Pseudomyrmex spiculus

Identification
The combination of relatively large size, broad head, and slender petiole serves to distinguish P. spiculus from the other species in the P. subtilissimus group (Ward 1989).

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Colombia, Costa Rica, Ecuador, French Guiana, Guyana, Mexico, Panama, Peru, Suriname.

Biology
Ward (1989) - The species is widespread but infrequently collected, and little is known about its biology. Most collections are based on single individuals foraging on low vegetation or tree-falls, in rain forest, rain forest edge, littoral forest, and mangrove. In Costa Rica I collected a single dealate (colony-founding?) female in a loose dead twig, hanging in low vegetation, in coastal rain forest. Type workers from Reserva Biologica Carara were foraging on the trunk and associated vegetation of a strangler fig tree (Ficus oerstediana) and its unidentified host tree, in an old pasture. At this location, workers of Pseudomyrmex tenuissimus were present on the same vegetation, foraging in close proximity to those of P. spiculus. These two species have been collected sympatrically elsewhere, and their ranges are broadly coextensive.

Nomenclature

 *  spiculus. Pseudomyrmex spiculus Ward, 1989: 430, figs. 31-33 (w.q.) COSTA RICA.

Worker
measurements (n=14). HL 0.88-0.98, HW 0.61-0.66, MFC 0.022-0.042, CI 0.66-0.71, OI 0.55-0.61, REL 0.53-0.57, REL2 0.76-0.83, OOI 0.04-0.67, VI 0.79-0.87, FCI 0.034-0.064, SI 0.38-0.43, SI2 0.46-0.54, FI 0.48-0.55, PDI 1.20-1.61, MPI 0.029-0.059, NI 0.60-0.71, PLI 0.56-0.67, PWI 0.48-0.59, PPWI 1.14-1.37.

diagnosis. Small, slender species (HW 0.61-0.66); head elongate, although broader than that of P. tenuissimus (CI 0.66-0.7 1 ); eyes elongate, almost reaching the level of the median ocellus; occipital margin concave in full face, dorsal view; lateral margins of pronotum rounded; fore femur short and broad (FI 0.48-0.55); metanotal groove narrow, shallow; basal face of propodeum convex, declivitous face flat to weakly concave, the former about 1.5 times the length of the latter; basal face of propodeum rounding into the declivitous face at a slight (obtuse) angle, marked by a pair of erect setae; petiole slender, low, notably longer than wide (PLI 0.56-0.67); postpetiole short, globose in lateral view, subtriangular in dorsal view, about as wide as long, and twice as wide as the petiole (PWI2 0.51-0.57). Mandibles finely striate with scattered punctures, sublucid; head, mesosoma, and petiole densely punctulate to coriarious·imbricate, opaque; postpetiole and gaster opaque, with numerous fine piligerous punctures. Erect pilosity very sparse (except on apex of gaster), lacking on the antennae, sides of head, upper half of gula, femora (except for one to several setae on the ventral surface of the fore femur), tibiae, tarsi, and most of mesosoma. Two or three pairs of short erect setae on dorsum of head; a conspicuous pair of long (ca. 0.15 mm) erect setae on the anterolateral comers of pronotum, at the juncture of the basal and declivitous faces of the propodeum, and on the posterior dorsum of both the petiole and postpetiole; the last two pairs often accompanied by a pair of shorter, posterolateral setae. Appressed pubescence common on most of body, but rather fine and inconspicuous. Grey·brown; mandibles, fronto·clypeal complex, antennae, tarsi, pronotum, petiole, and postpetiole paler luteous·brown.

Type Material
Holotype Worker. COSTA RICA, Provo Puntarenas: Reserva Biologica Carara, 500m, 9°47'N, 84°36'W, 26.viii.1985, on low vegetation, old field/pasture, P. S. Ward acc. no. 7668-9. HW 0.63, HL 0.89, EL 0.50, PL 0.37, PH 0.22.

Paratype Workers, Queens. Same data as holotype, two workers; COSTA RICA, Provo Puntarenas: Manuel Antonio Natl. Park, 10m, 9°23'N, 84°09'W, 28.vii.1985, P. S. Ward acc. no. 7715-6, I worker; same locality, 40m, 27.vii. 1985, P. S. Ward acc. no. 7679, 1 dealate queen; Llorona, Corcovado Natl. Park, 10m, 10-14.v.1979, P. S. Ward acc. no. 3389-6, 1 worker; Sirena, Corcovado Natl. Park, 50m, 8°28'N, 83°35'W, 22.iv.1981, J. T. Longino, 1 worker; same locality, 20.xii.1981, J. T. Longino, 1 worker; COST A RICA, Provo Limon: Portete, 13.ii.1965, D. H. Janzen, 1 worker. .

Type series is restricted to the above material from Costa Rica. Additional, apparently conspecific material comes from Mexico, Panama, Colombia, Guyana, Brazil, and Peru.

References based on Global Ant Biodiversity Informatics

 * Adams B. J., S. A. Schnitzer, and S. P. Yanoviak. 2016. Trees as islands: canopy ant species richness increases with the size of liana-free trees in a Neotropical forest. Ecography doi: 10.1111/ecog.02608
 * Adams B. J., S. A. Schnitzer, and S. P. Yanoviak. 2019. Connectivity explains local ant community structure in a Neotropical forest canopy: a large-scale experimental approach. Ecology 100(6): e02673.
 * Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
 * Franco W., N. Ladino, J. H. C. Delabie, A. Dejean, J. Orivel, M. Fichaux, S. Groc, M. Leponce, and R. M. Feitosa. 2019. First checklist of the ants (Hymenoptera: Formicidae) of French Guiana. Zootaxa 4674(5): 509-543.
 * Gove A. D., J. D. Majer, and V. Rico-Gray. 2005. Methods for conservation outside of formal reserve systems: The case of ants in the seasonally dry tropics of Veracruz, Mexico. Biological Conservation 126: 328-338.
 * Gove, A. D., J. D. Majer, and V. Rico-Gray. 2009. Ant assemblages in isolated trees are more sensitive to species loss and replacement than their woodland counterparts. Basic and Applied Ecology 10: 187-195.
 * INBio Collection (via Gbif)
 * Vásquez-Bolaños M. 2011. Lista de especies de hormigas (Hymenoptera: Formicidae) para México. Dugesiana 18: 95-133
 * Ward, P. S. 1989. Systematic Studies on Pseudomyrmecine Ants: Revision of the Pseudomyrmex Oculatus and P. Subtilissimus Species Groups with Taxonomic Comments on Other Species. Questiones Entomologicae 25: 393-468