The Wharton Lab

Xiomara Gauld, 1997. Type species Xiomara grilloi Gauld, 1997. Monobasic and original designation.

There is only one described species as of 2010:
Xiomara grilloi Gauld, 1997

The type species was based on a single male specimen from Costa Rica (Gauld 1997). I have not seen the holotype; the above description is based on three females from Costa Rica, Mexico, and French Guiana.

Xiomara is defined largely by the pattern of reduction of the occipital carina and the propodeal carinae, and by the very short but strongly impressed notaulus. Xiomara belongs to the group of perilissine genera with a smaller, more basally displaced glymma with the dorsal tendon attachment within a distinct basal median pit. Gauld, 1997 included the north temperate Lathiponus, Synoecetes, and Zaplethocornia in this group as well as the neotropical genera Coelorhachis, Tetrambon, Sialocara, Jorgeus, and Peakelestes. See the Coelorhachis, Jorgeus, and Sialocara pages for additional discussion. Xiomara is most similar to Sialocara based on reductions of the occipital carina in both genera and these two share other features of the wing venation, clypeus, and T1 suggestive of a close relationship with Coelorachis and Jorgeus.

Clypeus with ventral margin thick and usually bluntly rounded, margin somewhat rugose in at least one species; ventral margin usually weakly indented medially; epistomal sulcus present, distinctly impressed laterally, weaker but still distinct mid-dorsally, clypeus protruding ventrally in profile. Malar space distinct but short, less than half basal width of mandible. Mandible with ventral tooth distinctly longer than dorsal tooth. Ocelli small, lateral ocellus much shorter than distance between ocellus and eye. Maxillary palp about as long as head height; female antennae about equal in length to body; first flagellomere with discrete tyloid containing fewer than 15 sensilla. Occipital carina absent mid-dorsally, present dorsal-laterally (Fig. 2), absent ventrally; hypostomal carina therefore not meeting occipital carina. Dorsal end of epicnemial carina widely separated from anterior margin of mesopleuron. Notaulus (Figs 3, 4) sharply impressed basally but short, barely extending to level of tegula and absent posteriorly. No distinct u- or v-shaped groove or notch, but shallow impression present between propodeum and metanotum in lateral view; pleural carina complete, well-developed; propodeal carinae nearly absent, with distinct apical spurs representing longitudinal carinae and sometimes weak traces of posterior transverse carinae laterally. Apical margin of mid tibia not 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 widely spaced, not dense as in typical comb; posterior hind tibial spur at least 7x longer than maximum width at base; tarsal claws pectinate, though teeth usually weaker apically. Fore wing (Fig. 5) with areolet present; Rs+2r arising at or near midpoint of stigma. Hind wing with first abscissa of CU1 slightly longer than 1cu-a (Fig. 6). T1 (Figs 7, 8) not long and slender, gradually broadening posteriorly, without dorsal carinae; basal depression at dorsal tendon attachment deep, distinct, extending posteriorly for short distance as posteriorly narrowing, shallow groove; dorsal-lateral carina extending from spiracle to apex of T1 absent or nearly so, with trace of carina posteriorly in some specimens; glymma (Fig. 8) deep, somewhat rounded, basally displaced, extending into median basal depression, the two glymmae not meeting on each side posterior to basal depression. T2 thyridium absent; laterotergites on T2 and especially T3 not distinctly separated by creases on specimens available for examination. Ovipositor straight, with very shallow, broad subapical notch; ovipositor sheath shorter than half length of hind basitarsus, very weakly expanding distally, somewhat rounded distally. Male parameres apically produced into a rounded point.

Xiomara was described from a single specimen collected in Costa Rica. I have seen an additional specimen of the type species, determined by Gauld, also from Costa Rica (American Entomological Institute), as well as a single specimen each of two different undescribed species from Mexico (Texas A&M collection) and French Guiana (Canadian National Collection).

The biology is 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 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, Amanda Ladigo, Heather Cummins, and Cheryl Hyde graciously assisted with image capture, processing, and formatting. 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.