Orasema bakeri Gahan

Baker, Austin J. & Heraty, John M., 2020, The New World ant parasitoid genus Orasema (Hymenoptera: Eucharitidae), Zootaxa 4888 (1), pp. 1-84 : 27-29

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Orasema bakeri Gahan


Orasema bakeri Gahan


( Fig. 13 View FIGURE 13 )

Orasema bakeri Gahan 1940: 452–453 .

Diagnosis. Distinguished from other members of the bakeri group by the following combination of characters: mesoscutal midlobe and lateral lobes reticulate without any depressions ( Fig. 13F View FIGURE 13 ), petiole relatively long (PTL:PTW = 0.8–1.3 in females, 3.5–4.9 in males), male antenna with setae long and broadly curved anteriorly ( Fig. 13E View FIGURE 13 ), and body size larger on average.

This species is difficult to diagnose from O. dubitata but is generally less violaceous and has a larger average body size.

Description. Female. Length 3.0– 3.5 mm ( Fig. 13A View FIGURE 13 ). Color. Head and mesosoma blue-green iridescent occasionally with violaceous patches. Scape, pedicle, and anellus pale brown; maxilla and labium pale brown. Tibiae light brown. Fore wing venation pale brown, nearly white. Head ( Fig. 13B View FIGURE 13 ). Head in frontal view subtriangular; HW:HH = 1.1–1.3; scrobal depression shallow, laterally rounded, with transverse striae; eyes bare, IOD:EH = 1.5–1.9; MS:EH = 0.7–1.0; supraclypeal area slightly broader than long, weakly reticulate; epistomal sulcus distinct and sharply defined; anteclypeus distinct, nearly straight. Palpal formula 3:2. Occiput with dorsal margin evenly rounded. Pedicel globose, broader than F1. FL:HH = 0.9–1.1; F2L:F2W = 1.3–2.0, F2L:F3L = 1.1–1.5 ( Fig. 13D View FIGURE 13 ). Mesosoma ( Fig. 13C, F View FIGURE 13 ). ML:MH = 1.2–1.4. Mesoscutal midlobe bare; lateral lobe reticulate to nearly smooth; notauli deep. Axilla reticulate, dorsally rounded, on roughly same plane as mesoscutellum; scutoscutellar sulcus narrow, regularly foveate, broadly separated from transscutal articulation; mesoscutellar disc as long as broad, reticulate; frenal line as smooth band; axillular sulcus indicated by a weak longitudinal carina; axillula reticulate. Propodeal disc broadly rounded, without depression or carina ( Fig. 13G View FIGURE 13 ); reticulate; callus reticulate, bare; callar nib absent. Propleuron strongly convex, protruding ventrally. Postpectal carina weak. Upper and lower mesepimeron reticulate; transepimeral sulcus distinct. Metepisternum laterally reticulate. HCL:HCW = 1.4–2.0; HFL:HFW = 4.6–6.0, evenly covered with short, dense setae. FWL:FWW = 2.1–2.5, FWL:ML = 1.9–2.2; fore wing with basal third bare, costal cell sparsely setose, wing disc with minute sparse setae; marginal fringe short to absent; submarginal vein with minute setae; marginal vein with sparse minute setae; stigmal vein about twice as long as broad, perpendicular to anterior wing margin; postmarginal vein longer than stigmal vein. Metasoma. Petiole cylindrical, linear in profile, PTL:PTW = 0.8–1.3, PTL:HCL = 0.5–0.8, reticulate, lateral margin rounded, ventral sulcus absent. Ovipositor with subapical carina present; second (dorsal) valvula with 6 or 7 annuli that are narrowly separated dorsally, the carinae coalescing.

Male. Length 2.4–3.0 mm. HW:HH = 1.2–1.3; FL:HH = 1.2–1.3, F2L:F2W = 1.0–1.4 ( Fig. 13E View FIGURE 13 ). Tibiae light brown. PTL:PTW = 3.5–4.9, PTL:HCL = 1.3–1.7.

Hosts. Unknown.

Plant associates. Swept from Fabaceae and Chrysothamnus sp. ( Asteraceae ) in Arizona, Larrea sp. ( Zygophyllaceae ) in New Mexico, Heracleum mantegazzianum Sommier & Levier ( Apiaceae ) in Colorado ( Gahan 1940).

Distribution ( Fig. 11 View FIGURE 11 ). Mexico: DF; United States: AZ, CO, ID, MN, NE, NM, OK, TX, UT, WY. Collected June–August.

Material Examined. Holotype. UNITED STATES. Colorado: Larimer Co., Fort Collins , 40 ° 34’58”N, 105 ° 05’5”W, 13.vi.1895, C.F. Baker, 1563 [♀, deposited in USNM: USNMENT01524341, type images: http:// n 2t.net/ark:/65665/3e5a194bb-aca0-4751-8a0c-1def5010f856] GoogleMaps . Allotype. UNITED STATES. Colorado: Larimer Co., Fort Collins, 40 ° 34’58”N, 105 ° 05’5”W, 13.vi.1895, C.F. Baker, 1563 [³, USNM: UCRCENT00247804]. GoogleMaps Other paratypes. UNITED STATES. Arizona: Pinal Co. , Oracle, 32 ° 36’39”N, 110 ° 46’14”W, 7.vi.1898, Hubbard & Schwarz [1♀, USNM: UCRCENT00247813]. GoogleMaps Colorado: Archuleta Co. , Pagosa Springs, 37 ° 15’55”N, 107 ° 00’46”W, C.F.Baker [1³, USNM:UCRCENT00247812]. Larimer Co. , Fort Collins , 40 ° 34’58”N, 105 ° 05’5”W, 13.vi.1895, C.F. Baker, 1563 [6♀, USNM: UCRCENT00247805–10]; vi, wild parsnip bloom, 1086 [1♀, USNM: UCRCENT00247811] GoogleMaps . Additional material examined. 49 specimens, see supplementary material. GenBank sequences. UCRCENT00411576 (D4097): 18S ( KR632468.1 ) , 28S D2 ( KR632393.1 ) , 28S D3–5 ( KR632432.1 ) , COI-BC ( KR733117.1 ) , COI-NJ ( KR733149.1 ) .

Discussion. This species is morphologically similar to O. dubitata , O. taii , and O. polymyrmex . While there is some molecular support for O. dubitata and O. taii as separate species, O. polymyrmex failed sequencing attempts. Due to the cryptic nature of this 4-species complex, it requires more thorough molecular sequencing across populations in separate geographic areas to be able to confidently associate morphological differences with phylogenetic differences.


USA, Washington D.C., National Museum of Natural History, [formerly, United States National Museum]














Orasema bakeri Gahan

Baker, Austin J. & Heraty, John M. 2020

Orasema bakeri

Gahan, A. B. 1940: 453