Octostruma onorei

Nothing is known about the biology of .

Identification
Shares with Octostruma iheringi the structure of the propodeal spines, the longitudinal trough on the mesosomal dorsum, and the general habitus (based on the description and the figures in the original publication). It differs in having erect setae on the mesosoma and first gastral tergite, and the first gastral tergite is smooth and shining. (Longino 2013)

A Basiceros species belonging to the petiolatum-group as defined by Brown & Kempf (1960) (in Octostruma) and differing from all species of this group, inca, jheringi, stenoscapum, petiolatum and wheeleri (Brown & Kempf, 1960; Palacio, 1997), by the following combination of characters: occipital margin with a row of four clavate hairs, each upper scrobe margin with one clavate hair, pronotum and mesonotum with a pair of clavate hairs each, gaster with 4 rows of erect, clavate hairs (2,2,2,4), sides of the basal face of the propodeum strongly marginate, and propodeum, pleurae and gaster largely smooth, sub-opaque to shining. B. onorei differs from the 5 known species of the petiolatum-group of "Octostruma" as defined by Brown & Kempf (1960) by the combination of characters listed in the diagnosis. B. onorei shares with iheringi the head dorsum with irregular rugosities but differs from iheringi mainly by the presence of standing hairs on the mesosoma and gaster. B. onorei shares with petiolatum the mesosoma and gaster superficially smooth but differs from it mainly by having 6 standing hairs instead of 16 on the head dorsum and by the head weakly instead of broadly convex. (Baroni Urbani & De Andrade 2007)

Key to Octostruma workers

Distribution based on Regional Taxon Lists
Neotropical Region: Ecuador.

Nomenclature

 *  onorei. Basiceros onorei Baroni Urbani & De Andrade, 2007: 133, fig. 47 (w.) ECUADOR. Combination in Octostruma (unpublished).

Longino (2013) - This species is known only from the holotype. From the description, it appears to be a version of Octostruma iheringi.

Worker
Head dorsum weakly convex in full dorsal view. Posterolateral sides of the head with the two anterior thirds diverging posteriorly into a round angle and the posterior third gently converging into a weakly concave vertexal margin. Frontal lobes weakly expanded and convex. Antennal fossae ventrally with a marked carina visible in full-face view, straight, covering the lower margin of the scrobes and ending below the eye. Eyes small, with 4 ommatidia in the longest row, placed on the upper margin of the antennal scrobes. With head in profile the scrobe very distinct, with the upper margin behind the eye broad, lamellaceous, semitransparent and the lower one strongly carinate. Anterior clypeal border medially with a broad concavity. Scapes slightly compressed dorsoventrally, with strong subbasal bend. Antennae with eight joints. Apical funicular joint slightly longer than the rest of the funiculus. Mandibles triangular, with a series of 5 teeth and two irregular denticles before the subround apex.

Mesosoma anteriorly convex and posteriorly sloping in profile. Dorsum of the mesosoma medially with a broad, superficial, longitudinal sulcus spacing from the pronotum to the mesonotum. Propodeal suture superficially impressed. Posterior half of the basal face of the propodeum gently concave. Sides of the basal face of the propodeum strongly marginate. Propodeal teeth large, lamellaceous, transparent, apically pointed and with broad base. Upper bases of propodeal teeth strongly marginate, connected each other and forming a clear carina dividing the basal and declivous faces. Lower base of propodeal teeth ending on the middle of the declivous face. Posterior half of the declivous propodeal face weakly marginate. Propodeal spiracle large and below the lower base of the propodeal tooth.

Petiole with a long neck and with the node high anteriorly and sloping posteriorly. Ventral surface of the petiolar neck anteriorly with a small lamellaceous tooth pointed forwards. Postpetiole almost flat in side view; in dorsal view the anterior and posterior borders well marked by a thicker and anteriorly semitransparent carina.

Gaster oval. Base of the first gastral tergite clearly marginate. Base of the first gastral sternite superficially marginate.

Sculpture. Head reticulate-punctuate and with thin, irregular longitudinal rugosities. Pronotum and mesonotum irregularly reticulate and very superficially punctuate, the reticulation less marked on the posterior half of the mesonotum. Propodeum and pleurae smooth and shining, in addition the pleurae with a few minute punctures. Gaster smooth and shining, in addition the posterior border of the first gastral tergite, the anterior and posterior borders of the first gastral sternite and all remaining tergites and sternites with well impressed, large punctures.

Pilosity. Body with appressed, short, thin, decumbent hairs, very rare on the dorsum of the propodeum and pleurae. Posterior margin of the head dorsum with a row of four clavate erect hairs. Upper antennal scrobes with one clavate erect hair each. Pronotum, mesonotum and posterior half of the petiole and postpetiole with a pair of clavate, erect hairs each. First gastral tergite with four rows of clavate erect hairs, the first up to the third rows with two clavate hairs and the fourth row with four hairs close to the posterior border. Remaining gastral tergites with four clavate hairs, thinner than on the first tergite. First gastral sternite medially with erect, truncate or weakly clavate hairs; posterior half of the first gastral sternite and remaining gastral sternites with clavate hairs much thinner than on the tergites. Apex of the tibiae with a few clavate hairs.

Colour. Dark brown with slightly lighter antennae and legs.

Measurements (in mm) and indices: TL 2.84; HL 0.67; HW 0.74; SL 0.45; ML 0.22; EL 0.06; WL 0.76; CI 110.4.

Type Material
Holotype worker (unique) from Ecuador labelled: Banos de Agua Santa, Provo Tungurahua, 01 °24'S 78°25'W, 1860 m, sendero Bella Vista, leaf-litter, 26.VIII.2004, C. Baroni Urbani & M. L. de Andrade.

Etymology
This species is named after Prof. Dr Giovanni Onore who facilitated in multiple ways our Dacetini field work in Ecuador.