Orasema tolteca

Baker, Austin J. & Heraty, John M., 2020, The New World ant parasitoid genus Orasema (Hymenoptera: Eucharitidae), Zootaxa 4888 (1), pp. 1-84 : 36-38

Orasema tolteca species group

( Figs 17–20 )

Established by Heraty (2000).

Diagnosis. Recognized by the following combination of characters: generally large body size (among the largest of all Orasema ), anterior margin of fore wing costal cell with bare area ( Fig. 20H ), head with face flat and with relatively small eyes ( Figs 18B , 20B ), antenna with 8 funiculars in females ( Figs 18D , 20D ) and 9 funiculars in males ( Figs 18E , 20E ), mesoscutal midlobe not reticulate and sparsely setose ( Figs 18F , 20F ), petiole cylindrical, postmarginal vein at most slightly longer than stigmal vein, and mesosoma relatively high, broad, and short longitudinally.

Description. Female. Length 2.8–5.2 mm. Color. Flagellum dark brown. Mandible, maxilla, and labium brown. Coxae iridescent green; tibiae yellow. Fore wing hyaline, venation pale brown. Petiole same as mesosoma.

Head. Head in frontal view subtriangular to broadly triangular; face reticulate often with elongate reticulations between the eye and scrobe; scrobal depression shallow, laterally rounded, with transverse striae; longitudinal groove between eye and torulus absent; eyes sparsely setose; malar depression weakly impressed between mouth and eye margin; supraclypeal area longer than broad, weakly reticulate; clypeus weakly reticulate; epistomal sulcus vaguely defined; anterior tentorial pit strongly impressed; anteclypeus distinct, straight. Mandibular formula 3:2; palpal formula 3:3. Occiput imbricate, shallowly emarginate in dorsal view, dorsal margin evenly rounded; temples present, rounded. Scape reaching median ocellus. Pedicle small and globose. Flagellum with 8 funiculars; anellus disc-shaped; funiculars subequal in length distally, successively shorter; clava subovate. Mesosoma. Mesoscutal midlobe rugose-areolate to rugose reticulate, sparsely setose; lateral lobe costate dorsally, rugose laterally; notauli shallow. Axilla dorsally rounded, on roughly same plane as mesoscutellum; scutoscutellar sulcus broad, irregularly foveate, narrowly separated from transscutal articulation; mesoscutellar disc as long as broad, rugose; frenal line foveate; frenum areolate. Propodeal disc flat, without depression or carina; callus with a few small setae. Propleuron convex, strigate. Prepectus triangular dorsally, strongly narrowed ventrally. Mesepisternum reticulate laterally, areolate-reticulate anteriorly, broadly rounded anterior to mid coxa; postpectal carina prominent. Lower mesepimeron rugose-reticulate; transepimeral sulcus distinct. Metepisternum laterally rugose-reticulate. Hind coxa reticulate laterally, smooth ventrally; hind femur evenly covered with setae; hind tibia densely setose. Fore wing with basal area and speculum bare, costal cell mostly setose but with bare area near margin, wing disc densely setose; marginal fringe minute; submarginal vein with several long setae; marginal vein setose; stigma vein about as long as broad, slightly angled toward wing apex; postmarginal vein as long as stigma vein or slightly longer. Hind wing costal cell with broad, bare area. Metasoma. Petiole cylindrical, linear in profile, anterior carina strong, lateral margin with longitudinal carina continuous with basal flange. Antecostal sulcus foveate; acrosternite posteriorly rounded; apical setae of hypopygium with one pair of setae much longer than the others. Ovipositor with subapical carina present; first (ventral) valvula with 10 or 11 small, closely-spaced teeth.

Male. Length 3.5–4.6 mm. Scape dark brown with green iridescence; flagellum with 9 funiculars; anellus discshaped. Tibiae yellow.

Phylogenetics. Both species of this group, O. tolteca and O. castilloae , are represented in the analyses from Baker et al. (2020), which were referred to as “ Orasema _tolteca_ MEX _D4718” and “ Orasema _nr_tolteca_ USA: AZ_AE_D41 33”, respectively. These two species are sister groups in all analyses with AHE sequence data and were treated as part of the cockerelli species group despite O. tolteca being treated as its own group by Heraty (2000). In molecular analyses they rendered the remaining cockerelli group species paraphyletic by being more closely related to Nearctic cockerelli group than the Neotropical cockerelli group. We treat the tolteca group independently here, but to maintain a cladistic classification, we recognize and revise the heacoxi group and recognize the Neotropical vianai group for future revisionary work. The split between O. tolteca and O. castilloae is estimated to have occurred 5–15 MYA.

Key to species of the Orasema tolteca species group

1) Labrum with 4–6 digits; hind femur with dark iridescent patch from base along at least 3/4 of length ( Fig. 20A ); male FL:HH = 2.1–2.6 (central to southern Mexico)................................................... Orasema tolteca Mann

- Labrum always with 4 digits ( Fig. 18B ); hind femur light-colored near base and with dark iridescent patch along 2/3 length ( Fig. 18A ); male FL:HH = 1.8–2.0 ( Mexico: SO; United States: AZ)......................... Orasema castilloae n. sp.

Figures

FIGURE 17. Distribution map of species in the Orasema tolteca species group.

FIGURE 18. Orasema castilloae. Holotype female (UCRCENT00412574): A, habitus, lateral; B, head, anterior; C, mesosoma, lateral, arrow indicating presence of anterior prepectal carina; D, antenna; F, mesosoma, dorsal; G, propodeum, posterior. Paratype male (UCRCENT00416866): E, antenna.

FIGURE 19. Immature stages of Orasema tolteca. A, planidium head, ventral; B, planidium habitus (dorsal left and ventral right); C, planidium habitus, lateral. D, pupa habitus, dorsolateral. Modified from Heraty (1990).

FIGURE 20. Orasema tolteca. Syntype female (UCRCENT00318645): A, habitus, lateral; B, head, anterior; C, mesosoma, lateral; D, antenna; F, mesosoma, dorsal; G, propodeum, posterior. Male (UCRCENT00417437): E, antenna. Female (UCRCENT00478756): H, fore wing costal cell, arrow indicating bare anterior area.