Pseudomyrmex evitus Ward, sp. nov.

(Fig. 2)

Pseudomyrmex sp. PSW-02; Ward (1993: 135). Male genitalia similar to those of P. ferrugineus group. Pseudomyrmex psw002; Chomicki et al. (2015: 4). Nested phylogenetically in P. ferrugineus group.

Type material. Holotype worker. COSTA RICA Heredia: Est. Biol. La Selva, 50–150m, 10°26ʹN 84°01ʹW, Mar 1994 [in recent treefall, tropical rainforest], INBio-OET, J. Longino JTL03593 (INBC) (INBIOCRI001271962). Paratypes. Series of 7 workers, same data as holotype (CASC, JTLC, INBC, PSWC, UCDC).

Other material examined. (BMNH, INBC, JTLC, MUCR, PSWC, UCDC, USNM). MEXICO Chiapas: Playón de la Gloria, 180m (LLAMA); Tabasco: Teapa (H. H. Smith); Veracruz: Estación de Biología Los Tuxtlas, 115 m (P. S. Ward); Los Tuxtlas, 10 km NNW Sontecomapan, 200 m (P. S. Ward); BELIZE Cayo: Las Cuevas, 5 km SE Millionario (C. Lyal & D. Hollis); GUATEMALA Petén: Tikal (T. H. Hubbell); Tikal Natl. Park, 270 m (J. Longino); HONDURAS Atlántida: Carmelina (W. M. Mann); Comayagua: PN Cerro Azul Meambar, 1170 m (LLAMA); COSTA RICA Heredia: 11 km ESE La Virgen, 300 m (ALAS); 2 km NW Pto. Viejo, 50 m (G. Gomez); 22 km N Volcan Barba, 500 m (J. Longino); Chilamate, 75 m (Hanson & Godoy).

Worker measurements (n = 14). HL 1.13–1.25, HW 1.15–1.28, MFC 0.040–0.070, LHT 0.91–1.00, CI 1.01– 1.0 5, REL 0.52–0.55, REL2 0.51–0.54, FCI 0.033–0.056, FI 0.42–0.45, PLI 0.49–0.56, PWI 0.50–0.60.

Worker diagnosis. Medium-sized species (see HL, HW and LHT measurements) with broad head (CI>1.00) and elongate eyes (REL>0.50); anterior margin of median clypeal lobe concave, and laterally angulate; palp formula 4,3; frontal carinae separated by less than basal scape width; profemur relatively robust; mesosoma as in Fig. 2 b, metanotal groove weakly impressed; dorsal face of propodeum slightly longer than, and rounding into, declivitous face; petiole as in Fig. 2 b, about twice as long as high or wide, anterodorsal face ascending gradually, without a well differentiated anterior peduncle; dorsal surface of petiole with a weak median furrow; postpetiole broad, about 1.6–1.7× petiole width. Head, mesosoma and petiole densely punctulate-coriarious and mostly opaque; postpetiole and abdominal tergite IV similarly opaque, their reflectance dulled by fine punctulae and associated dense pubescence. Standing pilosity fine, pale, and moderately common on most parts of the body (MSC 13–26), present on the mesonotum and (usually) propodeum. Dark brownish-black, the appendages medium brown.

Comments. This species is readily recognized by the combination of the shape of the clypeal lobe (medially concave and laterally angulate); broad head; dense coriarious-punctulate sculpture which renders the body opaque; and petiole shape (Fig. 2 b). The reduced palp formula, elongate eyes, weakly impressed metanotal groove, and uniformly dark coloration are also distinctive. P. feralis, the other non-mutualist species in the P. ferrugineus group, is similar to P. evitus in the shape of the clypeus and mesosoma, but it is smaller (HW 0.94–0.99) with less heavily sculptured integument, shorter legs (LHT 0.73–0.77), and a more elongate head (CI 0.90–0.94). Males of P. evitus have an unusually elongate third (penultimate) segment of the maxillary palps, which is about 2.6× the length of the terminal segment.

Distribution and biology. P. evitus is an uncommon species, known from scattered locations from southern Mexico to Costa Rica. Collections come from tropical moist forest, lowland rainforest, lowland rainforest edge, and montane rainforest, at elevations ranging from 50 m to 1170 m. I have encountered this species in the field only at Estación de Biología Los Tuxtlas, Veracruz, Mexico, where I found single foragers on the ground and on a tree trunk, and a nest in a dead twig. In contrast to the acacia-ants the workers of P. evitus have a timid disposition.