Brachymyrmex australis

Some specimens have been found under stones and among leaf litter. The type material of the synonomized Brachymyrmex longicornis was collected from orchids.

Identification
Ortiz-Sepulveda et al. (2019) - Brachymyrmex australis is very similar in morphology to Brachymyrmex aphidicola, Brachymyrmex minutus, and Brachymyrmex termitophilus, because all these species have a mesonotum that does not bulge dorsally above the pronotum in lateral view, their bodies are smooth, shiny and yellowish, and their eyes are positioned on the cephalic midline. However, Brachymyrmex australis differs from B. aphidicola by somewhat shorter scapes, although they still reach to the posterior margin of the head or surpass it by a length equal to or smaller than the maximal diameter of the eye; it differs from B. minutus by having a well-marked mesometanotal suture and two erect hairs on the pronotum and two on the mesonotum; finally, it has scattered pubescence on the gaster whereas that of B. termitophilus is dense.

Distribution based on Regional Taxon Lists
Malagasy Region: Mauritius. Neotropical Region: Argentina, Bahamas, Brazil , Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, French Guiana, Guatemala, Guyana, Mexico, Paraguay, Peru, Uruguay.

Nomenclature

 * . Brachymyrmex minutus r. australis Forel, 1901d: 302 (w.) BRAZIL (Rio Grande do Sul).
 * Status as species: Santschi, 1922d: 260; Santschi, 1923b: 662; Emery, 1925b: 41; Borgmeier, 1927c: 140; Kempf, 1972a: 38; Bolton, 1995b: 81; Fernández & Ortiz-Sepúlveda, 2019: 728; Ortiz-Sepúlveda, et al. 2019: 468 (redescription).
 * Senior synonym of curta: Ortiz-Sepúlveda, et al. 2019: 468.
 * Senior synonym of longicornis: Ortiz-Sepúlveda, et al. 2019: 468.
 * curta. Brachymyrmex australis var. curta Santschi, 1922d: 260 (q.m.) ARGENTINA (Córdoba), URUGUAY.
 * [Also described as new by Santschi, 1923b: 663 (w.).]
 * Subspecies of australis: Emery, 1925b: 41; Santschi, 1931e: 281; Kempf, 1972a: 38; Zolessi, et al. 1988: 6; Bolton, 1995b: 82.
 * Junior synonym of australis: Ortiz-Sepúlveda, et al. 2019: 468.
 * longicornis. Brachymyrmex longicornis Forel, 1907e: 9 (w.) BRAZIL (Rio Grande do Sul).
 * Forel, 1912i: 62 (q.).
 * Status as species: Forel, 1908b: 64; Forel, 1912i: 62; Forel, 1913l: 245; Forel, 1914d: 288; Bruch, 1914: 227; Forel, 1915c: 361; Bruch, 1916: 348; Santschi, 1923b: 667; Emery, 1925b: 42; Borgmeier, 1927c: 142; Kusnezov, 1953b: 339; Kempf, 1972a: 40; Bolton, 1995b: 82.
 * Junior synonym of australis: Ortiz-Sepúlveda, et al. 2019: 468.

Worker
Ortiz-Sepulveda et al. (2019) - Lectotype worker HL1 0.37; HL2 0.27; HL3 0.10; HW 0.29; SL 0.29; EL 0.10; WL 0.35; PnL n.a.; PnW 0.23; ML 0.08; MW 0.17; Indices CI 78.95; SI1 100.00; SI2 107.14; OI1 33.33; OI2 26.31. Additional material (n = 13). HL1 0.32–0.54; HL2 0.21–0.38; HL3 0.08–0.15; HW 0.29–0.53; SL 0.26–0.48; EL 0.08–0.14; WL 0.29–0.55; PnL 0.08–0.20; PnW 0.21–0.32; ML 0.06–0.11; MW 0.14– 0.20; Indices CI 82.61–97.09; SI1 89.09–104.54; SI2 114.29– 135.29; OI1 15.38–30.91; OI2 19.35–28.33.

Head. Slightly longer than wide in full face view; posterior cephalic margin slightly concave. Dorsum of the head with scattered 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 extend beyond the posterior margin of the head by a length equal to or smaller than the maximal diameter of the eye; they typically have appressed, sometimes decumbent, but never erect hairs. Three inconspicuous ocelli. Eyes on the cephalic midline, with 7–14 ommatidia along their maximal diameter.

Mesosoma. Typically with two erect hairs on the pronotum and two on the mesonotum. The mesonotum is not inflated and it does not bulge dorsally above the pronotum in lateral view. Metanotal groove absent or shallow and narrower than the diameter of the metathoracic spiracles. Metathoracic spiracles in dorsolateral position, not protruding, and usually touching both the mesometanotal and propodeal sutures. Dorsum of the propodeum flat or weakly convex and ~ 1/3th of the length of the propodeal slope. Propodeal spiracles circular, positioned ventrally of 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 long suberect hairs.

Color and sculpture. Body smooth and shiny, uniform yellowish in color

Type Material
Ortiz-Sepulveda et al. (2019) - Lectotype worker (: USNMENT00757156) and paralectotype worker (MHNG: USNMENT00758102; here designated): two workers [examined]. BRAZIL: Rio Grande do Sul: Pelotas.

References based on Global Ant Biodiversity Informatics

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