Poneracantha mediatrix

Apparently of lowland forests, one series taken from a varzea habitat. Its morphology puts it within the rastrata group, and it is quite probably a millipede hunter.

Identification
A member of the banksi complex (in the banksi subgroup of the rastrata species group). Mandibles elongate and triangular, their basal 2/3 rugulose and a pical 1/3 smooth and shining; clypeal lamella medianly concave; scapes with no erect hairs; petiolar costulation mostly transverse, node broader than long; metacoxal teeth very slender, propodeal teeth short. Rarely collected, it is a close relative of Gnamptogenys laticephala. (Lattke 1995)

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Ecuador.

Nomenclature

 * . Gnamptogenys mediatrix Brown, 1958g: 326, fig. 15 (w.q.) BRAZIL (Pará, Rio de Janeiro).
 * Type-material: holotype worker, 5 paratype workers, 1 paratype queen.
 * Type-locality: holotype Brazil: Pará, Belém (F. Baker); paratypes: 1 worker with same data, 3 workers Rio de Janeiro (no collector’s name), 1 worker Rio de Janeiro, Jardim Botanico (H. Souza), 1 queen Rio de Janeiro, Engenho Novo (C.R. Gonçalves).
 * Type-depositories: MCZC (holotype); MCZC, MZSP (paratypes).
 * Status as species: Kempf, 1972a: 113; Bolton, 1995b: 209; Lattke, 1995: 175; Lattke, et al. 2007: 261 (in key); Feitosa, 2015c: 98; Camacho, et al. 2020: 459 (in key).
 * Distribution: Brazil, Ecuador.

References based on Global Ant Biodiversity Informatics

 * Dias N. D. S., R. Zanetti, M. S. Santos, M. F. Gomes, V. Peñaflor, S. M. F. Broglio, and J. H. C. Delabie. 2012. The impact of coffee and pasture agriculture on predatory and omnivorous leaf-litter ants. Journal of Insect Science 13:29. Available online: http://www.insectscience.org/13.29
 * Dias N. S., R. Zanetti, M. S. Santos, J. Louzada, and J. H. C. Delabie. 2008. Interaction between forest fragments and adjacent coffee and pasture agroecosystems: responses of the ant communities (Hymenoptera, Formicidae). Iheringia, Sér. Zool., Porto Alegre, 98(1): 136-142.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Miranda P. N., F. B. Baccaro, E. F. Morato, M. A. Oliveira. J. H. C. Delabie. 2017. Limited effects of low-intensity forest management on ant assemblages in southwestern Amazonian forests. Biodivers. Conserv. DOI 10.1007/s10531-017-1368-y
 * Nascimento Santos M., J. H. C. Delabie, and J. M. Queiroz. 2019. Biodiversity conservation in urban parks: a study of ground-dwelling ants (Hymenoptera: Formicidae) in Rio de Janeiro City. Urban Ecosystems https://doi.org/10.1007/s11252-019-00872-8
 * Silva R.R., and C. R. F. Brandao. 2014. Ecosystem-Wide Morphological Structure of Leaf-Litter Ant Communities along a Tropical Latitudinal Gradient. PLoSONE 9(3): e93049. doi:10.1371/journal.pone.0093049
 * Souza J. L. P., C. A. R. Moura, A. Y. Harada, and E. Franklin. 2007. Diversity of species of the genera Crematogaster, Gnamptogenys and Pachycondyla, (Hymenoptera: Formicidae) and complementarity of sampling methods during the dry season in an ecological station in the Brazilian state of Pará. Acta Amazonica 37(4): 649-656.