Orasema nebula, 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 : 46-48

Orasema nebula n. sp.

urn:lsid:zoobank.org:act:F3D8994D-70D5-4C9F-8069-D2DB352BC0B1

( Fig. 23 )

Diagnosis. Distinguished from O. brachycephala by the flagellomeres being approximately as wide as long (cupshaped) with distinct peduncles ( Fig. 23A ), the petiole (female) that is longer than the hind coxae, the propodeum with a medial carina but without areolate sculpture ( Fig. 23G ), and a shorter body length. Distinguished from O. tinalandia by having more reticulate sculpture on the mesosoma ( Fig. 23F ) and having a petiole that is longer than the hind coxae.

This species is most similar to O. sixaolae but can be distinguished by a longer body (female ML:MH = 1.6 versus 1.1–1.4 in O. sixaolae ), smoother sculpture on the face ( Fig. 23A ), a generally smaller MSP:EYH that gives the head a more circular appearance ( Fig. 23A ), and a shorter/wider petiole in both sexes.

Female. Length 1.8 mm ( Fig. 23A ). Color. Head and mesosoma brownish black with some blue-green iridescence. Mandible brown. Femora mostly brown, tips pale; tibiae pale brown. Head ( Fig. 23B ). Head in frontal view subovoid; HW:HH = 1.3; face weakly reticulate, nearly smooth; longitudinal groove between eye and torulus present or absent; eyes sparsely setose, IOD:EH = 1.5; MS:EH = 0.6; malar depression weakly impressed adjacent to mouth; supraclypeal area slightly broader than long, smooth; clypeus smooth; epistomal sulcus distinct and sharply defined. Labrum with 4 digits. Mandibular formula not observed; palpal formula 3:2. Occiput with dorsal margin evenly rounded; temples absent. Pedicel globose, broader than F1. FL:HH = 1.5; anellus disc-shaped; F2L:F2W = 1.4, F2L:F3L = 1.2; following funiculars subequal in length, gradually broader; clava subovate ( Fig. 23D ). Mesosoma ( Fig. 23C, F ). ML:MH = 1.6. Mesoscutal midlobe imbricate to reticulate, sparsely setose; lateral lobe irregularly finely reticulate. Axilla weakly reticulate; scutoscutellar sulcus broad, irregularly foveate, broadly separated from transscutal articulation; mesoscutellar disc slightly longer than broad, irregularly finely reticulate; frenal line thin and irregularly foveate; axillular sulcus indicated by a weak longitudinal carina. Propodeal disc smooth laterally, with irregular median carina ( Fig. 23G ); callus with several short setae on dorsal margin. Propleuron smooth. Prepectus smooth to weakly reticulate. Mesepisternum reticulate laterally, smooth ventrally. HCL:HCW = 1.8; HFL: HFW = 5.7, setose dorsally and laterally. FWL:FWW = 2.3, FWL:ML = 2.3; basal area and speculum bare, costal cell and wing disc densely setose; submarginal vein with small setae; stigmal vein slightly angled toward wing apex; postmarginal vein slightly longer than stigmal vein. Hind wing costal cell entirely setose. Metasoma. PTL:PTW = 2.8, PTL:HCL = 1.2, areolate, lateral margin rounded, ventral sulcus absent. Antecostal sulcus smooth; acrosternite posteriorly angulate; apical setae of hypopygium with one pair of long setae. Ovipositor with subapical carina present; first (ventral) valvula with 6–8 small, narrowly separated teeth, second (dorsal) valvula with 8–10 annuli that are broadly separated dorsally by smooth area.

Male. Length 1.9 mm. HW:HH = 1.3. FL:HH = 1.6; F2L:F2W = 1.6 ( Fig. 23E ). Tibiae pale brown. PTL:PTW = 5.0, PTL:HCL = 2.4.

Hosts. Unknown.

Plant associates. Unknown.

Distribution ( Fig. 21 ). Ecuador: OR. Collected in February, October, and December.

Material examined. Holotype. ECUADOR. Orellana: Tiputini Biodiversity Station, nr Yasuni National Park , 220-250m, 03°7’55”S, 76°08’39”W, 8.ii.1999, T.L. Erwin et al., terre firme forest, Fogging, Lot # 2024 [♀, depos-ited in USNM: UCRCENT00247795] . Paratype. ECUADOR. Orellana: 1 km S. Onkone Gare Camp, Reserva Etnica Waorani , 216.3m, 03°9’25”S, 76°27’10”W, 8.x.1995, T.L. Erwin et al., terre firme forest, Fogging, Lot# 1259 [1³, USNM: UCRCENT00247799] .

Discussion. The collection events in Ecuador where specimens of O. nebula have been collected by canopy fogging also collected many more specimens of O. sixaolae , confirmed by molecular sequencing ( Baker et al. 2020). Most of these O. sixaolae specimens are distinct, but some closely resemble to O. nebula (e.g. UCRCENT00247800, UCRCENT00311894).

Etymology. From Latin nebula meaning “cloud or fog” in reference to specimens being collected from canopy fogging.

Figures

FIGURE 21. Distribution map of species in the Orasema sixaolae species group.

FIGURE 23. Orasema nebula. Holotype female (UCRCENT00247795): A, habitus, lateral; B, head, anterior; C, mesosoma, lateral; D, antenna; F, mesosoma, dorsal; G, propodeum, posterior. Paratype male (UCRCENT00247799): E, antenna.