The Wharton Lab

Tetrambon Townes, 1970. Type species: Tetrambon fuscipes Townes, 1970. Original designation.

Townes, 1970 included three species in his original description of the genus, and no others have been described as of 2010.

Tetrambon fuscipes Townes, 1970
Tetrambon pallipes Townes, 1970
Tetrambon platyura Townes, 1970

Defined largely by the long ovipositor, an usual though not unique feature among perilissines, and the short, broad stigma of the fore wing. Tetrambon belongs to the group of perilissine genera characterized by Gauld (1997) on the basis of the basal glymma (the Coelorhachis group: see the Coelorhachis page). Within that group, Tetrambon most closely resembles Peakelestes on the basis of the long ovipositor. Tetrambon lacks the other unusual features that characterize Peakelestes. Resemblance between the two is likely due to convergence, but the relationships would be worth further exploration.

Clypeus variable among species and sexually dimorphic in at least one species; ventral margin thick and bluntly rounded in male of T. pallipes and in both sexes of at least one other species, thin and sharp in female of T. pallipes (Fig. 2); ventral margin varying from concave (in T. platyura) through arcuate medially, sharply angled laterally (in female of T. pallipes, Fig. 2) to weakly convex throughout in males and some females; strongly protruding ventrally in profile; epistomal sulcus distinctly impressed throughout. Malar space very short, nearly absent. Mandible with ventral tooth very distinctly longer than dorsal tooth. Ocelli small, lateral ocellus much shorter than distance between ocellus and eye. Maxillary palp equal to or slightly shorter than height of head; female antennae about equal in length to body; tyloid not readily visible on most specimens available for study, presence needs confirmation. Hypostomal carina joining occipital carina well above base of mandible; occipital carina complete. Dorsal end of epicnemial carina extending to anterior margin of mesopleuron. Notaulus varying from sharply to weakly impressed basally, usually confined to anterior declivity, rarely extending posteriorly to level of tegula as a weak crease. No distinct u- or v-shaped groove or notch: small, broad, shallow groove present between propodeum and metanotum in lateral view; pleural carina complete, well-developed; propodeal carinae (Fig. 4) mostly well-developed, but varying interspecifically, anterior transverse carinae absent laterally, large areola narrowing anteriorly. Apical margin of mid tibia distinctly expanded into a distinct tooth similar to that on fore tibia; apical comb on hind tibia not well developed, row of setae present but these somewhat widely spaced, not as dense as in typical comb; posterior hind tibial spur about 7x longer than maximum width at base; tarsal claws completely pectinate, but with apical pectin so large that claws often appear cleft. Fore wing areolet usually present (absent or poorly developed in about 15% of specimens examined); stigma very short and broad, Rs+2r arising at or near midpoint. Hind wing with first abscissa of CU1 distinctly longer than 1cu-a. T1 (Fig. 5) moderately short and broad, distinctly broadening posteriorly, with sharp dorsal carinae basally, extending to or nearly to level of spiracles; basal depression at dorsal tendon attachment small but distinct; sharp dorsal-lateral carina extending from spiracle to apex of T1; glymma basally displaced, extending into median basal depression, the two glymmae not meeting on each side posterior to basal depression. T2 thyridium absent; laterotergites of T2 completely separated by creases, those of T3 mostly so. Ovipositor varying from straight or nearly so to weakly upcurved, very long (Fig. 6 with ovipositor slightly twisted postmortem), much longer than hind tarsi; with dorsal, subapical notch distally varying from deep and narrow to shallow and barely discernible; ovipositor sheath long, narrow, slender, somewhat pointed distally. Male parameres somewhat broadly rectangular in dorsal view, never narrowly attenuate distally; aedeagus rounded and weakly clubbed distally.

Known only from southern South America; described from southern Chile (Concepcion south through Magallanes Provinces) and southern Argentina (Santa Cruz Province).

Biology completely unknown.

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, to Gavin Broad for exchange of information on Perilissini and especially to John Heraty for collecting fresh specimens from Chile. 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, Amanda Ladigo, Heather Cummins, and Cheryl Hyde 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 June, 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.