Pseudomyrmex ita

Inhabits dead twigs or branches of various woody plants. It has been collected from thorns of Acacia cornigera in Mexico and A. collinsii in Costa Rica and Panama. (Ward 1993)

Identification
Ward (1993, 1999) - Workers of P. ita can be distinguished from those of Pseudomyrmex sericeus by the dorsolaterally marginate petiole with its characteristic angular profile in lateral view and straight diverging sides in dorsal view; the petiole of P. sericeus is subtriangular in profile, with more gently rounded edges. The small size (worker HW < 1.00, queen HW 0.85–0.90), closely contiguous frontal carinae, elongate eyes (worker REL > 0.62, queen REL 0.61–0.64) and relatively narrow petiole (worker DPW 0.32–0.39) are also useful traits for identification.

Distribution
Mexico to Colombia

This taxon was described from Costa Rica.

Biology
Ward (1999) - Like Pseudomyrmex gracilis, it is a generalist twig-nesting species which is occasionally found in ant-plants (Ward, 1993). Wheeler (1942) reported it from hollow twigs of Triplaris melaenodendron (as T. auriculata) at Patulul and Escuintla, Guatemala (ant specimens examined in the MCZC and their identity confirmed) and from twigs of Triplaris cumingiama (as T. americana) at Balboa, Panama (ant specimens not seen). It is unclear from Wheeler’s (1942) account whether the ants occupied live stems or dead twigs only.

Nomenclature

 *  ita. Pseudomyrma sericea var. ita Forel, 1906d: 230 (w.) COSTA RICA. Wheeler, W.M. 1942: 177 (q.). Combination in Pseudomyrmex: Kempf, 1972a: 223. Raised to species, senior synonym of acaciarum (and its junior synonym acaciorum): Ward, 1993: 158. See also: Ward, 1999b: 524.
 * acaciarum. Pseudomyrma sericea var. acaciarum Wheeler, W.M. 1942: 176 (w.q.m.) PANAMA. Combination in Pseudomyrmex: Kempf, 1972a: 223. Senior synonym of acaciorum: Brown, 1949a: 43. Junior synonym of ita: Ward, 1993: 158.
 * acaciorum. Pseudomyrma sericea var. acaciorum Enzmann, E.V. 1944: 90, pl. 3, fig. 9 (w.) PANAMA. Junior synonym of acaciarum: Brown, 1949a: 43.

Worker
Ward (1999) - Measurements (n=13). HL 1.00–1.16, HW 0.85–0.97, MFC 0.015–0.029, LHT 0.64–0.74, CI 0.83–0.86, REL 0.63–0.67, REL2 0.75–0.78, FCI 0.02–0.03, FI 0.49–0.52, PLI 0.99–1.16, PWI 0.75–0.90.

Relatively small member of the sericeus group (compared to other species considered here). Palp formula 6,4; frontal carinae closely contiguous (see MFC and FCI values); eyes and head elongate; posterior margin of head concave; dorsal face of propodeum subequal to, or shorter than, declivitous face and meeting the latter at an obtuse angle; profemur broad (FI ≈ 0.50); legs short (LHT/HL 0.62–0.68). Petiole relatively short, narrow and high (see PLI and PWI values), with sharp dorsolateral margins; petiole subtrapezoidal in profile, with anterior and dorsal faces more or less differentiated (weakly so in populations from northern Central America); dorsal face of petiole rounding sharply into the vertical posterior face. Standing pilosity very sparse; a pair of stout setae present on the pronotal humeri, petiole, and postpetiole, lacking on the mesonotum and propodeum. Dark brown-black, with lighter brown maculation variably present on the pronotum, petiole, postpetiole, fronto-clypeal complex, and appendages.

Type Material
Ward (1993) - Syntype workers, San Mateo, Costa Rica (P. Biolley) [Examined]. One syntype here designated LECTOTYPE.

Pseudomyrma sericea var. acaciarum Syntype workers, Tumba Muerta Road, Panama (W. M. Wheeler) [Examined].

Pseudomyrma sericea var. acaciorum Syntype workers, TumbaMuerta Road, Panama (W. M. Wheeler) (MCZC) [Examined].