Orasema heacoxi, 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 : 65-67

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Orasema heacoxi


Orasema heacoxi species group

( Figs 35–37 View FIGURE 35 View FIGURE 36 View FIGURE 37 )

Diagnosis. Recognized by the following combination of characters: flagellum with 7 funiculars ( Figs 36D, E View FIGURE 36 , 37D, E View FIGURE 37 ), fore wing with basal third bare, face reticulate ( Figs 36B View FIGURE 36 , 37B View FIGURE 37 ), postpectal carina absent ( Figs 36C View FIGURE 36 , 37C View FIGURE 37 ), propodeum areolate-reticulate ( Figs 36G View FIGURE 36 , 37G View FIGURE 37 ), and petiole rugose-reticulate.

This group is most similar to the cockerelli and bakeri species groups. It can be distinguished from the cockerelli group by having the mesoscutal midlobe rugose-reticulate or, if reticulate, having an elongate face and the frenum semicircular when viewed dorsally. It is distinguished from the bakeri group by the prepectus having a distinct anterior carina.

Description. Female. Length 1.7–2.2 mm. Color. Head and mesosoma iridescent blue-green. Pedicel and anellus brown; flagellum dark brown. Maxilla and labium brown. Coxae brown with strong blue-green iridescence; tibiae yellow. Wing venation pale brown. Head. Face reticulate; scrobal depression shallow, laterally rounded, with transverse striae; eyes bare; supraclypeal area longer than broad, weakly reticulate; clypeus weakly reticulate; anterior tentorial pit strongly impressed; anteclypeus distinct, broadly rounded. Labrum with 4 digits. Mandibular formula 3:2, palpal formula 3:2. Occiput imbricate-reticulate, dorsal margin evenly rounded; temples present, rounded. Scape not reaching median ocellus. Flagellum with 7 funiculars; anellus disc-shaped; following funiculars subequal in length, gradually broader; clava subconical. Mesosoma. Mesoscutal midlobe sparsely setose; lateral lobe reticulate; notauli deep. Axilla reticulate, dorsally rounded, on roughly the same plane as mesoscutellum; scutoscutellar sulcus regularly foveate; mesoscutellar disc slightly longer than broad, reticulate; frenal line indistinct; axillular sulcus weak and foveate. Propodeal disc broadly rounded, without depression or carina, areolate-reticulate; callus weakly reticulate, bare; callar nib absent. Propleuron convex, reticulate. Prepectus weakly reticulate. Mesepisternum straight anterior to mid coxa; postpectal carina absent. Hind femur sparsely setose. Fore wing with basal third bare, costal cell sparsely setose, wing disc setose; marginal fringe relatively long; submarginal vein with small setae; marginal vein pilose; stigmal vein slightly longer than broad, slightly angled toward wing apex; postmarginal vein shorter than stigmal vein. Hind wing costal cell with a broad bare area. Metasoma. Petiole cylindrical, linear in profile, rugose-reticulate. Antecostal sulcus foveate; acrosternite posteriorly rounded. Ovipositor with subapical carina present; first (ventral) valvula with 10 or 11 small, closely spaced teeth, second (dorsal) valvula with 8–10 annuli that are broadly separated dorsally by smooth area.

Male. Length 1.8–2.1 mm. Flagellum with 7 funiculars; anellus disc-shaped. Femora mostly brown with iridescence, tips pale.

Phylogenetics. Both species included in the group are represented in the phylogenetic analyses of Baker et al. (2020), which referred to O. heacoxi as “ Orasema _nsp_ USA:TX_D4107 and O. masonicki as “ Orasema _sp_CRI_ D4887. The two species are sister species in every analysis except the analyses only using Sanger sequencing data, which resulted in a very poorly resolved cockerelli group (parsimony) or split O. masonicki away from the cockerelli group (ML and BEAST). In analyses with AHE sequencing data, the sister relationship is supported with 99 or 100 bootstrap scores. This group was treated as part of a more inclusive cockerelli group by Baker et al. (2020), but we split it into its own group because the two species are fairly distinct compared to other Nearctic cockerelli group species, which themselves form a well-supported clade. The split between O. heacoxi and O. masonicki is estimated to have occurred 5–17 MYA; the split between the heacoxi group and cockerelli group is estimated to have occurred 10–20 MYA.

Key to species of the Orasema heacoxi species group

1) Face subtriangular to subcircular ( Fig. 36B View FIGURE 36 ); mesoscutal midlobe, axilla, and mesoscutellar disc rugose-reticulate ( Fig. 36F View FIGURE 36 ); petiole relatively short (PTL:PTW = 1.0–2.1 female; 3.8–5.5 male); male antennal flagellomeres pedunculate with semi-erect, curved setae ( Fig. 36E View FIGURE 36 ) (Texas)........................................................ Orasema heacoxi n. sp.

- Face elongate ( Fig. 37B View FIGURE 37 ); mesoscutal midlobe, axilla, and mesoscutellar disc reticulate ( Fig. 37F View FIGURE 37 ); petiole relatively long (PTL: PTW = 2.5–3.4 female; 5.5–7.5 male); male antennal flagellomeres closely spaced with straight, closely-appressed setae ( Fig. 37E View FIGURE 37 ) ( Costa Rica)................................................................. Orasema masonicki n. sp.