Orasema sixaolae

Baker, Austin J. & Heraty, John M., 2020, The New World ant parasitoid genus Orasema (Hymenoptera: Eucharitidae), Zootaxa 4888 (1), pp. 1-84 : 43

publication ID	https://doi.org/ 10.11646/zootaxa.4888.1.1
publication LSID	lsid:zoobank.org:pub:574A35A5-A551-4A7E-B2BC-481D703B1BE7
DOI	https://doi.org/10.5281/zenodo.4337783
persistent identifier	https://treatment.plazi.org/id/447187B9-FFB6-E56D-AAD1-FE6CAFA9F88A
treatment provided by	Plazi
scientific name	Orasema sixaolae
status

Treatment

Orasema sixaolae View in CoL species group

( Figs 21–25 View FIGURE 21 View FIGURE 22 View FIGURE 23 View FIGURE 24 View FIGURE 25 )

Diagnosis. Recognized by the following combination of characters: small-bodied (1.4–2.2 mm), antenna with 7 funiculars in both sexes, funiculars often wide and cup-shaped with a short peduncle, PTL:PTW = 1.6–4.2 (female), 5.0–7.8 (male). Generally, this group has a subcircular head shape, weak reticulate sculpture on the face and mesosoma, and dark body color.

Description. Female. Length 1.4–2.2 mm. Color. Scape, pedicel and anellus pale brown; flagellum brown. Maxilla and labium pale brown. Coxae brown. Wing venation pale brown. Gaster brown. Head. Scrobal depression shallow, laterally rounded, with transverse striae; anterior tentorial pit strongly impressed; anteclypeus distinct, broadly rounded. Occiput imbricate, emarginate in dorsal view. Scape not reaching median ocellus. Flagellum with 7 funiculars. Mesosoma. Notauli deep. Axilla dorsally rounded, on roughly the same plane as mesoscutellum; frenum and axillula smooth. Propodeal disc broadly rounded; callus smooth. Mesepisternum broadly rounded anterior to mid coxa. Upper and lower mesepimeron smooth; transepimeral sulcus distinct. Metepisternum laterally smooth. Propleuron convex. Postpectal carina weak. Hind coxa weakly reticulate. Fore wing marginal fringe relatively long; marginal vein pilose; stigmal vein slightly longer than broad. Metasoma. Petiole cylindrical, linear in profile.

Male. Length 1.5–2.0 mm. Scape pale brown; flagellum with 7 funiculars; anellus disc-shaped. Femora mostly brown, tips pale.

Phylogenetics. Orasema sixaolae and O. nebula , referred to as “nr. sixaolae” by Baker et al. 2020, are the only species molecularly sampled. Specimens of O. sixaolae sampled from Mexico, Costa Rica, Venezuela, and Ecuador are monophyletic with a crown age at about 4–7 MY and an average of 9.3% sequence variation between AHE-sequenced specimens, and O. nebula from Ecuador is the sister species. This species group is sister to O. monstrosa , which seems to share very few morphological similarities with the sixaolae group, warranting placement as its own group.

Key to species of the Orasema sixaolae View in CoL species group

1) Curvature of eyes in frontal view appearing continuous with the curvature of head ( Figs 24B View FIGURE 24 , 25B View FIGURE 25 ); female IOD:EYH>1.5; angle created by mesoscutellum, frenum, and propodeum less obtuse, closer to right angle, in lateral view ( Figs 24C View FIGURE 24 , 25C View FIGURE 25 ).. ................................................................................................... 2

- Curvature of eyes in frontal view discontinuous with curvature of head, eyes appearing to bulge from sides of head ( Figs 22B View FIGURE 22 , 23B View FIGURE 23 ); female IOD:EYH <1.5; angle created by mesoscutellum, frenum, and propodeum more obtuse in lateral view ( Figs 22C View FIGURE 22 , 23C View FIGURE 23 )............................................................................................... 3

2) Face and mesoscutal midlobe distinctly reticulate ( Fig. 24B, F View FIGURE 24 ); frenum in dorsal view <1/4 length of mesoscutellum ( Fig. 24F View FIGURE 24 ); female petiole longer/thinner (PTL:PTW = 3.1–4.1) (widespread Neotropical)....... Orasema sixaolae Wheeler & Wheeler View in CoL

- Face smooth ( Fig. 25B View FIGURE 25 ) and mesoscutal midlobe imbricate anteriorly but transitioning to smooth dorsally ( Fig. 25E View FIGURE 25 ); frenum in dorsal view>1/4 length of mesoscutellum ( Fig. 25E View FIGURE 25 ); female petiole shorter/wider (PTL:PTW = 2.2) ( Ecuador).......................................................................................... Orasema tinalandia n. sp.

3) Flagellomeres 3–8 as wide as long ( Fig. 23D, E View FIGURE 23 ); female petiole longer than hind coxa ( Costa Rica and Ecuador)............................................................................................ Orasema nebula n. sp.

- Flagellomeres all longer than wide ( Fig. 22D View FIGURE 22 ); female petiole subequal in length to hind coxa ( Brazil).............................................................................................. Orasema brachycephala n. sp.