Poneracantha triangularis

A millipede feeder that is found in humid forests. The USA record (Deyrup, et. al. 1989:93) is undoubtedly a recent introduction and they have apparently found prey in the local species of millipedes, as they are well established. (Lattke 1995)

Identification
A member of the rastrata complex (in the rastrata subgroup of the rastrata species group). Promesonotal suture weakly impressed; node dorsum with transverse costulae and subquadrate costulae and subquadrate subpetiolar process; first gastric sternum with transverse costulae; metacoxal tooth long and thin. Piceous body. (Lattke 1995)

Key to New World Gnamptogenys Species

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Argentina, Bolivia, Brazil, Colombia, Costa Rica, Ecuador, French Guiana, Peru, Uruguay.

Castes
File:Gnamptogenys_triangularis__casent0006087_h_1_high.jpg|Head view File:Gnamptogenys_triangularis__casent0006087_p_1_high.jpg|Side view File:Gnamptogenys_triangularis__casent0006087_d_1_high.jpg|Top view File:Gnamptogenys_triangularis__casent0006087_l_1_high.jpg|Specimen Labels

Nomenclature

 *  triangularis. Ectatomma (Gnamptogenys) triangulare Mayr, 1887: 544 (q.) URUGUAY. Emery, 1906c: 113 (w.). Combination in E. (Parectatomma): Emery, 1911d: 44; in Gnamptogenys: Brown, 1958g: 230. Senior synonym of richteri: Brown, 1958g: 230; of aculeaticoxae: Lattke, 1995: 190.
 * richteri. Ectatomma (Parectatomma) triangulare r. richteri Forel, 1913l: 203 (w.) ARGENTINA. Forel, 1914d: 265 (q.). Junior synonym of triangularis: Brown, 1958g: 230.
 * aculeaticoxae. Ectatomma (Parectatomma) aculeaticoxae Santschi, 1921g: 82 (w.m.) FRENCH GUIANA. Wheeler, G.C. & Wheeler, J. 1971b: 1201 (l.). Combination in E. (Poneracantha): Santschi, 1929h: 476; in Gnamptogenys: Brown, 1958g: 227. Junior synonym of triangularis: Lattke, 1995: 190. See also: Lattke, 1990b: 5.

Lattke (1995) - The number of transverse costulae on the petiolar dorsum can vary from 8 to 14, and those on the pronotum from 13 to 23. Specimens from Argentina tend to have a higher count but there is no gap separating the values. The length of the coxal teeth is variable and bears no relation to the number of petiolar costulae. Propodeal teeth also show variation form a low mound to the usual low, sharp teeth. Occasional specimens can have up to 4 transverse costulae on the anterior pronotal face, and rarely longitudinal costulae on the petiolar node. Other traits used by Santschi to separate Gnamptogenys aculeaticoxae, such as degree of impression of the promesonotal suture, gastric constriction and gauge of hairs, length vs. width of petiolar node and the mandibular costulation all show continuous variation that is best described as infraspecific.