Solenopsis fugax species complex

The following is based on: Pacheco, J.A. & Mackay, W.P. 2013. The systematics and biology of the New World thief ants of the genus Solenopsis (Hymenoptera: Formicidae). Edwin Mellen Press, Lewiston, New York. 501 pp. PDF

Solenopsis fugax Species Complex / Key to workers / Clave a las obreras

This is a group of New World thief ants in the genus Solenopsis.

Diagnosis - Workers of this group have the head wider than long (may be only slightly longer than wide) with the posterior border straight. The dorsum of the head is coarsely punctate. There are four well-developed teeth on the anterior border of the clypeus typically (occasionally the extralateral teeth are reduced to bumps or are angulate). The eyes range from 1-10 ommatidia. The notopropodea1 suture is typically deeply depressed. The petiolar peduncle typically contains a tooth or flange ventrally. The postpetiole is oval-shaped (round in S. pergandei) and slightly wider than the petiole (viewed dorsally). Nearly all of the New World species are yellow (with the exception of S. vinsoni, S. germaini and S. westwoodi), moderately to very pilose and size varies, although they are relatively large (1.1-2.5 mm total length). Several members of this species complex are dimorphic (majority apparently monomorphic) with majors that are distinct morphologically from the minor workers.

Two species, S. rugiceps and the major worker of S. vinsoni, contain rugulae on the dorsum of the head, a character restricted to these two species in the thief ants. Additionally S. vinsoni contains rugulae on the petiole and postpetiole (viewed laterally).

The females of these species, where they are known, are very large (> 5 mm, most ~ 7 mm total length). The males of these species (although rarely collected) can be large as well (up to 5 mm).

Solenopsis fugax is a European species and is similar morphologically to these New World forms and thus is the name given for this species complex.

Solenopsis orestes is a species that has intermediate characters between the molesta and fugax complexes (it has angulate extralateral clypeal teeth and coarse cephalic punctures) and is placed in both the keys for the molesta and fugax species complexes.