The Wharton Lab

Oetophorus Foerster, 1869: 196. Type species: Mesoleius stretchii Cresson, 1879. Subsequent designation by Viereck (1914).

Symphobus Foerster, 1869: 199. Type species: Tryphon pleuralis Cresson, 1864. Subsequent inclusion by Davis (1897): 323 (monobasic). Synonymized by Townes (1939).

The four Nearctic species were revised by Barron (1997), who recorded extensive color variation for the type species, treated all previously described Nearctic species as synonyms of O. pleuralis, described three new species, and provided a useful summary of previous literature. The Palaearctic species were also revised by Barron (1998), who recognized a single species from Europe. He also described one new species each from Japan, Korea, and Taiwan, bringing the total number of valid species to 8.

The work by Davis bears the publication date of 1897 and is often cited as such. Perkins (1962) indicates that the second part of this publication, including the nomenclatural work cited above was published in 1898.

Oetophorus is distinguished from other perilissines, and most notably Perilissus, by the presence of a stout, ventral, spine-like seta near the inner, apical margin on the male paramere (Fig. 1). Additionally, the apex of the aedeagus is in the shape of an oblique, flat disc. Females are more challenging to recognize but can be separated from Perilissus by the presence of thin, lateral lobes along the ventral margin of the clypeus. Most Oetophorus can be separated from most Trematopygodes by the better developed propodeal carination and shorter first abscissa of CU1 in Oetophorus.

Prior to the work of Barron (1997, 1998), Oetophorus was generally placed near Perilissus and readily separated from Trematopygodes on the basis of hind wing venation. Species of Oetophorus described by Barron (especially Barron 1997) narrow the gap between Oetophorus and Trematopygodes and I regard the two as sister-groups primarily on the basis of the clypeal morphology and the shape and sculpture of T1.

Clypeus with ventral margin thick and bluntly rounded, with small, thin, rounded tooth laterally in female, this absent in male (Fig. 4); ventral margin convex; epistomal sulcus distinctly impressed throughout, clypeus weakly protruding in profile. Malar space distinct, relatively short, at most half basal width of mandible. Mandible with ventral tooth usually slightly but distinctly longer than dorsal tooth, much longer in O. maculatus. Ocelli small, lateral ocellus much shorter than distance between ocellus and eye. Maxillary palp about equal to or slightly shorter than head height; female antenna usually a little longer than body; first flagellomere with discrete tyloid containing fewer than 15 sensilla. Hypostomal carina joining occipital carina well above base of mandible; occipital carina complete. Dorsal end of epicnemial carina distant from anterior margin of mesopleuron. Notaulus varying from barely discernible (nearly absent) to short but distinctly impressed, confined to anterior declivity, not extending posterior to level of tegula. Small v-shaped notch absent or nearly so between propodeum and metanotum in lateral view, barely visible when rotated in oblique angle, distinct u-shaped notch not present; pleural carina complete, well-developed; propodeal carinae usually well-developed (Fig. 6), complete, areola hexagonal, usually relatively narrow, anterior transverse carina absent in O. obscurus. Apical margin of mid tibia rounded, not expanded into a distinct tooth similar to that on fore tibia; apical comb on hind tibia not well developed; posterior hind tibial spur at least 7x longer than maximum width at base; tarsal claws completely pectinate. Fore wing (Fig. 5) with areolet present; stigma relatively broad, Rs+2r arising at or near midpoint. Hind wing with first abscissa of CU1 variable: often distinctly shorter than 1cu-a, commonly only slightly shorter than 1cu-a, more rarely longer than 1cu-a. T1 (Figs 3, 6) not long and slender, gradually widening posteriorly, dorsal carinae barely indicated basally, absent posteriorly, but with weak median impression in type species; without basal depression at dorsal tendon attachment; dorsal-lateral carina usually sharp and distinct from spiracle to apex of T1; glymmae on each side meeting on the midline posterior to dorsal tendon attachment, deep, separated at midline by translucent partition. T2 thyridium absent; laterotergites of T2 and T3 completely separated by creases. Ovipositor (Figs. 1, 9) straight, relatively broad at base, with broad subapical notch terminating more abruptly distally than basally; ovipositor sheath long, nearly as long as hind basitarsus, parallel-sided, distal margin forming a sharp spine. Male parameres (Figs. 7, 8) broad, somewhat rectangular in dorsal view, broadly rounded, not attenuate distally, each paramere with a single, large, stout, spine-like seta ventrally; aedeagus adze-shaped.

Holarctic, with species from all across USA and Canada in the Nearctic; one species in the western Palaearctic, and one species each in Japan, Korea, and Taiwan as of 2005.

Hosts are known for two of the species, the Nearctic O. pleuralis and the western Palaearctic O. naevius. Barron (1997, 1998) provides lists of hosts and associated references. Both species are recorded from various species in the tenthredinid genera Nematus and Pristiphora. Barron (1997) also lists one species of Arge and one of Amauronematus for O. pleuralis.

This page was assembled by Bob Wharton as part of a larger collaborative effort on the genera of Ctenopelmatinae. This work would not have been possible without the groundwork provided by Ian Gauld’s study of the Australian and Costa Rican faunas, and we are particularly grateful for his assistance in many aspects of this study. We also thank David Wahl for useful feedback throughout our study and to Gavin Broad for exchange of information on Perilissini. Matt Yoder provided considerable assistance with databasing issues, and our use of PURLs (http://purl.oclc.org) in this regard follows the example of their use in publications by Norm Johnson. Andrea Walker, Cheryl Hyde, and Heather Cummins graciously assisted with image capture, processing, formatting, and literature retrieval. This study was supported by the National Science Foundation’s PEET program under Grant No. DEB 0328922 and associated REU supplement nos DEB 0723663 and 1026618. Page last updated March, 2011.

This material is based upon work supported by the National Science Foundation under Grant Number DEB 0328922 with REU supplements DEB 0723663 and number 1026618.
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.