Mycetomoellerius iheringi

Entry number 2007 in Goncalves’s notebook says “ninho subterraneo com olheiro fino na areia,” that is, subterranean nest in sand with slim opening.

Identification
A member of the Iheringi species group. Mayhe-Nunes and Brandão (2005) - The exclusive character of M. iheringi is the finely striated discal area of the mandibles; however, Emery (1888) reported that some specimens lack such striation. This species falls within Mycetomoellerius kempfi into the same dichotomy in the identification key. Although both share very similar frontal lobes, M. iheringi first (anterior) pair of mesonotal projections are shorter, whereas the second (posterior) ones are longer (sometimes absent in M. kempfi). Two others striking differences are the lack of flexous pilosity and the shape of lobes of antennal scapes in M. iheringi (see discussion for M. kempfi).

Except by the coloration and size of the katepisternum projection we did not observe any other significant variation in the studied specimens.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil.

Nomenclature

 *  iheringi. Atta (Acromyrmex) iheringi Emery, 1888c: 359 (w.q.m.) BRAZIL.
 * Combination in Atta (Trachymyrmex): Forel, 1893e: 601.
 * Combination in Acromyrmex (Trachymyrmex): Forel, 1914d: 282.
 * Combination in Trachymyrmex: Gallardo, 1916b: 242.
 * Combination in Mycetomoellerius: Solomon et al., 2019: 948.
 * [Name sometimes misspelled as jheringi, for example by Kempf, 1972a: 253.]
 * See also: Mayhé-Nunes & Brandão, 2005: 286.

Worker
Mayhe-Nunes and Brandão (2005) - TL 3.5-4 .2; HL 1.05-1.09; HW 0.92-1.00; IFW 0.62-0.69; ScL 0.75-0.85; TrL 1.34- 1.54; HfL 1.15-1.25. Uniformly dark reddish brown to dark brown. Integument fine and shagreened, opaque. Body and appendages clothed with moderately long and oblique to decumbent hairs; mixed with strongly curved short hairs on some parts of occiput, alitrunk, postpetiole and gaster.

Head in full face view as long as broad (CI 100). Mandible fine and completely striate on its dorsal surface, which bears the apical and sub-apical teeth, and 5 regularly developed teeth. Frontal lobe subtriangular, moderately expanded laterad (FLI 65); anterior border concave; posterior border rather straight. Frontal carina diverging caudad, reaching the apex of scrobe. Front and vertex with weak longitudinal rugulae. Posterior third of antennal scrobe clearly delimited by the frontal carina and weakly marked by the extension of the preocular ones. Supraocular projection formed by a group of small tubercles. Occiptal corner rounded in full-face view, surmounted by some stout piligerous tubercles. Occiput slightly notched in the middle. Occipital tooth developed as a stout and tubercle-like projection, rather microtuberculated. Inferior occipital corner emarginated, not forming carina. Eye convex, no more than 12 facets in a row across the greatest diameter. Antennal scape slightly surpassing the occipital margin, when laid back over head as much as possible; basal lobe perpendicularly enlarged, its outer projection bigger than the internal ones, outwards directed when the scape is lodged in the scrobe; anterior surface surmounted by small tubercles and ridges.

Alitrunk. Pronotum with indistinct humeral angle; antero-inferior corner rather angulated; lateral spine long; median projections as a small bifid tubercle. First and second pair of mesonotal projections shorter than pronotal lateral ones, forming a blunt short ridge and teeth-like tubercle, respectively; third pair very small. Mesopleura covered with hairs; superior border of katepisternum vestigially armed with a small and blunt teeth-like projection. Alitrunk weakly constricted dorso-laterally at the shallowly impressed metanotal groove. Basal face of propodeum narrow, laterally delimited by a small dentate ridge; propodeal spines similar to lateral pronotal ones.

Waist and gaster. Petiole shortly pedunculated, the node proper as long as broad, with one pair of small teeth; subpetiolar process vestigial. Poslpetiole slightly broader than long, shallowly excavated above; postero-dorsal border convex; postero-lateral corners without 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, female and male; Brazil. Rio Grande do Sul: Sao Lourenco.

Two syntype workers labeled “iheringi (type) XXI.V.d.3416 Rio Grande do Sul. Ihering col” in ; not examined Dietz personnal communication).

We have found in CECL a pin with one worker labeled as: Rio Gr. do SuI, v. Iheling, 2728, Em. det., Trachymyrmex iheringi Em. det. Borgmeier. Except by the collection number and the identification label, surely written by Borgmeier, the other informations match with Dietz’s annotations taken in the Basel Museum, where he found the syntypes of the species. Kempf (1972) cleared up one information absent in the label of type material: the type locality of the species is Sao Lourenco, at southern Rio Grande do Sul State.