Gnamptogenys triangularis is a relatively large, black ant with more reddish legs that is characterized by deep longitudinal grooves and ridges that the run the lengths of the head, mesosoma and gaster. Little is known about the ecology of the ant, other than that it is believed to be a millipede specialist and is associated with humid forests and arboreal foraging (Costello et al., 2003; Deyrup et al., 2000; Lattke et al., 2004; Longino, 2012). Gnamptogenys triangularis is native to the Neotropics, where it ranges from Costa Rica to Argentina (Lattke et al., 2007), and is introduced in Florida (Deyrup, 2003; Deyrup et al., 2000; Deyrup et al., 1989), Alabama (MacGown & Forster, 2005), and Mississippi (MacGown, 2012). The earliest known specimens from Florida (first reported as G. aculeaticoxae (Santschi)) date to 1985, and it is so rare there that it is believed to have negligible effects on the native fauna (Deyrup et al., 2000).
Native range. Neotropics: Costa Rica to Argentina.
Introduced range. USA: Alabama, Florida, Mississippi.
Costa Rica: La Selva and Osa Peninsula.
Costa Rica (Jack Longino)
Lattke (1995) reports this species as a millipede specialist found in humid forests. In Corcovado National Park, I observed a worker with milliped prey. triangularis has been introduced in south Florida (Deyrup et al. 1989).
The Costa Rican records I have of this species are as follows:
Puntarenas: Sirena, Corcovado National Park, 8¡29'N, 83¡36'W, 5m (J. Longino). (1) Worker on log. (2) Single worker with millipede prey. (3) Workers on large tree trunk. (4) Canopy Ficus; dealate queen walking on branch.
Lattke (1995) reports a collection from La Selva Biological Station.
Diagnosis among workers of introduced and commonly intercepted ants in the United States. Antenna 12-segmented. Antennal insertions at least partly covered by frontal lobes. Anterior margin of clypeus not denticulate. Eyes medium to large (greater than 5 facets); situated at or above midline of head. Mandibles triangular. Metanotum does not form a prominent convexity bordered by distinct suture lines. Propodeum armed with small teeth or denticles. Waist 1-segmented. Petiole narrowly attached to gaster; has conspicuous posterior face. Petiolar node relatively quadrate and subpetiolar process broad in profile with a blunt anterior angle and an acute posterior angle. Subpetiolar process narrow with a blunt posterior angle and lacking a distinct anterior angle. Abdominal segment 4 with deep longitudinal furrows; distinct constriction between abdominal segments 3+4. Gaster armed with sting. Tarsal claws with subapical tooth. Hind coxae armed with dorsal spine.
Gnamptogenys triangularis, and its geographic and morphological variation, is treated in the taxonomic works of Brown (1958)and Lattke (2004; Lattke et al., 2007). In particular it should be noted that the propodeal teeth vary in size from small denticles to well-formed teeth. The only other species of Gnamptogenys in North America is G. hartmani (Wheeler, W.M.), from which G. triangularis can be separated by its much larger size, shorter erect hairs, and the presence of propodeal teeth. Among other introduced ants, G. triangularis might be most confused with ponerine genera, but can be separated by the eyes which are above the midline of the head, the distinct sulcate sculpture, the coxal tooth, and the deep constriction between abdominal segments 3+4. Among commonly intercepted ants, G. triangularis is most likely confused with Ectatomma species, but can be separated by the lack of convexity and suture lines of the mesonotum, the presence of the coxal spines, and the sulcate sculpture.
Brown, W.L., Jr. (1958) Contributions toward a reclassification of the Formicidae. II. Tribe Ectatommini (Hymenoptera). Bull. Mus. Comp. Zool., 118, 173-362.
Costello, S.L., Pratt, P.D., Rayamajhi, M.B. & Center, T.D. (2003) Arthropods associated with above-ground portions of the invasive tree, Melaleuca quinquenervia, in South Florida, USA. Florida Entomol., 86, 300-322.
Deyrup, M. (2003) An updated list of Florida ants (Hymenoptera: Formicidae). Florida Entomol., 86, 43-48.
Deyrup, M., Davis, L. & Cover, S. (2000) Exotic ants in Florida. Trans. Am. Entomol. Soc., 126, 293-326.
Deyrup, M., Johnson, C., Wheeler, G.C. & Wheeler, J. (1989) A preliminary list of the ants of Florida. Florida Entomol., 72, 91-101.
Lattke, J.E. (1995) Revision of the ant genus Gnamptogenys in the New World (Hymenoptera: Formicidae). J. Hym. Res., 4, 137-193.
Lattke, J.E., Fernandéz C., F. & Palacio, E.E. (2004) Una nueva especie de Gnamptogenys (Hymenoptera: Formicidae) y comentarios sobre las especies del génereo en Colombia y Ecuador. Iheringia Ser. Zool., 94, 341-349.
Lattke, J.E., Fernández, F. & Palacio G., E.E. (2007) Identification of the species of Gnamptogenys Roger in the Americas. In: Snelling, R.R., Fisher, B.L. & Ward, P.S. (Eds.) Advances in ant systematics (Hymenoptera: Formicidae): homage to E. O. Wilson - 50 years of contributions. Memoirs of the American Entomological Institute, vol. 80, Gainesville, FL, 690 p., pp. 254-270.
Longino, J.T. (2012) Antweb. Ants of Costa Rica. Retrieved from: http://www.antweb.org/costarica.jsp (accessed June 2012)
MacGown, J.A. (2012) Ants (Formicdae) of the Southereastern United States
MacGown, J.A. & Forster, J. (2005) A preliminary list of the ants (Hymenoptera: Formicidae) of Alabama, U.S.A. Entomol. News, 116, 61-74.
Mayr, G. (1887) Südamerikanische Formiciden. Verh. K.K. Zool. Bot. Ges. Wien, 37, 511-632.
Santschi, F. (1921) Ponerinae, Dorylinae et quelques autres formicides néotropiques. Bull. Soc. Vaudoise Sci. Nat., 54, 81-103.
Found most commonly in these habitats: 1 times found in forest, 1 times found in Port of entry, 1 times found in wet forest
Collected most commonly using these methods or in the following microhabitats: 4 times Search, 1 times Winkler
Elevations: collected from 215 - 1150 meters, 805 meters average