Opius antennatus Fischer

Taxonomic History / Nomenclature
Opius antennatus Fischer, 1965: 65–67. Holotype female in AEIC (examined).
Opius antennatus: Fischer 1971: 43 (catalog).
Opius (Merotrachys) antennatus: Fischer 1977: 655–659 (key, redescription); Fischer 1979: 264–266 (key); Yu et al. 2005, 2012 (electronic catalogs).
As of 2013, known only from holotype and one paratype, both males.
Diagnosis and Relationships
Face (Fig. 3) faintly punctate, nearly smooth except shagreened adjacent eye margin. Eye in lateral view (Fig. 4) 2.5–3.0 x longer than temple; temples in dorsal view weakly receding (Fig. 5). Male antenna with 48 flagellomeres; setae on basal flagellomeres thin, pale. Mesoscutum anteriorly (Fig. 4) with shallow but distinct declivity; notaulus extending laterally towards tegula as groove bordered by distinct supramarginal carina (Fig. 4). Propodeum rugose to rugulose, median areola absent, median trough anteriorly shallow. Fore wing (Fig. 9) with 3RSa very weakly curved, 1.35–1.4 x longer than 2RS; m-cu very weakly postfurcal. T1 sharply declivitous anteriorly (Fig. 7), basal pit delimited posterior-medially; surface smooth to rugulose; dorsal carinae parallel-sided throughout, not sinuate (Fig. 8), very weakly transversely carinate between dorsal carinae. T2+3 uniformly, distinctly shagreened (Fig. 8). Color as in Figs 1, 2, 5, 6, 8: head and mesosoma largely pale orange, mostly brownish orange dorsally; T1 orange, T2–4 pale medially, dark brown laterally, T5–6 dark brown; hind coxa and femur whitish; antenna without subapical pale ring; wing hyaline.

Opius antennatus is the smallest of the species presently included in the Opius ingenticornis species group, with body length about 2.1 mm. The color pattern is distinctive, dorsally infumate on the head and mesosoma, yellow-orange below (Figs 2, 5, 6). Opius antennatus is closest to O. michaeli in color pattern, though O. michaeli has a dark mesopleuron and somewhat darker legs. The mesoscutum has a weak anterior declivity in both, but T2+3 is more distinctly shagreened in O. antennatus than in O. michaeli.

Additionally, as in all other members of the ingenticornis species group, this species can be further characterized as follows: Mandible short, broadly triangular, dorsal margin strongly angled ventrally, broadly exposing labrum. Clypeus shaped as a broad crescent, nearly hemispherical, flat to weakly protruding ventrally, ventral margin shallowly concave, rarely appearing truncate. Malar sulcus distinct, complete. Antenna unusually long, approximately twice longer than body; first flagellomere slender, longer than second, with long, narrow plate sensilla. Occipital carina broadly absent dorsally, the gap in dorsal view at least as wide as distance between eyes; carina well developed laterally and ventrally, widely separated from hypostomal carina ventrally. Pronope deep, wide, posterior margin at least weakly overlapping base of mesoscutum, thus obliterating posterior transverse sulcus medially; vertical carina absent on pronotum laterally. Mesoscutum without midpit; notaulus short, curved, pit-like anteriorly, narrowing and evanescent posteriorly. Propodeum with median depression at least anteriorly, never with median longitudinal carina. Mesopleuron without sternaulus, precoxal sulcus unsculptured, absent or very faintly indicated; hind margin of mesopleuron not obviously crenulate on dorsal 0.5. Fore wing 2CUb arising from or near middle of first subdiscal cell. Hind wing with RS distinctly infumate; m-cu absent. T1 with dorsal carinae parallel or nearly so, extending from base to apex; laterope large, deep; dorsope absent.

1.O. antennatus holotype habitus
2. O. antennatus holotype lateral vi...
3.O. antennatus holotype face
4. O. antennatus holotype head later...
5. O. antennatus holotype head dorsa...
6. O. antennatus holotype mesosoma d...
7. O. antennatus holotype T1 lateral...
8. O. antennatus holotype T1 dorsal...
9. O. antennatus holotype fore wing...
This species, described from South Carolina, USA, has the northernmost distribution of species belonging to the ingenticornis species group, and is the only species of this species group thus far recorded from outside of the Neotropical Region.
No referenced distribution records have been added to the database for this OTU.

There are no specimens currently determined for this OTU, or those specimens determined for this OTU are not yet mappable.

Label data
Labels attached to the holotype are shown in Figs 1 and 2. Holotype. The third label on the pin indicates a separate preparation (for the left wings). The fifth label on the pin is a yellow institutional label: Type No. 417

Paratype. One male, USA, South Carolina, Greenville, 12.vii.1952, G. & L. Townes.

1.Holotype labels
2.Holotype label
This page was assembled largely by Bob Wharton. It is part of a revision of the Opius ingenticornis species group conducted by Sophia Daniels, Xanthe Shirley, Danielle Restuccia and Bob Wharton, published by Wharton et al. (2013). We thank David Wahl (American Entomological Institute, Gainesville, FL) and Norm Penny and Bob Zuparko (CAS) for loans and general assistance associated with examination of holotypes, as well as Max Fischer and Dominique Zimmermann (NHMW), Henri Goulet (CNC) and Paul Marsh (formerly USDA, Washington, D. C.) for facilitating other loans and work with material in their care. We are also sincerely grateful to Jim Woolley and Aaron Tarone for making available their imaging systems when ours crashed. Matt Yoder provided guidance on databasing issues associated with our use of mx. This work was conducted at Texas A&M University and was supported in part by NSF DEB 0949027, with REU supplement 1213790. Page last updated May, 2013.

This material is based upon work supported by the National Science Foundation under Grant Number DEB 0949027 and associated REU supplement 1213790.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.