The Wharton Lab

Physotarsus concavus Zhaurova, 2009: 9-10, 17-19. Holotype female in AEIC.

This species is somewhat color variable, this being perhaps more obvious relative to other species due to the large number of specimens available. The metapleuron, for example, varies from nearly all yellow to all black, and the extent of yellow markings on the mesoscutum is also quite variable. In addition to variation in leg coloration noted in the original description (Zhaurova and Wharton 2009), a few specimens from Arizona (not included as paratypes) have the hind tarsi entirely pale. The color variation makes it a challenge to differentiate several similarly colored species from southwestern U. S.

Lateral ocelli separated by 1.1-1.2X their widest diameter from each other and about 1.8-2.0X their widest diameter from eye margin. Antennae with 33-42 flagellomeres. Pronotum completely glabrous. Mesoscutum shiny, very sparsely punctate on anterior 0.3. T1 about twice as long as broad. Head yellow with broad, black median stripe extending from base of antenna through vertex; occiput almost completely black. Mesosoma black and yellow (Fig. 4). T1 yellow basally with two black bands extending from spiracle to or nearly to apex; T2 and often T3 with yellow triangular patch medially (Fig. 8), otherwise dark brown to black, remaining tergites largely dark laterally, variously yellow to orange medially. Hind femur and tibia orange, tarsomeres 1 and 2 brown, tarsomeres 3 and 4 usually yellow, sometimes only ventrally. Fore wing entirely hyaline.

Physotarsus concavus is one of several species with a black and yellow mesosoma, a distinctly punctate mesopleuron, and a sparsely to impunctate mesoscutum. It is nearly identical to P. cordatus, P. emarginatus, and P. truncatus, but differs from these in the possession of distinctly pale middle tarsomeres on the hind leg. The subapical ring on the flagellum is also more distinct in P. concavus.

Physotarsus concavus is very similar in color to P. emarginatus, and to a lesser extent P. cordatus. The hind tarsi are darker in P. emarginatus and the dorsoposterior corner of the mesopleuron is black, while in P. cordatus the hind legs and metasoma are more extensively orange. Physotarsus concavus differs from both of these species in the more shallowly concave male subgenital plate (Fig. 9).

Known only from southwestern USA (Arizona) and northern Mexico.

Hosts unknown.

Material Examined. Holotype female (AEIC, Type No. 3849): [USA, Arizona] first line of data label: “Portal, Ariz.” second line: “IX.3.1974” third line: “H.&M. Townes”. Paratypes: 2 females, 1 male, same data as holotype (AEIC); 19 females, 10 males, same data as holotype except dates ranging 13.viii–7.ix.1974, 23.viii1987 & 18.ix.1987 (AEIC, TAMU); Arizona, 4 females, 4 males, Parker Canyon Lk., 22–24.viii.1974 (H&M Townes) (AEIC, TAMU), 1 male, Nogales, 22.viii.1974 (H&M Townes) (AEIC); 1 male, MEXICO, Nuevo Leon, San Pedro Iturbide, 32 km W. Linares, 6.×.1962 (H&M Townes) (AEIC).

This page was assembled by Bob Wharton and Kira Zhaurova, and is part of a revision of the genus Physotarsus (Zhaurova and Wharton 2009). Material examined for this revision was borrowed from the Academy of Natural Sciences, Philadelphia, the American Entomological Institute, Gainesville (AEIC), The Natural History Museum, London, the U. S. National Museum of Natural History, Washington, D. C., and INBio, Costa Rica. We are particularly grateful to David Wahl for the extended loan of the specimens listed above, as well as to Matt Yoder for the electronic interface and to Heather Cummins and Mika Cameron for assistance with literature and figures. We would also like to acknowledge the kind assistance of Ian Gauld, David Wahl, Andrew Bennett, and Gavin Broad for information exchange about ichneumonids during the course of this work. Our use of PURLs (http://purl.oclc.org) for the web interface follows the example of their use in publications by Norm Johnson. The work was conducted at Texas A&M University and supported by NSF/PEET grant no. DEB 0328922 and associated REU supplement # 0723663. Page last updated October 2010.

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