Megachile (Zonomegachile) uncinata, Gonzalez & Griswold & Engel, 2018

Gonzalez, Victor H., Griswold, Terry & Engel, Michael S., 2018, South American Leaf-Cutter Bees (Genus Megachile) Of The Subgenera Rhyssomegachile And Zonomegachile, With Two New Subgenera (Hymenoptera: Megachilidae), Bulletin of the American Museum of Natural History 2018 (425), pp. 1-73 : 1-73

Megachile (Zonomegachile) uncinata ,

new species

Figures 21 , 33 , 34

DIAGNOSIS: This species is known only from the male sex. It can be easily recognized by the follow- ing combination of features: hypostomal tooth posteriorly directed, strongly curved (fig. 33E); protibia with posterior margin carinate; probasitarsus about twice as long as broad, distinctly expanded posteriorly (fig. 33C); and preapical carina of T6 narrow, on middle one third of tergum (fig. 34A). In all other species of Zonomegachile the hypostomal tooth is anteriorly directed, straight, the posterior margin of the protibia is rounded, the probasitarsus is more elongate, parallel-sided, and the preapical carina of T6 is broader, occupying about the median half of the tergum.

DESCRIPTION: Holotype (paratype in parentheses), Male: total body length 11.5 (12.3) mm; forewing length 8.5 (8.5) mm; head width 3.8 (3.9) mm. Head 1.3× wider than long; inner orbits of compound eyes straight or nearly so; intertorular distance 1.3× times torulorbital distance; interocellar distance 2.1× OD, 0.9× ocellocular distance; ocelloccipital distance 3.2× OD, 1.5× ocellocular distance; scape 2.1× longer than broad, pedicel shorter than F1, slightly broader than long, F1 1.1× longer than broad, shorter than F2, remaining flagellomeres longer than broad, distalmost flagellomere slightly compressed and expanded. Clypeus straight or nearly so on distal margin; hypostomal area anteriorly with strong, posteriorly projected tooth, hidden by dense pubescence in frontal view, with distinct cavity posterior to tooth. Procoxa with apical spine long, about 1.5× OD; protibia with posterior margin carinate; probasitarsus expanded, convex on posterior margin, about twice as long as broad; mesobasitarsus 2.5× longer than broad; metabasitarsus 3.5× longer than broad. Preapical carina of T6 on middle onethird of tergum, shallowly emarginate medially, about 3.0× broader than deep, tooth lateral to emargination small, acute (larger and blunt in the paratype). Genital capsule and associated terga and sterna as in figure 34.

Body color black, except: dorsal and ventral surfaces of profemur, and inner surface of protibia yellow; anterior surface of protibia, and meso- and metadistitarsi light reddish brown; protarsi yellowish, slightly darkened on apical podites. Tegula dark brown to black; wings brownish, darker anterior half of marginal cell; pterostigma and veins dark brown.

Pubescence dark grayish brown except: face, gena, hypostomal concavity, inferior margin of mandible, pronotum dorsally, pronotal lobe, anterior margin of mesoscutum, preaxilla, mesoscuto-mesoscutellar suture, metanotum, propodeum posteriorly, outer surfaces of protarsi, discs of T1 and T5, and apical fasciae of T1–T5 and S1–S3 with white setae; profemur basally and inner surfaces of all tarsi with light reddish-brown setae. Hypostomal concavity bordered posteriorly by stiff setae. Procoxa ventrally, near spine, with stiff, thick light reddishbrown setae, apex of spine with tuft of shorter, denser, thinner, light reddish-brown setae; protarsi with dense fringe of short setae along their posterior margin, at most 0.6× width of basitarsus; mesotarsi with sparser, longer fringe of setae than on protarsi, about 3.0× longer than width of mesobasitarsus; posterior surface of metafemur, near dorsal margin, with tuft of keirotrichial setae. Apical fascia on sterna longer and sparser than on terga.

Face and vertex coarsely and densely punctate, punctures contiguous except on vertex behind ocelli; gena superiorly with smaller, shallower punctures than on vertex, punctures becoming coarser inferiorly. Mesoscutum weakly imbricate, shiny, with coarse, larger punctures than on vertex, separated by at most a puncture width on disc; mesoscutellum and axilla with denser punctures than on mesoscutum, nearly contiguous on axilla; mesepisternum alveolate, alveoli larger than punctures on mesoscutum; metepisternum and lateral and posterior surfaces of propodeum strongly imbricate, punctures on metepisternum separated by at most a puncture width, punctures smaller and closer on lateral surface of propodeum, becoming sparser (≥2.0× PW), shallower on posterior surface of propodeum; propodeal triangle microalveolate; metanotum strongly imbricate with smaller, shallower, and denser punctures than on mesoscutellum; legs weakly imbricate to smooth and shiny with coarse punctures on outer surfaces of tibiae. Terga weakly imbricate to smooth and shiny, minutely and sparsely punctate (1.0–3.0× PW), punctures coarser and denser on T5; T6 foveate, with sharp borders among fovea; sterna more strongly imbricate and with sparser punctures than on terga.

Female: Unknown.

HOLOTYPE: ♂, ARG [ Argentina]: Catamarca, Colpes, 15 km S, X-27-72 [27 October 1972], G.E. Bohart/ Zuccagnia punctata (BBSL) .

PARATYPE: 1♂, ARG [ Argentina]: S.D. Estero [Santiago del Estero], Las Termas, X-11-72 [11 October 1972], G.E. Bohart/ Prosopis alba (BBSL) .

ETYMOLOGY: The specific epithet is from the Latin uncīnus meaning “hook,” in reference to the curved, posteriorly directed projection of the hypostomal area that characterizes the male of this species.

FLORAL RECORDS: This species has been collected on flowers of Prosopis alba Griseb. and Zuccania punctata Cav. , both in the family Fabaceae .

COMMENTS: We assigned this species to Zonomegachile based on the presence of a hypostomal projection. However, the shape of the genital capsule and associated sterna does not suggest a close relationship to the other species of the group and it might belong to a different subgenus, pending discovery of the female. For the moment, this is the most conservative placement for the species.

Figures

FIGURE 21. Collection localities for species of Megachile (Zonomegachile).

FIGURE 33. Male holotype of Megachile (Zonomegachile) uncinata Gonzalez, Griswold, and Engel, new species, except paratype in figures C and E. A. facial view. B. Lateral habitus. C. Outer surface of protibia and protarsi.D. Dorsal habitus. E. Detail of hypostomal area showing hook (highlighted in green).

FIGURE 34. Male paratype of Megachile (Zonomegachile) uncinata Gonzalez, Griswold, and Engel, new species. A. Sixth tergum in dorsal view. B, D. Seventh tergum in dorsal and ventral views. C. Fifth sternum. E. Sixth sternum. F. Eighth sternum. G–I. Genital capsule in dorsal, ventral, and lateral views.