Opius macrocornis Fischer

Taxonomic History / Nomenclature
Opius macrocornis Fischer, 1965: 298–300. Holotype male in AEIC (examined).
Opius macrocornis: Fischer 1965: : 419 (key); Fischer 1969: 162–163 (key); Fischer 1971: 84 (catalog).
Opius (Pendopius) macrocornis: Fischer 1977: 714–715, 727–728 (key, redescription); Fischer 1979: 484–486, 495 (key); Yu et al. 2005, 2012 (electronic catalogs).
This species is known only from the male holotype.
Diagnosis and Relationships
Face (Fig. 2) very faintly punctate, otherwise smooth, polished throughout. Eye in lateral view (Fig. 3) 2.4–2.6 x longer than temple; temples in dorsal view not or only weakly receding (Fig. 4). Male antenna with 45 flagellomeres; setae on basal flagellomeres thick, dark. Mesoscutum with weak declivity (Fig. 5); supramarginal carina absent or apparently so. Propodeum (Fig. 6) smooth, polished with shallow median trough anteriorly continuous with broader, weakly defined areola posteriorly. Fore wing 3RSa straight, about 1.6 x longer than 2RS; m-cu postfurcal. T1 evenly curving into basal pit anteriorly (Fig. 7), not distinctly declivitous, pit well-defined, delimited posterior-medially; surface smooth, polished; dorsal carinae (Fig. 8) parallel-sided for most of their length, distinctly converging near posterior margin, not sinuate, not transversely carinate between dorsal carinae. T2+T3 smooth, polished. Color as in Fig. 1: head, body, hind coxa and femur pale orange; antenna without pale subapical ring; wing darkly infumate.

This species is very similar to O. nimifactus , as noted by Fischer (1979). Both species are characterized by greatly reduced propodeal sculpture (Figs 6, 10), relatively smooth T1, and absence of any shagreening on T2. T1 anteriorly is more gradually sloping in O. macrocornis, and O. macrocornis is more uniformly pale orange: lacking the black tegula and dark margins of the mesoscutum that characterize O. nimifactus (Fig. 11). There is a patch of sculpture between the notaulus and the anterior-lateral margin of the mesoscutum in O. nimifactus but this area is largely smooth in O. macrocornis. The mesoscutum is also weakly declivitous in O. macrocornis but flatter in O. nimifactus. Fischer (1979) provides additional comparison of the two species.

Both of these species were placed in the subgenus Pendopius by Fischer (1977, 1979) because of the absence of sculpture on T2. The shagreened sculpture on the metasoma appears to vary intraspecifically in opiines when there is sufficient material for comparison, and is often extremely weak in some of the species of the ingenticornis species group. We therefore do not consider the sculpture pattern alone to be adequate for characterizing subgenera or species groups, and treat it as variably present or absent in the ingenticornis species group. Both O. macrocornis and O. nimifactus fall within our concept of the ingenticornis species group, resembling species with relatively reduced sculpture and darker, thicker flagellar setae such as O. curiosicornis .

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. macrocornis holotype habitus...
2.O. macrocornis holotype face
3. O. macrocornis holotype head late...
4. O. macrocornis holotype head dors...
5. O. macrocornis holotype mesosoma ...
6. O. macrocornis holotype propodeum...
7. O. macrocornis holotype T1 latera...
8. O. macrocornis holotype T1 dorsal...
9. O. macrocornis holotype fore wing...
10.O. nimifactus propodeum
11.O. nimifactus dorsal habitus
Peru, Quincemil, near Marcapata
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 1-3.
1.Holotype data label
2.Holotype label
3.Institutional 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) 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.