Nomada augustiana Mitchell

Droege, Sam, Rightmyer, Molly G., Sheffield, Cory S. & Brady, Seán G., 2010, New synonymies in the bee genus Nomada from North America (Hymenoptera: Apidae), Zootaxa 2661, pp. 1-32 : 4-5

Nomada augustiana Mitchell

Figures 1–3 , 13, 14 , 23

Nomada augustiana Mitchell 1962: 402 –403. [Holotype: U.S. National Museum of Natural History (on indefinite loan from North Carolina State University), Ψ; label data: “[ USA] Augusta, Georgia, Richmond Co., Apr [April] 1 1959/ / Salix // HOLOTYPE Nomada augustiana Mitchell [red label]// USNM ENT 0 0 533881 [yellow barcode label]”].

Nomada indusata Mitchell 1962: 418 –419. [Holotype: U.S. National Museum of Natural History (on indefinite loan from North Carolina State University, ♂; label data: “[ USA] Wendell NC [North Carolina], TB Mitchell, III 26 ’25 [26 March 1925]// Amelanchier // HOLOTYPE Nomada indusata Mitchell [red label]// Type No. 75220 U.S. N.M. [red label]// USNM ENT 0 0 533936 [yellow barcode label]”] new synonymy.

Diagnosis. Females can be differentiated from other North American Nomada by the following combination of characters: head and mesosoma with limited amounts of black integumental color ( Fig. 1 ); scutellum entirely yellow on its dorsal surface (shading to orange near metanotum) ( Fig. 1 ); hind tibia at outer apical margin with three to four long, red, stout spine-like hairs that clearly extend beyond the surrounding finer white hairs (three present on one hind leg, four on the other leg in the holotype specimen—based on trends in other Nomada , it is likely that other specimens of this species could have a slightly greater number of such stout red spine-like hairs present) ( Fig. 13 ); and T2–T3 each with transverse, medially-interrupted, yellow maculations ( Fig. 3 ). Females of N. obliterata Cresson have a similar integumental color pattern, but are readily separated from N. augustiana by the extensive black integumental color on the median portion of the propodeal triangle; shorter stout, red spine-like hairs on hind tibia (about the same length as the surrounding white hairs); and only two submarginal cells in the forewing (rarely, some specimens of N. obliterata have three). Nomada armatella Cockerell can be differentiated from N. augustiana by the black median longitudinal stripe present on the mesoscutum and propodeum; very thin white spine-like hairs on the outer apical margin of the hind tibia; and uninterrupted maculations of T2 and T3 (or, if medially-interrupted, then this interruption is extremely narrow, forming a thin longitudinal, linear gap). Nomada bethunei is also somewhat similar in the color pattern of its integument, but lacks the clear yellow integument on the scutellum (however, some individuals of N. bethunei have an ill-defined orangish area on this sclerite) ( Fig. 5); also, T1 usually lacks yellow maculations ( Fig. 5), although the holotype of N. bethunei from Wisconsin has broadlyinterrupted, narrow yellow maculations ( N. augustiana with relatively broad, medially-interrupted yellow maculations). Nomada bethunei additionally has only very short (far shorter than the surrounding white hairs), stout, red, spine-like hairs on the outer apical margin of the hind tibia ( Fig. 15 ).

Males of N. augustiana are differentiated by the following combination of characters: mesoscutum with integument more than fifty percent red ( Fig. 2 ); scutellum integument almost entirely yellow ( Fig. 2 ); and hind tibia at outer apical margin with three to five white or transparent, long, stout, spine-like hairs (clearly longer than the surrounding white hairs) ( Fig. 14 ). Males of N. obliterata have a similar color pattern on their integument but can be differentiated from N. augustiana by the color of the mesoscutum (entirely black or only with two short, red, submedian longitudinal maculations). In addition, in N. obliterata the hind tibia has reddish, stout, spine-like hairs that are only about the same length as the surrounding white hairs. Males of N. bethunei have a similar color pattern as N. augustiana , but in the former species the scutellum integument usually lacks any yellow color (a few specimens have a diffuse orange patch) ( Fig. 6), and the flagellar segments lack or only have limited patches of minute hairs present on the anterior surface (when antenna positioned dorsally). In N. augustiana , the flagellar segments are densely covered with short hairs that are clearly visible at 40– 60 X magnification ( Fig. 23).

Distribution. Nomada augustiana is a rare southern species.

Variation. The only female known to us is the holotype specimen.

Material examined. We examined 10 specimens from GA and NC (Appendix).

Comments. We did not obtain DNA barcoding data for this species. While Mitchell only lists the holotype in his original description and we have seen no other similar specimens, the gender association seems relatively straightforward; in fact, both the holotype of N. augustiana and a specimen of N. indusata were collected on the same date, genus of tree ( Salix ), and locality by the same collector. Even prior to this realization it was clear from inspection that the hair pattern of the male hind tibia was simply a paler version of the long, evenly-spaced, spine-like hairs of the female, and we found other similarities between the two sexes in their body size, vase-shaped scape, relatively hairy flagellar segments of the antenna, and relative lengths of F1 and F2. Interestingly, despite the low number of specimens available for this species it seems fairly reasonable to assume that it is associated with wetland areas. Labels on the Thomasville, Georgia specimens indicate they were collected in a marsh and the Augusta, Georgia specimens were collected off of Salix , a wetland tree. A search for more specimens of this species may be rewarded by collecting near blooming Salix or around the nest sites of southern coastal plain Andrena species who favor Salix pollen (e.g., Andrena macoupinensis Robertson ).

Figures

FIGURES 1 – 3. Nomada augustiana. Fig. 1. Dorsal habitus of female holotype. Fig. 2. Dorsal habitus of male. Fig. 3. Metasoma of female holotype.

FIGURES 13 – 18. Outer apical surface of hind tibia. Figs. 13, 14. Nomada augustiana. Fig. 13. Female holotype. Fig. 14. Male. Figs. 15, 16. Nomada bethunei. Fig. 15 Female. Fig. 16. Male. Figs. 17, 18. Nomada fragariae. Fig. 17. Female. Fig. 18. Male.