Brachymyrmex bruchi

Known from mesic forests, specimens have been taken from a treefall, downed branch, and sand.

Identification
Ortiz-Sepulveda et al. (2019) - Brownish body color, scapes that surpass the posterior cephalic margin by a length that approximately equals the maximal diameter of the eye, the metanotal groove is lacking or narrow, and scattered pubescence on the gaster.

Brachymyrmex bruchi is morphologically most similar to Brachymyrmex patagonicus and Brachymyrmex oculatus because these species have scapes that surpass the posterior margin of the head, typically two erect hairs on the mesonotum, their metanotal groove is either absent or narrower than the diameter of the metathoracic spiracles, their mesonotum does not bulge dorsally above the pronotum in lateral view, their gaster has several scattered long erect hairs and sparse pubescence, and they have brownish bodies. However, B. bruchi differs from B. patagonicus by having a larger body size, abundant suberect hairs on the dorsum of the pronotum, and scapes that surpass the posterior margin of the head by a length approximately equal to the maximal diameter of the eye. It differs from B. oculatus by having smaller eyes with less than 14 ommatidia along the maximal diameter, which approximately equal only a quarter of the length of the head (HL1).

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Argentina, Bolivia, Brazil, Chile, Colombia, Dominican Republic, Ecuador, Guatemala, Paraguay, Uruguay.

Nomenclature

 * . Brachymyrmex bruchi Forel, 1912i: 64 (w.m.) ARGENTINA (Catamarca).
 * Santschi, 1929d: 309 (q.).
 * Status as species: Bruch, 1914: 227; Santschi, 1916e: 395; Bruch, 1917d: 432; Santschi, 1923b: 660; Emery, 1925b: 41; Santschi, 1929d: 309; Kusnezov, 1953b: 339; Kempf, 1972a: 38; Bolton, 1995b: 82; Quirán, et al. 2004: 279 (redescription) ; Fernández & Ortiz-Sepúlveda, 2019: 728; Ortiz-Sepúlveda, et al. 2019: 476 (redescription).
 * Senior synonym of andina: Ortiz-Sepúlveda, et al. 2019: 476.
 * Senior synonym of nitida: Ortiz-Sepúlveda, et al. 2019: 476.
 * Senior synonym of rufipes: Quirán, et al. 2004: 279; Ortiz-Sepúlveda, et al. 2019: 476.
 * andina. Brachymyrmex levis var. andina Santschi, 1923b: 659 (w.) ARGENTINA (Jujuy).
 * Subspecies of laevis: Emery, 1925b: 42; Kempf, 1972a: 40; Bolton, 1995b: 81.
 * Junior synonym of bruchi: Ortiz-Sepúlveda, et al. 2019: 476.
 * nitida. Brachymyrmex giardi var. nitida Santschi, 1922d: 261 (w.) CHILE.
 * Subspecies of giardi: Emery, 1925b: 42; Goetsch & Menozzi, 1935: 100; Kempf, 1970a: 31; Kempf, 1972a: 39.
 * Junior synonym of giardi: Snelling & Hunt, 1976: 114; Brandão, 1991: 332; Bolton, 1995b: 82.
 * Junior synonym of bruchi: Ortiz-Sepúlveda, et al. 2019: 476.
 * rufipes. Brachymyrmex bruchi var. rufipes Forel, 1912i: 65 (w.) ARGENTINA (Catamarca).
 * Subspecies of bruchi: Bruch, 1914: 227; Santschi, 1916b: 512; Santschi, 1923b: 660; Emery, 1925b: 41; Santschi, 1933e: 122; Kempf, 1972a: 38; Bolton, 1995b: 82.
 * Junior synonym of bruchi: Quirán, et al. 2004: 279; Ortiz-Sepúlveda, et al. 2019: 476.

Worker
Ortiz-Sepulveda et al. (2019) - Lectotype and paralectotypes (n = 4). HL1 0.58–0.64; HL2 0.41–0.45; HL3 0.14–0.18; HW 0.57– 0.60; SL 0.55–0.62; EL 0.16–0.18; WL 0.64–0.78; PnL 0.20– 0.25; PnW 0.39–0.45; ML 0.18–0.21; MW 0.27–0.31; Indices CI 90.63–100.00; SI1 93.33–103.45; SI2 130.43–142.86; OI1 26.67–31.03; OI2 21.88–28.13. Additional material (n = 25). HL1 0.41–0.61; HL2 0.29–0.42; HL3 0.09–0.16; HW 0.37–0.60; SL 0.31–0.59; EL 0.10–0.20; WL 0.40–0.72; PnL 0.10–0.20; PnW 0.25–0.44; ML 0.09–0.20; MW 0.16– 0.29; Indices CI 70.98–96.97; SI1 78.13–136.36; SI2 106.67– 156.76; OI1 23.91–45.45; OI2 19.23–28.00.

Head. Slightly longer than wide in full face view; posterior cephalic margin slightly concave. Dorsum of the head with sparse and appressed 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 cephalic margin with a length that approximately equals the maximal diameter of the eye; they typically have appressed and decumbent hairs. Three inconspicuous ocelli present. Eyes are positioned on the cephalic midline and have 8–13 ommatidia along their maximal diameter.

Mesosoma. Typically with two erect hairs on the pronotum and two on the mesonotum, sometimes with additional suberect hairs, mainly on the pronotum. The mesonotum is not inflated and does not bulge dorsally above the pronotum in lateral view. Metanotal groove absent or narrower than the diameter of the metathoracic spiracles. Metathoracic spiracles in dorsolateral position, not protruding, but touching the propodeal suture. Dorsum of the propodeum slightly convex and shorter than the posterior slope. Propodeal spiracles circular, positioned on the posterior propodeal margin at the middle of the propodeal slope. Legs with appressed and scattered hairs. Petiole short and inclined forward.

Gaster. With sparse pubescence and several scattered long erect hairs.

Color and sculpture. Body overall smooth and shiny, except for the sometimes slightly imbricate sculpture on the dorsum of the mesosoma; typically brownish.

Type Material
Ortiz-Sepulveda et al. (2019) - Lectotype worker (: USNMENT00757159), and paralectotype workers, males (MHNG: USNMENT007157–007159, 00758104, 00758149–00758181; here designated): 21 workers, three males [examined]. ARGENTINA: Catamarca: Aconquija, Filo blanco, 4300 m, Bruch. Santschi (1929: 309) (q.).

The here designated lectotype is the specimen at the top of pin MHNG: USNMENT00757159, and the ants below are paralectotypes.

References based on Global Ant Biodiversity Informatics

 * Bruch C. 1914. Catálogo sistemático de los formícidos argentinos. Revista del Museo de La Plata 19: 211-234.
 * 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.
 * Forel A. 1912. Formicides néotropiques. Part VI. 5me sous-famille Camponotinae Forel. Mémoires de la Société Entomologique de Belgique. 20: 59-92.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Kusnezov N. 1978. Hormigas argentinas: clave para su identificación. Miscelánea. Instituto Miguel Lillo 61:1-147 + 28 pl.
 * 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
 * Quiran E. M., J. J. Martínez, and A. O. Bachmann. 2004. The Neotropical genus Brachymyrmex Mayr, 1868 (Hymenoptera: Formicidae) in Argentina. Redescription of the type species, B. patagonicus Mayr,1868; B. bruchi Forel, 1912 and B. oculatus Santschi, 1919. Acta Zool. Mex. Nueva Série 20: 273-285.
 * Santschi F. 1916. Descriptions de fourmis nouvelles d'Afrique et d'Amérique. Annales de la Société Entomologique de France 84: 497-513.
 * Santschi F. 1923. Revue des fourmis du genre Brachymyrmex Mayr. Anales del Museo Nacional de Historia Natural de Buenos Aires 31: 650-678.
 * Santschi F. 1933. Fourmis de la République Argentine en particulier du territoire de Misiones. Anales de la Sociedad Cientifica Argentina. 116: 105-124.