Pseudomyrmex cubaensis

This species nests in hollow cavities of dead vegetation.

Identification
See the nomenclature section below.

Distribution
This species occurs in the Greater Antilles and Bahamas, and has been introduced into south Florida (Ward 1985). The Florida population is isolated from the others. It is common in coastal mangroves and could have arrived in Florida in floating trees. Moreover, Simberloff and Wilson (1969) showed that this species is likely to be a regular and early colonists of isolated mangrove islets, and must therefore have the habit of flying over open water for hundreds, if not thousands of meters. On the other hand, colonies can be found in small dead twigs on live trees and shrubs and the chance of importation in nursery stock is good. (Deyrup, Davis & Cover, 2000.)

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Argentina, Bahamas, Bolivia, Brazil, Colombia, Costa Rica, Cuba, Dominican Republic, Greater Antilles, Guatemala, Haiti, Mexico, Panama, Paraguay, Peru, Venezuela.



Biology
Ward (1985) - In Florida, I have collected P. cubaensis in dead twigs of Rhizophora mangle and Conocarpus erectus. There are museum records of nests in Tillandsia (Florida) and Cladium (Bahamas), and of workers foraging on Ficus aurea, mangrove, sea grape, and acacia. Wheeler's (1905) records of Bahamaian "elongatus" in culms of Uniola and Cladium and in hollow twigs of gum mastic, sea grape, and buttonwood, refer in part to P. cubaensis (see also discussion of Pseudomyrmex subater Wheeler & Mann under Pseudomyrmex elongatus).

Ward (1989) - In the Caribbean region, colonies of P. cubaensis occupy dead stems of various woody and herbaceous plants (Ward, 1985), often in littoral environments. Mainland populations come from a variety of habitats, including tropical dry forest, savannah, roadside verge, second-growth lowland rain forest, rain forest edge and montane rain forest edge. Nesting habits of these mainland populations are probably also generalized, but unfortunately most records consist of foraging workers rather than nest series.

Nomenclature

 *  cubaensis. Pseudomyrma elongata var. cubaensis Forel, 1901e: 342 (w.) CUBA. Forel, 1913l: 215 (q.); Wheeler, G.C. & Wheeler, J. 1956: 384 (l., misidentified as elongatus). Combination in Pseudomyrmex: Creighton, 1957b: 18. Junior synonym of elongatus: Creighton, 1957b: 18. Revived from synonymy and raised to species: Ward, 1985b: 226. See also: Ward, 1989: 413.

Ward (1985):

Originally described as a variety of Pseudomyrmex elongatus, Pseudomyrmex cubaensis was synonymized with the former by Creighton (1955, p.18). However it appears to be consistently distinct from the smaller elongatus-like form with which occurs sympatrically in south Florida. The most important differences are in the relative length of the eye and the shape of the petiole. A two-dimensional plot of REL2 and PLI cleanly separates all Floridian and most other material into two taxa. In Jamaica the two forms are less distinct. It is possible that P. elongatus and P. cubaensis represent a remnant circular Rassenkreis stretching around the Gulf of Mexico, with intermediate populations in Jamaica.

Apart from the differences in eye length and petiole shape, P. cubaensis also tends to have a broader head, narrower fore femur (FI 0.42-0.48), longer post petiole (PPWI 1.01-1.25), and fewer (but longer) erect setae on the petiole, postpetiole, and fourth abdominal tergite. The body sculpture and appressed pubescence are lighter than in Florida Pseudomyrmex elongatus, producing a shinier appearance, particularly on the occiput, propleuron, petiole, and postpetiole. (Elsewhere P. elongatus may have an equally shiny integument. e.g. in Texas.)

Ward (1989):

P. cubaensis (s.l.) can be diagnosed minimally by the combination of medium size (HW 0.65-0.78); a punctate-sublucid head; relatively short eyes (REL2 0.65-0.76); moderately broad fore femur (FI 0.41-0.50); and petiole with rounded dorsolateral margination. The largest workers of P. cubaensis (s.l.) from South America overlap in size with the smallest workers of Pseudomyrmex curacaensis; they are distinguished from the latter by the possession of a broader fore femur, longer head, flatter occipital margin, shorter funicular segments, and gentler dorsolateral margination of the petiole (see discussion under P. curacaensis). At the lower limits of its size range, ''P. cubaensis (s.l.) can be difficult to distinguish from Pseudomyrmex urbanus''. Workers of the latter have broader fore femora and longer eyes for a given head width, compared to P. cubaensis (s.l.).

Workers of P. cubaensis (s.l.) differ from those of P. elongatus by their larger average size, shorter eyes and lower petiole height in the region of size overlap, and sublucid head and mesosoma.

Worker
Ward (1989) - measurements, Florida and Caribbean (cubaensis s.s.) (n=24). —HL 0.89-1.02, HW 0.65-0.73, MFC 0.017-0.029, CI 0.71-0.75, OI 0.52-0.58, REL 0.47-0.51, REL2 0.65-0.71, OOI 0.41-0.95, VI 0.74-0.84, FCI 0.024-0.044, SI 0.44-0.48, SI2 0.64-0.74, FI 0.42-0.48, POI 1.09-1.44, MPI 0.038-0.084, NI 0.53-0.63, PLI 0.67-0.78, PWI 0.55-0.71, PPWI 1.01-1.28.

measurements, mainland Latin America (n=31). - HL 0.82-1.06, HW 0.65-0.78, MFC 0.015-0.031, CI 0.69-0.79, OI 0.53-0.60, REL 0.50-0.56, REL2 0.66--0.76, OOI 0.16-0.73, VI 0.75-0.86, FCI 0.022-0.044, SI 0.44-0.50, SI2 0.60-0.72, FI 0.41-0.50, POI 1.12-1.51, MPI 0.038--0.066, NI 0.54-0.68, PLI 0.75-0.88, PWI 0.57-0.71, PPWI 1.13-1.36.

(cubaensis s.s.). Medium-sized species (HW 0.65 - D.73), with elongate head and relatively short eyes (REL 0.47-0.51); sides of head shallowly convex, occipital margin flat to slightly concave, in frontal view; funicular segments II and III broader than long. Fore femur only moderately swollen; metanotal groove conspicuously impressed; basal face of propodeum more or less flat, raised slightly or not at all above level of mesonotum, rounding gently into the declivitous face which it exceeds in length. Petiole apenduculate, with a conspicuous anteroventral process (blunt or tooth-like), node rather long relative to its height (see metrics), and with gentle dorsolateral margination; postpetiole slightly longer than broad.

Mandibles striato-punctate; head densely punctate, subopaque to sublucid, with rather conspicuous shiny interspaces between the punctures on the upper third of the head, especially between the ocelli and the compound eye and immediately posterior to the eye. Mesosoma punctate to coriarious-imbricate, subopaque, with sublucid areas on the side of the pronotum and centre of the pronotum and mesonotum: petiolar node sublucid, especially its posterior face; postpetiole and gaster sublucid, covered with numerous fine piligerous punctures. Fine erect pilosity and appressed pubescence covering most of body, including mesosoma dorsum. Medium to dark brown, the antennae, mandibles, and tarsi lighter in color.

The above description applies to the populations of P. cubaensis inhabiting Florida and the Caribbean. Elsewhere, in Mexico, Central America, and South America is a variable array of cubaensis-like populations which I currently treat as conspecific with the Caribbean form. Workers in these mainland populations tend to have longer eyes and a shorter and higher petiole (compare REL, REL2, and PLI in the lists of measurements given above). They also tend to be lighter in color, especially in South America where some populations contain rather large orange-brown workers, quite different in appearance from Caribbean P. cubaensis. Taken together as a whole, however, these mainland populations overlap in size, shape, and color with the more typical P. cubaensis, and I find no clear discontinuities in the available (largely worker-based) material. Future work involving the analysis of queens, males, or biochemical characters might well reveal several cryptic species.

Type Material
Ward (1985) - Holotype (unique syntype) worker, Bahia Honda, Cuba [Examined].