Brachymyrmex admotus

This species makes nests in rotting wood [USNMENT00757763] and it has been collected from below rocks [USNMENT00759009].

Identification
Ortiz-Sepulveda et al. (2019) - Brachymyrmex admotus morphologically resembles Brachymyrmex bonariensis, because both species have long scapes, a conspicuous metanotal groove, a pair of thin erect hairs between the metathoracic spiracles, and a gaster with scarce pubescence. However, B. admotus is usually more uniform brownish in color, it has longer scapes (i.e., the scapes surpass the posterior cephalic margin with a length of approximately 1.5× the maximal diameter of the eye) with decumbent hairs, and its metathoracic spiracles are positioned more dorsally. Brachymyrmex admotus also resembles Brachymyrmex cavernicola in having a pair of erect hairs between the dorsal metathoracic spiracles, but these hairs are thinner in B. admotus and they are not darker in color than the body.

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Brazil, Paraguay.

Nomenclature

 * . Brachymyrmex admotus Mayr, 1887: 523 (w.q.) BRAZIL (Santa Catarina).
 * [Misspelled as admostus by Santschi, 1923b: 669, Santschi, 1933e: 122.]
 * Wheeler, G.C. & Wheeler, J. 1982: 178 (l.).
 * Status as species: Dalla Torre, 1893: 174; Forel, 1895b: 106; Pergande, 1896: 858 (redescription); Forel, 1899c: 123; Forel, 1907e: 9; Mann, 1916: 473; Santschi, 1923b: 669; Emery, 1925b: 41; Borgmeier, 1927c: 140; Santschi, 1933e: 122; Eidmann, 1936b: 92; Santschi, 1936d: 420; Kempf, 1972a: 38; Bolton, 1995b: 81; Quirán, 2005: 762 (redescription); Ortiz-Sepúlveda, et al. 2019: 460 (redescription).
 * Senior synonym of immunis: Ortiz-Sepúlveda, et al. 2019: 460.
 * immunis. Brachymyrmex longicornis var. immunis Forel, 1908c: 400 (w.q.m.) BRAZIL (São Paulo).
 * Subspecies of longicornis: Forel, 1909a: 263; Forel, 1911c: 308; Santschi, 1912e: 533; Bruch, 1915: 534; Luederwaldt, 1918: 48; Santschi, 1923b: 668; Emery, 1925b: 43; Borgmeier, 1927c: 142; Kempf, 1972a: 40; Zolessi, et al. 1988: 6; Bolton, 1995b: 82.
 * Junior synonym of admotus: Ortiz-Sepúlveda, et al. 2019: 461.

Worker
Ortiz-Sepulveda et al. (2019) - Lectotype HL1 0.51; HL2 0.35; HL3 0.12; HW 0.45; SL 0.49; EL 0.10; WL 0.49; PnL 0.14; PnW 0.31; ML 0.08; MW 0.18; Indices CI 88.46; SI1 108.70; SI2 138.89; OI1 21.74; OI2 23.08. Paralectotypes (n = 3). HL1 0.51– 0.57; HL2 0.35–0.39; HL3 0.12–0.14; HW 0.45–0.49; SL 0.55–0.59; EL 0.10; WL 0.53–0.59; PnL 0.14–0.21; PnW 0.31–0.35; ML 0.08–0.12; MW 0.18–0.21; Indices CI 86.21–92.59; SI1 112.00–121.74; SI2 140.00–155.60; OI1 20.00–21.74; OI2 23.08–25.93. Additional material (n = 16). HL1 0.46–0.57; HL2 0.30–0.43; HL3 011–0.14; HW 0.43–0.51; SL 0.47–0.57; EL 0.09–0.13; WL 0.46–0.61; PnL 0.16–0.22; PnW 0.29–0.34; ML 0.09–0.13; MW 0.17– 0.21; Indices CI 87.72–96.6; SI1 105.26–120.00; SI2 131.91– 155.88; OI1 18.87–26.92; OI2 21.43–28.30.

Head. Slightly longer than wide in full face view, with scattered appresed hairs except for two frontal rows of erect hairs; posterior cephalic border slightly concave. Dorsum of the head with sparse appressed pubescence. Clypeus with a rounded anterior margin and five long, erect hairs of which a single, usually conspicuous apical hair is near the anterior margin, two lateral hairs in medial 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. Scapes extend beyond the posterior cephalic margin by a length of ~ 1.5× the maximum eye diameter or more. The scapes typically have appressed, sometimes decumbent, but never erect hairs. A single central ocellus is present, but sometimes inconspicuous. Eyes are positioned on the cephalic midline and have 7–9 ommatidia along their maximal diameter.

Mesosoma. Usually with two erect hairs on the pronotum and two on the mesonotum; sometimes with additional suberect hairs on both. In lateral view, the mesonotum is not or slightly inflated and it does not or only slightly bulge dorsally above the pronotum. Metanotal groove deep and wider than the diameter of the metathoracic spiracles. Metathoracic spiracles fully dorsal and slightly protruding, they are closer to the propodeal than to the mesometanotal suture, but not touching any suture. Between the metathoracic spiracles two simple erect hairs are present, which 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 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 overall smooth and shiny, except for the sometimes slightly imbricate sculpture on the dorsum of the mesosoma; body typically uniform dark brown in color, although in some specimens the head and mesosoma may be light brownish and the gaster darker brown.

Type Material
Ortiz-Sepulveda et al. (2019) - Lectotype worker (: USNMENT00757197) and paralectotype workers, queen (NHMW:SNMENT00757196, 00757198-00757200; here designated): five workers, one queen [examined]. BRAZIL: Santa Catharina.

References based on Global Ant Biodiversity Informatics

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