Orasema polymyrmex, Baker & Heraty, 2020

Baker, Austin J. & Heraty, John M., 2020, The New World ant parasitoid genus Orasema (Hymenoptera: Eucharitidae), Zootaxa 4888 (1), pp. 1-84 : 32-34

publication ID


publication LSID




persistent identifier


treatment provided by


scientific name

Orasema polymyrmex

n. sp.

Orasema polymyrmex n. sp.


( Fig. 15 View FIGURE 15 )

Diagnosis. Distinguished from other members of the bakeri group by the following combination of characters: male petiole short (PTL:PTW = 0.8–1.2), female mesoscutellum often with a medial depression that is differently colored ( Fig. 15F View FIGURE 15 ), fore wing with marginal fringe, mesoscutal midlobe rarely with an indication of a depression ( Fig. 15F View FIGURE 15 ), mesoscutal lateral lobes reticulate ( Fig. 15F View FIGURE 15 ), and clypeal margin generally broadly rounded ( Fig. 15B View FIGURE 15 ).

This species is most similar to O. bakeri and O. dubitata , but is distinguished by the short male petiole and scutellar depression.

Description. Female. Length 2.3–3.4 mm ( Fig. 15A View FIGURE 15 ). Color. Head and mesosoma dark blue-green. Scape yellow; pedicel and anellus light brown. Maxilla and labium light brown. Tibiae yellow. Fore wing venation pale brown to white. Head ( Fig. 15B View FIGURE 15 ). Head in frontal view subtriangular; HW:HH = 1.1–1.2; scrobal depression shallow, laterally rounded, reticulate; eyes bare, IOD:EH = 1.5–1.9; MS:EH = 0.7–1.0; supraclypeal area slightly broader than long, mostly reticulate, becoming smooth medially; epistomal sulcus narrow but shallow; anteclypeus distinct, broadly rounded. Palpal formula 3:2. Occiput with dorsal margin evenly rounded. Pedicel globose, as broad as F1. FL:HH = 0.9–1.1; F2L:F2W = 1.1–1.6, F2L:F3L = 1.1–1.6 ( Fig. 15D View FIGURE 15 ). Mesosoma ( Fig. 15C, F View FIGURE 15 ). ML:MH = 1.1– 1.3. Mesoscutal midlobe bare; lateral lobe reticulate; notauli shallow. Axilla reticulate, dorsally rounded, on roughly same plane as mesoscutellum; scutoscutellar sulcus broad, irregularly foveate, broadly separated from transscutal articulation; mesoscutellar disc as long as broad, reticulate, often with a median depression having a lighter color; frenal line present as a short smooth line; axillular sulcus indicated by a weak longitudinal carina; axillula reticulate to areolate-reticulate. Propodeal disc broadly rounded, without depression or carina, slightly rugose medially ( Fig. 15G View FIGURE 15 ); callus reticulate, bare; callar nib absent. Propleuron convex. Postpectal carina weak. Upper and lower mesepimeron reticulate; transepimeral sulcus weakly impressed. Metepisternum laterally reticulate. HCL:HCW = 1.6–2.0; HFL:HFW = 4.2–5.3, evenly covered with short, dense setae. FWL:FWW = 2.3–2.8, FWL:ML = 2.0–2.3; fore wing with basal third bare, including speculum, wing disc with minute sparse setae; marginal fringe relatively long; submarginal vein and marginal vein with minute setae; stigmal vein about twice as long as broad, slightly angled toward wing apex; postmarginal vein longer than stigmal vein. Metasoma. Petiole broad, linear in profile, PTL:PTW = 0.6–1.5, PTL:HCL = 0.4–0.8, areolate-reticulate, lateral margin with longitudinal carina continuous with basal flange, ventral sulcus absent. Subapical carina present; second (dorsal) valvula with 8–10 annuli that are narrowly separated dorsally, the carinae coalescing.

Male. Length 2.0– 2.5 mm. HW:HH = 1.1–1.3; FL:HH = 1.1–1.4, F2L:F2W = 1.3–1.6 ( Fig. 15E View FIGURE 15 ). Tibiae yellow. PTL:PTW = 0.8–2.7, PTL:HCL = 0.5–1.4.

Hosts. Collected from a nest of Pheidole sp. in Jalisco and Solenopsis sp. in Neuvo Leon. In the Jalisco series of specimens, there is one damaged specimen of Tetramorium sp. pinned with O. polymyrmex (UCRCENT00416802); given that this would be the only instance of Tetramorium parasitism in Orasema , it seems unlikely that this is a true host and more likely that it was collected in the Pheidole nest as well.

Plant associates. Swept from acacia-thorn scrub and oak-acacia grassland.

Distribution ( Fig. 11 View FIGURE 11 ). El Salvador: CU, LI; Guatemala: JA; Honduras: AT; Mexico: CM, CL, GR, HG, JA, MI, NL, OA, TM, VE. Collected April–August, November.

Material Examined. Holotype. MEXICO. Oaxaca: 5.0 Km NW Jct 135/195, 1783m, 17 ° 19’8”N, 96 ° 55’39”W, 20.vii.1987, Heraty, oak-Acacia woodland [♀, deposited in UCRC: UCRCENT00311872] GoogleMaps . Paratypes. MEXICO. Campeche: Cd. Del Carmen , 18 ° 39’11”N, 91° 47’34”W, 30.vii.1984, G. Gordh [1♀, UCRC: UCRCENT00435193] GoogleMaps .

Colima: Manzanillo, 19°05’18”N, 104°18’31”W, 31.vii.1965, H.E. Evans GoogleMaps [1?, MCZ: UCRCENT00322662]. 4 mi. W Chilpancingo, 17 ° 32’24”N, 99 ° 33’36”W, 15.vii.1984, J.B Woolley GoogleMaps [1♀, TAMU: UCRCENT00243107]. 4.5 mi NW El Ocotito , 690m, 17 ° 17’7”N, 99 ° 34’1”W, 7.vii.1987, Woolley and Zolnerowich, 87/018 [1♀, TAMU: UCRCENT00243102] GoogleMaps . Hidalgo: Guanajuato, 2 mi W Dolores, 21 ° 09’0”N, 100 ° 57’36”W, 5.vii.1985, J. Woolley and G. Zolnerowich, 85/026 [1♀, TAMU: UCRCENT00243105]. 2mi. W Dolores, 21 ° 09’0”N, 100 ° 57’36”W, 5.vii.1985, J.Woolley and G. Zolnerowich, 85/026 [1♀, TAMU: UCRCENT00243106]. Chapala , 20°17’46”N, 103°11’28”W, 21.iv.1977, W.F. Barr [1♀, WFBM: UCRCENT00403625] GoogleMaps . Jalisco: Cocula, 1348m, 20 ° 21’55”N, 103 ° 49’22”W, xi.1923, W.M.Mann GoogleMaps [8³ 1♀ 6?, USNM:UCRCENT00416796–810]. Plan de Barrancas , 21°03’29”N, 104°12’37”W, 3.v.1953, R.C. Bechtel & E.I. Schlinger GoogleMaps [1♀, EMEC: UCRCENT00404885] GoogleMaps . Michoacan: 11 mi. E Apatzingan, 19 ° 02’44”N, 102 ° 12’54”W, 20.viii.1954, E.G. Linsley, J.W. MacSwain & R.F. Smith GoogleMaps [2♀, EMEC: UCRCENT00404877–78]. 30 mi S of Neuva Italia , 18 ° 34’48”N, 102 ° 04’48”W, 8.viii.1978, Plitt & Schaffner [1♀, TAMU: UCRCENT00243222] GoogleMaps . Nuevo Leon: Monterrey, 540m, 25 ° 40’0”N, 100 ° 19’0”W, 20.viii.1995, A. Gonzalez, Solenopsis nest GoogleMaps [2♀, UCRC: UCRCENT00278213, UCRCENT00278215]. 11 mi. n. Matias Rome-ro, 17 ° 01’48”N, 95 ° 01’48”W, 6.vii.1971, Clark, Murray, Hart, Schaffner GoogleMaps [1♀, TAMU: UCRCENT00426201]. 46.8 km E Potchula, 24m, 15 ° 49’12”N, 96 ° 03’45”W, 13.vii.1987, J. Heraty, Acacia-thorn scr. [4♀, UCRC: UCRCENT00311870, UCRCENT00311878–79, TAMU: UCRCENT00243103] GoogleMaps . Oaxaca: Temascal , 43m, 18 ° 14’28”N, 96 ° 24’9”W, 30.vi.1964, A.G. Raske [6♀, EMEC: UCRCENT00404876, UCRCENT00404879– 83] GoogleMaps . Tamaulipas: Tampico , 22 ° 15’19”N, 97 ° 52’7”W, E. A. Shwarz [1♀, USNM: UCRCENT00416811] GoogleMaps . Veracruz: Coyame, Lake Catemaco, 336m, 18 ° 23’45”N, 95 ° 04’13”W, 14.vii.1971, Clark, Murray, Hart, Schaffner [2♀, TAMU: UCRCENT00243098, UCRCENT00243045]. Nogales, 18 ° 50’53”N, 97 ° 10’30”W, vii.1955, N.L.H. Kraus [1♀, BPBM: UCRCENT00422379]. Paso de San Juan , 19°12’8”N, 96°19’26”W, 24.iv.1953, R.C. Bechtel & E.I. Schlinger [1?, EMEC: UCRCENT00404884]. Additional material examined. EL SALVADOR GoogleMaps . Cuscutlan: Colima , 14 ° 03’36”N, 89 ° 08’04”W, 24.vi.1958, L.J. Bottimer [4♀, USNM: UCRCENT00248629–32] GoogleMaps . La Libertad: Quezaltpeque , 13 ° 49’53”N, 89 ° 16’49”W, 21.vi.1961, M.E. Irwin [1♀, UCDC: UCRCENT00243427]; 500m, 5.vii.1963, D.Q. Cavagnaro & M.E. Irwin [2♀, 1³, CAS: UCRCENT00417321, UCRCENT00417329–30]. GUATEMALA GoogleMaps . Jalapa: 3 km S. Jalapa , 1300m, 14 ° 36’00”N, 89 ° 58’48”W, 12–13.ix.1987, Sharkey [1♀, CNC: UCRCENT00505455]. HONDURAS GoogleMaps . Atlántida: Lancetilla, Tela , 15°43’00”N, 87°27’00”W, 31.viii.1995, R. Cave, MT [1♀ MZLU: UCRCENT00242600]. MEXICO GoogleMaps . Guerrero: 8 mi. S.E. Iguala , 18°15’55”N, 99°28’2”W, 22.viii.1958, H.F. Howden GoogleMaps [1♀, CNC: UCRCENT00415449]. 100 km S. Zihuataneijo, 17 ° 10’12”N, 100 ° 43’48”W, 6.viii.1984, G. Gordh GoogleMaps [2³, UCRC: UCRCENT00435201–02] GoogleMaps .

Etymology. From Greek poly meaning “many” and myrmex meaning “ant” in reference to the multiple host ant genera implicated for this species.

Discussion. There may be more cryptic species diversity within this taxon considering the range of host records. The males from Guerrero, Mexico (UCRCENT00435201–02) and El Salvador (UCRCENT00417321) have a significantly longer petiole (PTL:PTW = 2.6–2.7) than the males from Jalisco, Mexico (PTL:PTW = 0.8–1.2; UCRCENT00416799–800, UCRCENT00416804–07, UCRCENT00416809–10), which is a trait that tends not to vary this much in other species. Lacking molecular data for this clade, we feel that it is premature to recognize further species at this time.


USA, Massachusetts, Cambridge, Harvard University, Museum of Comparative Zoology


USA, Texas, College Station, Texas A & M University


USA, Idaho, Moscow, University of Idaho, W.F. Barr Entomological Collection


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


USA, California, Berkeley, University of California, Essig Museum of Entomology


USA, California, Riverside, University of California


Canada, Ontario, Ottawa, Canadian National Collection of Insects


Mus. Tinro, Vladyvostok