Pseudomyrmex dendroicus

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Pseudomyrmex dendroicus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Pseudomyrmecinae
Genus: Pseudomyrmex
Species: P. dendroicus
Binomial name
Pseudomyrmex dendroicus
(Forel, 1904)

Pseudomyrmex dendroicus casent0217576 p 1 high.jpg

Pseudomyrmex dendroicus casent0217576 d 1 high.jpg

Specimen Labels


A mutualist with plants in the genus Triplaris. The ants patrol and aggressively defend the plant they nest in from intruders.

At a Glance • Ant-plant specialist  


Ward (1999) - Workers and queens of P. dendroicus and Pseudomyrmex triplarinus can be separated from all other Triplaris-inhabiting Pseudomyrmex by the longer legs and tendency towards a broader head. P. dendroicus can be distinguished from P. triplarinus by the worker characters mentioned above and in the key. Queens of the two species are more distinct, those of P. dendroicus being absolutely larger (queen HW 1.72–2.01 and queen HL 1.82–2.12 compared with HW 1.46–1.60 and HL 1.60–1.73 in P. triplarinus) and having the mandible more modified (with a strong basal incision, and more marked deformation of the upper surface of the mandible).


Widely distributed in the western Amazon basin.

Latitudinal Distribution Pattern

Latitudinal Range: -0.2508° to -14.5°.

Tropical South

Distribution based on Regional Taxon Lists

Neotropical Region: Brazil (type locality), Colombia, Ecuador, Peru.

Distribution based on AntMaps


Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.


Ward (1999) - P. dendroicus is a strict Triplaris associate that co-occurs with Pseudomyrmex triplarinus and Pseudomyrmex triplaridis at some localities. The workers prune vegetation around the host tree, leaving a cleared area at the base of the tree (Ule, 1906b). Davidson et al. (1988) present experimental evidence that this behaviour reduces the invasion success of dominant (and generalist, non-mutualistic) neighbouring ants such as Crematogaster. Additional information on the biology of P. dendroicus is contained in papers by Ule (1906b, 1907), Wheeler (1942), Schremmer (1984) and Davidson et al. (1988, 1989). Schremmer’s investigations of P. triplarinus from Villavicencio, Colombia refer to P. dendroicus, while his observations of P. triplarinus from Since, Colombia represent another species, Pseudomyrmex mordax. Most museum specimens of P. dendroicus are labeled as coming from “Triplaris” (unidentified to species) but some collections are associated specifically with Triplaris americana Linnaeus, including those of Brandbyge, Davidson, Toft, Ule and Ward (part).


Images from AntWeb

Pseudomyrmex dendroicus casent0904052 d 1 high.jpgPseudomyrmex dendroicus casent0904052 h 1 high.jpgPseudomyrmex dendroicus casent0904052 p 1 high.jpgPseudomyrmex dendroicus casent0904052 l 1 high.jpg
Paralectotype of Pseudomyrmex dendroicusWorker. Specimen code casent0904052. Photographer Will Ericson, uploaded by California Academy of Sciences. Owned by MSNG, Genoa, Italy.
Pseudomyrmex dendroicus casent0907526 h 1 high.jpgPseudomyrmex dendroicus casent0907526 d 1 high.jpgPseudomyrmex dendroicus casent0907526 p 1 high.jpgPseudomyrmex dendroicus casent0907526 l 1 high.jpg
Lectotype of Pseudomyrmex dendroicusWorker. Specimen code casent0907526. Photographer Will Ericson, uploaded by California Academy of Sciences. Owned by MHNG, Geneva, Switzerland.


The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • dendroicus. Pseudomyrma dendroica Forel, 1904c: 40 (w.m.) BRAZIL. Combination in Pseudomyrmex: Kempf, 1961a: 408. Junior synonym of triplarinus: Kempf, 1961a: 408. Revived from synonymy and senior synonym of emarginata: Ward, 1989: 436. See also: Ward, 1999b: 490.
  • emarginata. Pseudomyrma dendroica var. emarginata Forel, 1904e: 684 (w.q.) BRAZIL. Junior synonym of triplarinus: Kempf, 1961a: 408; of dendroicus: Ward, 1989: 436.

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=34). HL 1.09–1.55, HW 1.07–1.51, MFC 0.126–0.196, LHT 0.92–1.36, CI 0.94–1.04, REL 0.40–0.46, REL2 0.41–0.45, FCI 0.11–0.14, SI 0.42–0.48, FLI 1.74–2.24, FI 0.35–0.40, PLI 0.70–0.85, PWI 0.72–0.86, PPWI 1.29–1.76.

Similar to Pseudomyrmex triplarinus (q.v.) except as follows. Posterior margin of head more markedly concave (frontal view). Frontal carinae better separated, on average. Scape tending to be longer in relation to HL. Petiole less expanded posterolaterally. Subpetiolar process generally subrectangular or fin-shaped, and pointing posteroventrally. Punctulate sculpture slightly denser on upper third of head, on average. Standing pilosity longer but less common, MSC 7–53, HTC 1–11, absent from the posterior margin of the head; erect hairs on the petiole and postpetiole tending to be more notably curved. Head (except for mandibles, scapes and frontoclypeal complex) brown to dark brown and nearly always contrasting with the lighter-coloured mesosoma.

Type Material

Ward (1999) - Lectotype worker, Rio Purus, Brazil (A. Goldi) (Musee d'Histoire Naturelle Genève) [Examined].

Pseudomyrma dendroica var. emarginata Forel, 1904c:684. Syntype workers, queen, Mavany Jurua, Amazonas, Brazil (Ule) (Museo Civico di Storia Naturale, Genoa, MHNG) [Examined].


References based on Global Ant Biodiversity Informatics

  • Davidson D. W., S. C. Cook, R. R. Snelling and T. H. Chua. 2003. Explaining the Abundance of Ants in Lowland Tropical Rainforest Canopies. Science 300: 969-972.
  • Ward P. S. 1999. Systematics, biogeography and host plant associations of the Pseudomyrmex viduus group (Hymenoptera: Formicidae), Triplaris- and Tachigali-inhabiting ants. Zoological Journal of the Linnean Society 126: 451-540