Pseudomyrmex ita

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Pseudomyrmex ita
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Pseudomyrmecinae
Genus: Pseudomyrmex
Species: P. ita
Binomial name
Pseudomyrmex ita
(Forel, 1906)

Pseudomyrmex ita lacm ent 142434 profile 1.jpg

Pseudomyrmex ita lacm ent 142434 dorsal 1.jpg

Specimen labels


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). Gillette et al. (2015) in a Chaipas, Mexico field study of twig-nesting ants in coffee plants found C. striatus nesting on plants between 600-900 m in elevation.


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.


Mexico to Colombia

Distribution based on Regional Taxon Lists

Neotropical Region: Belize, Brazil, Colombia, Costa Rica (type locality), El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Paraguay.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb


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.



The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • 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.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.



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) (Musee d'Histoire Naturelle Genève) [Examined]. One syntype here designated LECTOTYPE.

Pseudomyrma sericea var. acaciarum Syntype workers, Tumba Muerta Road, Panama (W. M. Wheeler) (Los Angeles County Museum of Natural History, Museum of Comparative Zoology) [Examined].

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


  • Forel, A. 1906d. Fourmis néotropiques nouvelles ou peu connues. Ann. Soc. Entomol. Belg. 50: 225-249 (page 230, worker described)
  • Gillette, P. N., K. K. Ennis, G. D. Martinez, and S. M. Philpott. 2015. Changes in Species Richness, Abundance, and Composition of Arboreal Twig-nesting Ants Along an Elevational Gradient in Coffee Landscapes. Biotropica. 47:712-722. doi:10.1111/btp.12263
  • Kempf, W. W. 1972b. Catálogo abreviado das formigas da regia~o Neotropical. Stud. Entomol. 15: 3-344 (page 223, Combination in Pseudomyrmex)
  • Ward, P. S. 1993. Systematic studies on Pseudomyrmex acacia-ants (Hymenoptera: Formicidae: Pseudomyrmecinae). J. Hym. Res. 2: 117-168 (page 158, Raised to species, and senior synonym of acaciarum (and its junior synonym acaciorum))
  • Ward, P. S. 1999b. Systematics, biogeography and host plant associations of the Pseudomyrmex viduus group (Hymenoptera: Formicidae), Triplaris- and Tachigali-inhabiting ants. Zool. J. Linn. Soc. 126: 451-540 (page 524, see also)
  • Wheeler, W. M. 1942. Studies of Neotropical ant-plants and their ants. Bull. Mus. Comp. Zool. 90: 1-262 (page 177, queen described)