Megachile (Rhyssomegachile) kartaboensis Mitchell

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 (Rhyssomegachile) kartaboensis Mitchell

Figure 4D, E , 14 , 16

Megachile kartaboensis Mitchell, 1930: 299 (holotype ♀, examined, MCZ 16212: Kartabo, Guyana). Raw, 2002: 33 (placement in Rhyssomegachile Mitchell ).

DIAGNOSIS: This species is known only from the female holotype. It can be easily recognized by the following combination of features: preoccipital carina behind gena only; mesoscutum with contiguous punctures on disc; and ventral surface of mesepisternum and outer surfaces of pro- and mesotibiae and basitarsi covered with corkscrewlike setae (fig. 4D, E). It shares with M. simillima the mesoscutum contiguously punctate, but it can be distinguished by its larger body size, the corkscrew-like setae on the ventral surface of mesepisternum and fore- and middle legs (setae thick and apically curved in M. simillima ), and finer punctation on clypeus and supraclypeal area. The corkscrewlike setae on the ventral surface of the mesepisternum and outer surfaces of the pro- and mesotibiae and basitarsi are also present in M. urbana . However, in that species the punctures on the disc of the mesoscutum are distinctly spaced, not contiguous, separated by 1–2× a puncture width.

REDESCRIPTION: Female: total body length 10.9 mm; forewing length 8.8 mm; head width 4.1 mm. Head 1.3× wider than long; inner orbits of compound eyes parallel or nearly so; intertorular distance 1.4× torulorbital distance; interocellar distance 1.3× OD, 0.7× ocellocular distance; ocelloccipital distance 2.1× OD, 1.1× ocellocular distance; clypeus with distal margin entire, slightly incurved medially; scape 3.2× longer than broad, pedicel 1.2× longer than broad, F1 about as long as F2, slightly broader than long as in F2–F9, distalmost flagellomere longest, 1.6× longer than broad. Mesobasitarsus slightly broader and shorter than mesotibia; metatibia 2.9× longer than broad; metabasitarsus 2.8× longer than broad, shorter (0.8×) and narrower (0.9×) than metatibia.

Body color black, except dark reddish brown on legs and basal sterna. Wings brownish, darker on radial cell apically, first submarginal, and marginal cells; veins and pterostigma dark brown.

Pubescence brownish gray to dark brown, except white on: paraocular area inferiorly, sides of clypeus and supraclypeal area, base of mandible, gena, hypostomal area, anterior margin of mesoscutum, distal margin of mesoscutellum, metanotum, sides of mesepisternum, metepisternum, propodeum, and S2–S5 except laterally. Ventral surface of mesepisternum and fore- and middle legs with coxae, trochanters, base of femora, and outer surfaces of tibiae and basitarsi densely covered by corkscrewlike setae. Discs of T2–T5 sparsely covered with short (~0.3× OD), appressed setae, laterally and on discs of T4 and T5 with scattered, erect or semierect setae; T6 with shorter, denser appressed setae, without erect setae.

Face and vertex coarsely and contiguously punctate with surface among punctures angular, except clypeus and supraclypeal area with finer, sparser (≤1.0× PW) punctures, surface among them rounded, with integument smooth and shiny; gena with shallower punctures than on vertex, punctures stronger and closer on lower gena and hypostomal area; outer surface of mandible apically, above outer ridge, with carinae somewhat dull, minutely roughened. Pronotum weakly imbricate with smaller, shallower, sparser (≤1.0× PW) punctures than on mesoscutum; mesoscutum, mesoscutellum as on vertex; axilla dorsally with integument weakly imbricate among sparser punctures than on mesoscutellum; mesepisternum smooth and shiny with larger (1.5×), sparser (≤1.0× PW) punctures than on mesoscutum, punctures becoming smaller and closer dorsally; metepisternum and propodeum imbricate, with oval, faint, and spaced (≤1.0× PW) punctures on metepisternum, about as large as those on mesoscutum; lateral surface of propodeum with smaller, fainter, closer punctures than on metepisternum, posterior surface of propodeum with widely separated (2.0–4.0× PW) punctures; metanotum finely and minutely (≤1.0× PW) punctate; legs weakly imbricate to smooth and shiny, coarsely and densely (≤1.0× PW) punctate, punctures larger and sparser on hind legs. Terga minutely and densely punctate, punctures contiguous on discs, slightly spaced laterally, at most half a puncture width of those on mesoscutum, integument otherwise weakly imbricate to smooth and shiny; sterna strongly imbricate, coarsely punctate, punctures smaller and closer on basal sterna.

Male: Unknown.

HOLOTYPE: ♀, Kartabo, B.G., Jul, Aug. 1920, W.M. Wheeler /MCZ-ENT 00016212/ Megachile kartaboensis Mitchell ♀, Type 16212 ( MCZ).

Figures

FIGURE 4. Some morphological features used in the phylogenetic analysis. A–C. Punctation of mesoscutum. D–F. Pubescence of outer surface of female protarsi. A. Megachile (Rhyssomegachile) simillima Smith (female holotype). B. M. (Aporiochile) tricosa Cockerell (male holotype). C. M. (Rhyssomegachile) guayaqui Schrottky (female neotype). D, E. M. (Rhyssomegachile) kartaboensis Mitchell (female holotype). F. M. (Zonomegachile) moderata Smith (female holotype).

FIGURE 14. Collection localities for species of Megachile (Rhyssomegachile).

FIGURE 16. Female holotype of Megachile (Rhyssomegachile) kartaboensis Mitchell. A. facial view. B. Detail of clypeus and supraclypeal area. C. Lateral habitus. D. Dorsal habitus.