First Record of The AntRhopalothrix weberi(Hymenoptera: Formicidae: Myrmicinae) for Mexico

Abstract

The genus Rhopalothrix Mayr is a member of the monophyletic tribe Basicerotini (Bolton 1998). It is a rare group of ants with 10 known species, 7 of which are distributed across Central and South America and the rest in the Indo-Aus tralian region. The biology of this genus is not well known, but it seems to exhibit the same predatory habits as other members of the tribe; the few basicerotines whose habits are known are predators of small, soft-bodied arthropods (Wil son 1956; Brown & Kempf 1960; Wilson & Brown 1985; Longino 1999). Ants of this genus have 7-segmented antennae that, when reclined against the head in their nor mal position, are sustained on the antenn?i scrobes that run beneath the eyes. Their mandi bles are slender and elongate; when completely shut, they remain separated due to a cavity that runs along most of their length and touches only at the tips. These ants are similar to Eurhopalo thrix, but with thinner, more elongate, triangular jaws. In this paper we report the first record of Rho palothrix weberi Brown and Kempf for Mexico. Until now, the only known record of the genus in this country was for R. stannardi in the state of Chiapas (Brown & Kempf 1960). During a sam pling project to study the ant fauna associated with patches of cloud forest in the central part of the state of Veracruz, 1 worker of this species was collected from a litter sample processed in Win kler bags. Although we processed more than 120 samples of litter from cloud forest and coffee plan tations in this zone, only 1 specimen was ob tained. The collection of these ants tends to be quite scattered; as in this case, they are generally found as isolated individuals obtained from litter samples processed in Winkler traps or Berlesse funnels (Longino 1999; Brown & Kempf 1960). The R. weberi worker was collected near El Olmo, situated on the road between Teocelo and Ixhuacan de Los Reyes in the municipality of the same name (latitude 19 20 5 ; longitude 97?01' 42W), at an altitude of 1300 m (Aug 12, 2008, J. Valenzuela Col.). It was sampled in a patch of cloud forest of about 8 ha located on hilltops sur rounded by coffee plantations. The ant was identified with keys and descrip tions provided by Brown & Kempf (1960) as well as Weber's original description of this species, as Heptastruma wheeleri (Weber 1934). The speci men has the following features characteristic of the description of R. weberi. The dorsum of head with a pair of well-defined transverse ridges; clypeus without conspicuous subappressed, oval setae; labrum with a deep median cleft or notch that extends inward from its apex nearly to its midlength with rounded lateral lobes (Fig. 1);