Brachymyrmex bonariensis

Nothing is known about the biology of .

Identification
Ortiz-Sepulveda et al. (2019) - Brachymyrmex bonariensis resembles Brachymyrmex admotus because they both have scapes that surpass the posterior margin of the head, a pair of simple erect hairs between the dorsal methathoracic spiracles, a wide metanotal groove, and a gaster with scarce pubescence. However, in B. bonariensis, the head and mesosoma are light brownish in color, and the gaster is darker, whereas the body of B. admotus is uniformly colored. The scapes of B. bonariensis are shorter than those of B. admotus and surpass the posterior margin of the head with a length approximately equal to the maximal diameter of the eyes. The metathoracic spiracles of B. bonariensis are furthermore positioned more laterally and are not protruding. Like B. admotus, B. bonariensis could be confused with Brachymyrmex cavernicola because this latter species also has a pair of erect hairs between the methathoracic spiracles, however in B. cavernicola these hairs are very thick, and they are darker in color than the body.

Brachymyrmex bonariensis was first described by Santschi (1933) as a variety of B. constrictus. These two species differ by a mesonotum in B. bonariensis that does not bulge dorsally above the pronotum in lateral view whereas that of B. constrictus does and B. constrictus does not have erect hairs between the metathoracic spiracles and moreover it has a uniformly dark brownish body.

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina.

Nomenclature

 * . Brachymyrmex constrictus st. bonariensis Santschi, 1933e: 122, figs. 20, 21 (w.) ARGENTINA (Buenos Aires).
 * Subspecies of constrictus: Kempf, 1972a: 38; Bolton, 1995b: 81.
 * Status as species: Ortiz-Sepúlveda, et al. 2019: 474 (redescription).

Worker
Ortiz-Sepulveda et al. (2019) - Lectotype HL1 0.53; HL2 0.36; HL3 0.15; HW 0.48; SL 0.49; EL 0.13; WL 0.50; PnL 0.14; PnW 0.31; ML 0.12; MW 0.20; Indices CI 90.00; SL1102.78; SL2 134.55; OI1 22.78; OI2 27.50. Paralectotypes HL1 0.53; HL2 0.35; HL3 0.15; HW 0.50; SL 0.50; EL 0.13; WL 0.53; PnL 0.18; PnW 0.34; ML 0.11; MW 0.18; Indices CI 92.59; SL1 101.33; SL2 143.40; OI1 26.67; OI2 27.16.

Head. Slightly longer than wide in full face view; posterior cephalic margin slightly concave. Dorsum of head with scattered, appressed hairs and usually two rows of erect hairs. Clypeus with a rounded anterior margin and five long, erect hairs of which a single, usually conspicuous hair is near the anterior margin, two hairs are in mediolateral position, and two more near the toruli; other hairs on the clypeus are markedly shorter and appressed or decumbent. Toruli surpassing the posterior clypeal margin in oblique anterodorsal view. The scapes surpass the posterior margin of the head by a length approximately equal to the maximal diameter of the eyes. Ocelli appear to be present but are inconspicuous. Eyes are positioned on the cephalic midline and have 8–9 ommatidia along their maximal diameter.

Mesosoma. With two erect hairs on the pronotum and two on the mesonotum. In lateral view, the mesonotum is somewhat inflated, but it does not bulge dorsally above the pronotum. Metanotal groove wider than the diameter of the metathoracic spiracles. Metathoracic spiracles in dorsolateral position, not protruding, but touching the propodeal suture. Between the metathoracic spiracles two thin erect hairs are present, but they are shorter than those on the pronotum and mesonotum. Dorsum of the propodeum flat and ~ 1/3th of the length of the propodeal slope. Propodeal spiracles circular, positioned on the posterior propodeal margin slightly posterior of the middle of the propodeal slope. Legs with appressed and scattered hairs. Petiole short and inclined forward.

Gaster. With scattered pubescence, and scattered suberect hairs, mainly along the edges of the segments.

Color and sculpture. Body overall smooth and shiny, except for the slightly imbricate sculpture on the dorsum of the mesosoma in some specimens. Head and mesosoma light brown, gaster darker in color.

Type Material
Ortiz-Sepulveda et al. (2019) - Lectotype worker (: USNMENT00757706) and paralectotype worker (NHMB: USNMENT00757705; here designated): two workers [examined]. ARGENTINA: Buenos Aires: Buenos Aires, 08 Mar. 1803, C. Bruch.

References based on Global Ant Biodiversity Informatics

 * Cuezzo, F. 1998. Formicidae. Chapter 42 in Morrone J.J., and S. Coscaron (dirs) Biodiversidad de artropodos argentinos: una perspectiva biotaxonomica Ediciones Sur, La Plata. Pages 452-462.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Ortiz-Sepuvelda C. M., B. Van Bocxlaer, A. D. Meneses, and F. Fernandez. 2019. Molecular and morphological recognition of species boundaries in the neglected ant genus Brachymyrmex (Hymenoptera: Formicidae): toward a taxonomic revision. Organisms Diversity & Evolution https://doi.org/10.1007/s13127-019-00406-2