Pseudomyrmex triplaridis

Pseudomyrmex triplaridis is always associated with - nesting and foraging upon - plants of the genus Triplaris.

Identification
Ward (1999) - Workers and queens of P. triplaridis can be identified by the combination of relatively short legs (worker LHT/HL < 0.77, queen LHT 0.86–1.04, queen LHT/HL 0.70–0.74), moderately elongate head (worker CI 0.85–0.93, queen CI 0.83–0.89), recurved anteroventral petiolar process, densely punctulate head sculpture, and presence of standing pilosity on the posterior margin and upper sides of the head (in frontal view). The palp formula of 5,3 and the more exposed median lobes of the antennal sclerites (see above; queen PFC/ASD 0.62–0.71, queen FCI2 0.45–0.60) are also characteristic. P. triplaridis is intermediate in habitus between Pseudomyrmex viduus on the one hand and the larger, broad-headed Triplaris-inhabiting species on the other hand.

Distribution
Most records for P. triplaridis are from the Amazon basin, but peripheral populations are known from Guyana and southern Brazil.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Colombia, Costa Rica, French Guiana, Guatemala, Guyana, Mexico, Panama, Suriname, Trinidad and Tobago, Venezuela.

Biology
This species is apparently always associated with Triplaris, but little has been published on its biology. Ule (1906b) found that, in contrast to P. dendroicus, the workers of P. triplaridis did not clear vegetation at the base of their host tree (see also Wheeler, 1942:49). For other information about this species see brief remarks by Forel (1904c:685, 1906:231) and Wheeler (1942:184), but note that Wheeler’s (1942:185–186) comments about ''“P. triplaridis baileyi” and “P. triplaridis tigrina” refer to Pseudomyrmex viduus, not P. triplaridis''. Collections of P. triplaridis have been made from Triplaris weigeltiana (Reichenbach) Kuntze (=T. surinamensis Chamisso) and Triplaris dugandii Brandbyge, in addition to plants identified no farther than genus. See under Pseudomyrmex ultrix for observations on incipient colonies. (Ward 1999)

Nomenclature

 *  triplaridis. Pseudomyrma triplaridis Forel, 1904e: 684 (w.q.m.) BRAZIL. Combination in Pseudomyrmex: Kusnezov, 1953e: 214. Senior synonym of boxi Wheeler (and its junior synonym boxi Enzmann): Ward, 1989: 444. See also: Wheeler, W.M. 1942: 182; Kempf, 1961a: 400; Ward, 1999b: 503.
 * boxi. Pseudomyrma triplaridis subsp. boxi Wheeler, W.M. 1942: 184 (w.q.m.) GUYANA. Combination in Pseudomyrmex: Kempf, 1961a: 400. Senior synonym of boxi Enzmann: Brown, 1949a: 43. Junior synonym of triplaridis: Ward, 1989: 444.
 * boxi. Pseudomyrma triplaridis subsp. boxi Enzmann, E.V. 1944: 94 (w.) GUYANA. [Unresolved junior primary homonym of boxi Wheeler, above.] Junior synonym of boxi Wheeler: Brown, 1949a: 43.

Worker
Ward (1999) - Measurements (n=19). HL 1.03–1.27, HW 0.89–1.14, MFC 0.080–0.116, LHT 0.72–0.95, CI 0.85–0.93, REL 0.35–0.43, REL2 0.42–0.48, FCI 0.08–0.12, SI 0.43–0.48, FLI 1.36–1.77, FI 0.39–0.43, PLI 0.80–0.92, PWI 0.84–0.97, PPWI 1.38–1.77.

Agreeing with the description of Pseudomyrmex triplarinus except as follows. Averaging smaller in size (compare HW, LHT). Palp formula 5,3. Frontal carinae less well separated, and the median lobe of antennal sclerite correspondingly more exposed (PFC/ASD 0.54–0.65, FCI2 0.45–0.61). Funicular segment 3 broader than long. Head narrower, regression of HL on HW lying above that of P. triplarinus. Metanotal groove tending to be less strongly impressed. Profemur broader (FI > 0.38). Legs relatively shorter, LHT/HL 0.70–0.75. Anteroventral petiolar process subtriangular or fin-shaped, recurved posteroventrally. Postpetiolar sternite with more conspicuous ventral protrusion. Sculpture on dorsum of head coarser, the punctures 0.010–0.020mm in diameter, subcontiguous on the anterior half of head and separated by about their diameters on upper half of head. Body pilosity common (MSC 43–70, HTC 6–13), somewhat better developed on the head than in P. triplarinus so that in frontal view the posterior margin and upper sides of the head always have some erect or subdecumbent hairs visible in outline (absent at least from the sides of the head in P. triplarinus). Pubescence on head more conspicuous, the hairs tending to be decumbent or subdecumbent, giving the worker a scruffier appearance. Less variation in body colour: more consistently concolorous mediumto dark-brown, the frontoclypeal complex and appendages typically lighter.

Type Material
Ward (1999) - Syntype workers, queens, male, Jurua Miry, Jurua, Amazonas, Brazil (Ule) [Examined].

Pseudomyrma triplaridis subsp. boxi Wheeler, 1942:184. Lectotype worker, Blairmont, Berbice, Guyana (H. E. Box) [Examined].

Pseudomyrma triplaridis subsp. boxi Enzmann, 1944:94. Syntype workers, Blairmont, Berbice, Guyana (H. E. Box) (MCZC) [Examined].