. Forewing length 9.0 mm. Intertegular distance 1.6 mm.
Colour. Head and mesosoma blackish with faint green highlights on supraclypeal area, mesoscutellum, metanotum, and posterior surface of propodeum. About apical one third of clypeus with yellow transverse band.
Mandible brown with reddish apex. Labral basal area brownish-yellow. Antenna dark brown, flagellum lighter below than above. Legs dark brown, but yellow on extremities of profemur and basal region of probasitarsus. Metasoma dark brown, bases of T1–6 with faint green highlights. Pygidial plate brown.
Pubescence. Compound eyes with dark setae, longer than ocellar diameter (approximately 1.3×). Face with long, plumose, dark setae, white setae around torulus. Lower paraocular area with strip of short, plumose, white setae along inner margin of compound eye. Anterior half of upper gena with long, plumose, dark setae, such setae white elsewhere. Mesosoma with dark setae, except anterior margin of mesoscutum with white setae. Legs with whitish setae, except profemur with some dark setae, inner surface of tibiae and tarsus with yellowish setae. Discs of T2–5 with semi decumbent to decumbent setae of variable length. Posterior marginal zones of T3–5 with many short, simple, yellowish, appressed setae. Apicolateral lobes of S4 with tuft of branched setae and about 12 stout, simple, recurved setae on margin; concavity of S4 surrounded by many plumose setae. S5 with conspicuous patch of short, decumbent setae inside U-shaped gradulus; apical margin with band of plumose, semi-decumbent setae, slightly longer than those inside gradulus.
Structure. Head approximately as long as wide (Fig. 3). Ratio of upper to lower interocular distance about 1.2. Malar area linear. Mandible simple. Labral distal process in form of a minute inverted triangle. Epistomal sulcus forming obtuse angle and slightly rounded. Clypeus projecting approximately two thirds of its length below lower orbital tangent. Ocellocular area concave. Vertex expanded behind ocelli. Frons slightly depressed. Preoccipital ridge rounded. Antenna unmodified, F2 about 2.0× length of F1. Profemur swollen. Mesofemur greatly swollen, ventrally flattened; mesotibia slightly swollen with flat, minutely ridged ventral area and small distal tooth on outer surface; mesobasitarsus similar in shape to other tarsi, short, about one-third length of mesotibia, subquadrate and flattened, with small, distal, and ventral keel (Fig. 19). Hind leg unmodified. S4 shortened medially, partially hidden under S3 and bent ventrally (Fig. 26), with transverse median depression and apical margin deeply emarginated (Fig. 20). Apical margin of S5 very shallowly emarginate, with extremely-large, U-shaped gradulus almost reaching apical margin (Fig. 20). Gradulus of S6 nearly interrupted medially, present only as a very thin line (Fig. 28). S7 with median apical process short, without setae. S8 with median apical process broad, apical margin bearing lateral lobes membranous, separated by a short, thin, sclerotized surface and, rounded lobe medially (Fig. 31). Pygidial plate oval, slightly truncate apically.
Genitalia (Fig 42). Basal region of gonobase with W-shaped in ventral view. Gonocoxae with outer margins divergent, convex near apex; inner dorsal margins progressively divergent, at about midpoint becoming slightly curved and much more divergent. Basal region of gonostylus with rvl sclerotized, long, more than one-half length of gonocoxite, rounded apically, with many rows of simple setae slightly curved upwards at extremity, not overlapping those of opposing gonostylus, and setae on half of inner lateral margin; with broad median projection formed by a sclerotized area that partially borders a translucent and inflated region; inner lobe present. Mgl crescent-shaped with outer surface expanded medially, and with scattered short setae. Ogp large, ending before apex of mgl, with many erect setae arising at juncture of ogp with mgl; outer margin less sclerotized, extending to ventral region and laterally forming an inflated, circular area with cuticular wrinkles; clump of setae at base of ogp absent. Penis valve strongly arched in lateral view; with strong, main, central dorsal ridge; apex pointed and long; outer lateral expansion bilobed with lower lamella forming lateral lobe curved upwards and without projection posteriorly; prong narrow, extending past volsella posteriorly. Volsella medio-apical margin strongly emarginate; basal region slightly rounded.
Sculpture. Upper paraocular area and frons densely punctate, with fine, contiguous punctures and setal bases intermixed, separated by 4–6 PD, surface finely roughened near median ocellus. Lower paraocular area with coarse punctures separated by 1–3 PD. Supraclypeal area with punctures separated by 1–2 PD laterally, becoming sparser centrally in lower half. Disc of clypeus with coarse punctures separated by 2–4 PD. Face with surface between punctures microreticulate. Mesoscutum with setal bases separated by 4–6 PD in central area. Mesoscutellum with coarse setal bases denser at sides and posterior margin (1–2 PD), becoming sparser centrally. Pre-episternum with setal bases separated by 3–4 PD. Mesepisternum with setal bases separated by 3–6 PD. Metapostnotum with triangular area defined by microareolate sculpture. Surface between setal bases reticulate throughout mesosoma. Discs of T2–3 with fine punctures separated by about 2–3 PD, punctation reaching apical margin, surface reticulate, slightly finer than remainder of body.
Distribution. Ruizantheda nigra n. sp. is presently known only from Bolivia.
Type material. Holotype male (USNM), “ BOLIVIA \ Br. Ichilo R. \ Rain Forest \ Oct.15:16, 1966\ B.&K.
Burks” and “ HOLOTYPE \ Ruizantheda nigra \Coelho & Engel” [red label]. Head, antennae, left mesofemur, mesotibia, and mesotarsus glued to board.
Comments. Among the six species studied, R. nigra has the longest apex to the penis valve. Etymology. This specific epithet is taken from the Latin nigra, meaning “black” and a reference to the general colour of the integument.
description: Published as part of Coelho, Beatriz W. T. & Engel, Michael S., 2018, A new group of species within the bee genus Ruizantheda, with a revised key to the males of the genus (Hymenoptera: Halictidae: Caenohalictini), pp. 513-532 in Zootaxa 4415 (3) on pages 515-517, DOI: 10.11646/zootaxa.4415.3.6, http://zenodo.org/record/1242185