Thaumatomyrmex atrox

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Thaumatomyrmex atrox
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Ponerinae
Tribe: Ponerini
Genus: Thaumatomyrmex
Species: T. atrox
Binomial name
Thaumatomyrmex atrox
Weber, 1939

Thaumatomyrmex atrox casent0010852 profile 1.jpg

Thaumatomyrmex atrox casent0010852 dorsal 1.jpg

Specimen labels

At a Glance • Gamergate  


Photo Gallery

  • Thaumatomyrmex atrox worker. Photo by Alex Wild.
  • Colonies may have fewer than 10 individuals. Workers lurk in the leaf litter of South American rainforests hunting only polyxenid millipedes. The ultimate specialist! Photo by Alex Wild.


Kempf (1975) - The presence of a basal denticle on mandibles, the semicircular rugulae between frontal carinae and eyes, and the shallow, circular depression on posterior surface of petiolar node still allow for a clear-cut separation of atrox from Thaumatomyrmex ferox.

Keys including this Species


Latitudinal Distribution Pattern

Latitudinal Range: 18.7942° to -64.36°.

Tropical South

Distribution based on Regional Taxon Lists

Neotropical Region: Colombia, Costa Rica, Guyana (type locality), Panama, Venezuela.

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.





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

  • atrox. Thaumatomyrmex atrox Weber, 1939a: 98, fig. 3 (w.) GUYANA, TRINIDAD.
    • Type-material: holotype worker, 1 paratype worker.
    • Type-locality: holotype Guyana (“British Guiana”): Kartabo Point, junction of Mazaruni and Cuyuni Rivers, 20.viii.1935 (N.A. Weber); paratype Trinidad: foothills N Tunapuna, 29.vii.1935 (N.A. Weber).
    • Type-depository: MCZC.
    • Status as species: Weber, 1942b: 67; Smith, M.R. 1944b: 98 (in key); Kempf, 1972a: 250; Kempf, 1975b: 122 (redescription); Longino, 1988: 38; Brandão, 1991: 382; Brandão, Diniz & Tomotake, 1991: 339; Bolton, 1995b: 420; Mackay, Mackay, et al. 2008: 212; Jahyny, et al. 2008: 333; Bezděčková, et al. 2015: 125; Fernández & Guerrero, 2019: 548.
    • Distribution: Colombia, Guyana, Peru, Trinidad.



Kemp (1975): paratype. TL 4.4 mm; HL 0.91 mm; HW 1.09 mm; CI 120; ML 1.15 mm; MI 126; IfW 0.65 mm; IfI 60; SL 0.80 mm; SI 88; WL 1.33 mm; PnW 0.64 mm; HfL 0.97 mm; HfI 89; PW 0.73 mm. Extremely close to ferox from which it differs in the following characters:

Head slightly narrower (CI) and mandibles somewhat shorter (MI). The mandibles with a small tooth at base of proximal spine, the intermediate spine not sinuous, almost as long as one half the chord length of apical spine. Rugulae on frontal lobes prolonged caudad by curving laterad towards upper (inner) border of eyes and circumscribing the antennal socket. Greatest length of head both between anteriormost point of frontal lobes and of mandibular acetabula and the posteriormost point of occipital carina. Petiole with the anterior surface of node transversely convex, in profile almost straight (Fig. 26), apex medium rounded, posterior surface as seen from above concave, as seen from the side somewhat convex, showing on its disc a large, shallow circular depression.

Facet count across greatest diameter of eyes: 12 facets in a row. Metanotal groove present. Thorax as in ferox.

Kempf 1975 Thaumatomyrmex 2.jpg Kempf 1975Thaumatomyrmex 3.jpg Kempf 1975 Thaumatomyrmex 4.jpg

Type Material

Kemp (1975): GUIANA: junction of the Mazaruni and Cuyuni rivers, August 20, 1935, among leaves, N. A. Weber leg. 1 female (holotype, Weber collection: Museum of Comparative Zoology). Trinidad: foothills north of Tunapuna, July 29, 1935, among leaves, N. A. Weber leg. 1 female (paratype: WWK, received from Museum of Comparative Zoology); paratype examined.


References based on Global Ant Biodiversity Informatics

  • Alonso L. E., J. Persaud, and A. Williams. 2016. Biodiversity assessment survey of the south Rupununi Savannah, Guyana. BAT Survey Report No.1, 306 pages.
  • Basset Y., L. Cizek, P. Cuenoud, R. K. Didham, F. Guilhaumon, O. Missa, V. Novotny, F. Odegaards, T. Roslin, J. Schmidl et al. 2012. Arthropod diversity in a tropical forest. Science 338(6113): 1481-1484.
  • Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
  • Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology
  • Delabie J. H. C., D. Fresneau, and A. Pezon. 2000. Notes on the ecology of Thaumatomyrmex spp. (Hymenoptera: Formicidae: Ponerinae) in Southeast Bahia, Brazil. Sociobiology 36(3): 571-584.
  • Donoso D. A. 2014. Assembly mechanisms shaping tropical litter ant communities. Ecography 37 doi: 10.1111/j.1600-0587.2013.00253.x
  • Fernandes I., and J. de Souza. 2018. Dataset of long-term monitoring of ground-dwelling ants (Hymenoptera: Formicidae) in the influence areas of a hydroelectric power plant on the Madeira River in the Amazon Basin. Biodiversity Data Journal 6: e24375.
  • Fernández F. 2008. Subfamilia Ponerinae s.str. Pp. 123-218 in: Jiménez, E.; Fernández, F.; Arias, T.M.; Lozano-Zambrano F. H. (eds.) 2008. Sistemática, biogeografía y conservación de las hormigas cazadoras de Colombia. Bogotá: Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, xiv + 609 pp.
  • Fernández F., E. E. Palacio, W. P. MacKay, and E. S. MacKay. 1996. Introducción al estudio de las hormigas (Hymenoptera: Formicidae) de Colombia. Pp. 349-412 in: Andrade M. G., G. Amat García, and F. Fernández. (eds.) 1996. Insectos de Colombia. Estudios escogidos. Bogotá: Academia Colombiana de Ciencias Exactas, Físicas y Naturales, 541 pp
  • Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
  • Guerrero R. J., and C. E. Sarmiento. 2010. Distribución altitudinal de hormigas (Hymenoptera, Formicidae) en la vertiente noroccidental de la Sierra Nevada de Santa Marta (Colombia). Acta Zoologica mexicana (n.s.) 26(2): 279-302.
  • INBio Collection (via Gbif)
  • Jahyny B., S. Lacau, J. H. C. Delabie, and D. Fresneau. 2008. Le genre Thaumatomyrmex Mayr 1887, cryptique et prédateur spécialiste de Diplopoda Penicillata. Pp. 329-346 in: Jiménez, E.; Fernández, F.; Arias, T.M.; Lozano-Zambrano, F. H. (eds.) 2008. Sistemática, biogeografía y conservación de las hormigas cazadoras de Colombia. Bogotá: Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, xiv + 609 pp.
  • Kempf W. W. 1975. A revision of the Neotropical ponerine ant genus Thaumatomyrmex Mayr (Hymenoptera: Formicidae). Studia Entomologica 18: 95-126.
  • Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
  • Longino J. T. 1988. Notes on the taxonomy of the neotropical ant genus Thaumatomyrmex Mayr (Hymenoptera: Formicidae). Pp. 35-42 in: Trager, J. C. (ed.) 1988. Advances in myrmecology. Leiden: E. J. Brill, xxvii + 551 pp.
  • Longino J. T. L., and M. G. Branstetter. 2018. The truncated bell: an enigmatic but pervasive elevational diversity pattern in Middle American ants. Ecography 41: 1-12.
  • Longino J. T., and R. K. Colwell. 2011. Density compensation, species composition, and richness of ants on a neotropical elevational gradient. Ecosphere 2(3): 16pp.
  • Longino J. et al. ADMAC project. Accessed on March 24th 2017 at
  • Lozano-Zambrano F. H., E. Jimenez, T. M. Arias-Penna, A. M. Arcila, J. Rodriguez, and D. P. Ramirez. 2008. Biogeografía de las hormigas cazadoras de Colombia. Pp. 349-406. in: Jiménez, E.; Fernández, F.; Arias, T.M.; Lozano-Zambrano, F. H. (eds.) 2008. Sistemática, biogeografía y conservación de las hormigas cazadoras de Colombia. Bogotá: Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, xiv + 609 pp.
  • Mirmecofauna de la reserva ecologica de San Felipe Bacalar
  • Philpott, S.M., P. Bichier, R. Rice, and R. Greenberg. 2007. Field testing ecological and economic benefits of coffee certification programs. Conservation Biology 21: 975-985.
  • Ramón G., A. Barragán, and D. A. Donoso. 2013. Can clay banks increase the local ant species richness of a montane forest? In press: Métodos en Ecología y Sistemática 8: 37 – 53.
  • Rodriguez E. R., and J. E. Lattke. 2012. Diversidad de hormigas en un gradiente altitudinal de la cordillera de la Costa, Venezuela. Boletín de la Sociedad Entomológica Aragonesa (S.E.A.) 50: 295?304.
  • Scott-Santos, C.P., F.A. Esteves, C.R.F. Brandao. 2008. Catalogue of "Poneromorph" ant type specimens (Hymenoptera, Formicidae) deposited in the Museu de Zoologia da Universidade de Sao Paulo, Brazil. Papeis Avulsos de Zoologia 48(11):75-88.
  • 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
  • Smith M. R. 1944. Ants of the genus Thaumatomyrmex Mayr with the description of a new Panamanian species (Hymenoptera: Formicidae). Proceedings of the Entomological Society of Washington 46: 97-99.
  • Weber N. A. 1939. New ants of rare genera and a new genus of ponerine ants. Ann. Entomol. Soc. Am. 32: 91-104.
  • Weber N. A. 1942. The genus Thaumatomyrmex Mayr with description of a Venezuelan species (Hym.: Formicidae). Bol. Entomol. Venez. 1: 65-71.