Mycetomoellerius tucumanus

Identification
Mayhe-Nunes and Brandão (2005) - This species falls into same dichotomy with Trachymyrmex holmgreni in the identification key. Besides differences pointed out in the discussion, T. tucumanus has a distinct shape of the antennal scapes lobes, without marked tip.

Except for the slight differences observed in the synonymized varieties, we did not observe any significant variation in the other studied specimens.

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

Nomenclature

 *  tucumanus. Acromyrmex (Trachymyrmex) iheringi var. tucumana Forel, 1914d: 282 (w.) ARGENTINA. Bruch, 1921: 202 (q.). Combination in Trachymyrmex: Gallardo, 1916d: 325. Raised to species: Santschi, 1925e: 164. Senior synonym of cordovanus, fracticornis, weiseri: Mayhé-Nunes & Brandão, 2005: 299.
 * cordovanus. Acromyrmex (Trachymyrmex) iheringi var. cordovana Bruch, 1921: 202 (w.) ARGENTINA. Combination in Trachymyrmex: Kempf, 1972a: 254. Subspecies of tucumanus: Santschi, 1922b: 358. Junior synonym of tucumanus: Mayhé-Nunes & Brandão, 2005: 299.
 * fracticornis. Trachymyrmex tucumana var. fracticornis Santschi, 1925e: 164 (w.) ARGENTINA. Junior synonym of tucumanus: Mayhé-Nunes & Brandão, 2005: 299.
 * weiseri. Trachymyrmex tucumana var. weiseri Santschi, 1925e: 164 (w.) ARGENTINA. Junior synonym of tucumanus: Mayhé-Nunes & Brandão, 2005: 299.

Worker
Mayhe-Nunes and Brandão (2005) - TL 3.7-4.2; HL 1.14-1.26; HW 1.02-1.18; IFW 0.62-0.68; ScL 0.85-0.95; TrL 1.40-1.51; HfL 1.26-1.37. Ferruginous to yellowish brown, some specimens with darker gaster. Integument fine and indistinctly shagreened, opaque. Hairs moderately scarce on the body, short and erect or curved on appendages; hook-like mixed with oblique to decumbent hairs on other parts of body.

Head in full view as long as broad (CI 100). Mandible smooth and shining except laterally on base where it is finely transversely striate, and near the masticatory margin, which bears the apical and 6 regularly developed teeth. Frontal lobe sub-triangular, moderately expanded laterad (FLI 58), backwards directed and laterally subdentate; anterior and posterior borders weakly concave. Frontal carina diverging caudad, reaching the apex of scrobe. Front and vertex with small isolated piligerous tubercles. Posterior third of antennal scrobe clearly delimited by the frontal carina but weakly marked by the extension of the preocular ones. Supraocular proection formed by a group of small tubercles. Occiput notched in the middle. Occipital tooth developed as a stout spine-like projection rather microtuberculated. Inferior occipital corner indistinctly emarginated with weak carina. Eye moderately convex, no more than 12 facets in a row across the greatest diameter. Antennal scape weakly surpassing the occipital corner when laid back over head as much as possible; basal lobe transversely enlarged, its lateral projections moderately expanded to both sides; anterior surface surmounted by small tubercles.

Alitrunk. Pronotum with a marked humeral angle; antero-inferior corner armed with a triangular and flattened spine-like projection; lateral spines long; median projections as two small microscopic spines. First pair of mesonotal projections, although a little stouter, similar to pronotal lateral ones; second and third projections represented by two parallel and longitudinal rows of small tubercles. Mesopleura without hairs; blunt to acute triangular projection on superior border of katepisternum (rarely inconspicuous).

Alitrunk weakly constricted dorso-laterally al the shallowly impressed metanotal groove. Basal face of propodeum narrow, laterally delimited by a row of small teeth, sometimes inconspicuous; propodeal spines longer and slender than promesonotal projections.

Waist and gaster. Petiole shortly pedunculate, the node proper as long as broad, with one pair of dorsal bifid teeth; subpetiolar process vestigial. Postpetiole slightly broader than long, shallowly excavated above; postero-dorsal border straight; postero-lateral corners wilhoul projections. Gaster opaque with minute piligerous tubercles more or less distributed in four irregular longitudinal series on tergum I.

Type Material
Mayhe-Nunes and Brandão (2005) - worker: Argentina, Tucuman, Concepcion.

T. tucumana (type) XXI.V.d.3419 Argentina, Tucuman, Chipton col in ; not examined (Dietz personal communication). Obs. Collecters name is Shipton in original description.

Syntype workers of the varieites T. tucumanus var. fracticornis and T. tucumanaus var. weiseri in ; examined.