Brachymyrmex attenuatus

Nothing is known about the biology of .

Identification
Ortiz-Sepulveda et al. (2019) - Brachymyrmex attenuatus morphologically resembles Brachymyrmex degener, because both have long scapes that extend beyond the posterior margin of the head, they have faint sculpture on the mesosomal dorsum, and dorsally positioned, slightly protruding metathoracic spiracles. Brachymyrmex attenuatus differs from Brachymyrmex degener, however, by having a gaster with dense pubescence.

This species was described by Santschi (1929) as a subspecies of Brachymyrmex luederwaldti that has a smaller body size in comparison with B. luederwaldti. Additionally, B. attenuatus has weaker sculpture, a shinier body, especially on pronotum, a more concave posterior cephalic border, smaller eyes and a more convex mesonotum than B. luederwaldti. All these characteristics are somewhat subjective, because they represent differences in intensity rather than state and as such it is difficult to determine clear boundaries. A more marked difference is the presence of pubescence on the gaster, which is clearly present in B. attenuatus, but absent in B. luederwaldti.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil.

Nomenclature

 * . Brachymyrmex luederwaldti st. attenuatus Santschi, 1929d: 310 (w.) BRAZIL (Santa Catarina).
 * Subspecies of luederwaldti: Kempf, 1972a: 40; Bolton, 1995b: 81.
 * Status as species: Ortiz-Sepúlveda, et al. 2019: 567 (redescription).

Worker
Ortiz-Sepulveda et al. (2019) - Lectotype worker HL1 0.47; HL2 0.28; HL3 0.11; HW 0.43; SL n.a.; EL 0.12; WL 0.52; PnL 0.09; PnW 0.31; ML 0.12; MW 0.21; Indices CI 90.74; SI1 n.a; SI2 n.a; OI1 28.57; OI2 23.15. Paralectotype worker HL1 0.43; HL2 0.31; HL3 0.11; HW 0.39; SL 0.45; EL 0.13; WL 0.46; PnL 0.14; PnW 0.29; ML 0.11; MW 0.15; Indices CI 91.84; SI1 113.33; SI2 145.71; OI1 33.33; OI2 25.51.

Head. Slightly longer than wide in full face view; posterior cephalic margin slightly concave. Dorsum of 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 substantially shorter and appressed or decumbent. Toruli surpassing the posterior clypeal margin in oblique anterodorsal view. The scapes extend beyond the posterior cephalic margin by a length approximately equal to the maximum diameter of the eye (and not more than 1.5× this diameter), and have decumbent hairs. A single central ocellus seems to be present but is inconspicuous. Eyes are positioned on the cephalic midline and have 7–9 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 pronotum. In lateral view, the mesonotum is inflated, but it does not bulge dorsally above the pronotum. Metanotal groove deep and wider than the diameter of the metathoracic spiracles. Metathoracic spiracles fully dorsal in position, slightly protruding and not touching the mesometanotal or propodeal sutures. Dorsum of propodeum slightly convex and shorter than the propodeal slope. Propodeal spiracles circular, positioned ventrally of the posterior propodeal margin, and slightly posteriorly of the middle of the propodeal slope. Legs with appressed and scattered hairs. Petiole short and inclined forward.

Gaster. With appressed dense pubescence and several scattered long erect hairs.

Color and sculpture. Body overall smooth and shiny, with faint sculpture on mesosomal dorsum. Body uniformly light or dark brownish, but the legs and antennae are yellowish.

Type Material
Ortiz-Sepulveda et al. (2019) - Lectotype worker (: USNMENT00757177) and Paralectotype worker (NHMB: USNMENT00757177; here designated) two workers [examined]. BRAZIL: Santa Catarina: Blumenau.

We designate the lectotype as the specimen closest to the pin (USNMENT00757177); the paralectotype has lighter brownish color in comparison with the lectotype.

References based on Global Ant Biodiversity Informatics

 * 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
 * Rosa da Silva R. 1999. Formigas (Hymenoptera: Formicidae) do oeste de Santa Catarina: historico das coletas e lista atualizada das especies do Estado de Santa Catarina. Biotemas 12(2): 75-100.
 * Santschi F. 1929. Nouvelles fourmis de la République Argentine et du Brésil. Anales de la Sociedad Cientifica Argentina. 107: 273-316.
 * Ulyssea M. A., C. E. Cereto, F. B. Rosumek, R. R. Silva, and B. C. Lopes. 2011. Updated list of ant species (Hymenoptera, Formicidae) recorded in Santa Catarina State, southern Brazil, with a discussion of research advances and priorities. Revista Brasileira de Entomologia 55(4): 603–611.
 * Ulyssea M.A., C. E. Cereto, F. B. Rosumek, R. R. Silva, and B. C. Lopes. 2011. Updated list of ant species (Hymenoptera, Formicidae) recorded in Santa Catarina State, southern Brazil, with a discussion of research advances and priorities. Revista Brasileira de Entomologia 55(4): 603-611.