Ochetomyrmex semipolitus

Specimen labels from the limited number of collections of Ochetomyrmex semipolitus state specimens were found in leaf litter and in rainforest, wet forest and cerrado habitat.

Identification
Fernández (2003) - O. semipolitus has the following diagnostic characters: carinae or rugulae extending posterad from the frontal lobes and surpassing the posterior eye orbits: one or more longitudinal rugulae on clypeus: fine reticulae on head and propodeum. Ochetomyrmex neopolitus is characterized by: frontal carinae never surpassing the anterior orbits of eyes: cephalic dorsum smooth and shining, devoid of microsculpture: clypeus normally smooth and shining: propodeum smooth and shining, with no apparent microsculpture.
 * Frontal carinae stretching posterad as fine rugulae and surpassing the posterior border of eye: frons with minute reticulate sculpture: clypeus normally with one or more fine longitudinal rugulae . . . . . Ochetomyrmex semipolitus
 * Frontal carinae never surpassing posterior margin of eye: head smooth and shining, devoid of microsculpture: clypeus normally smooth and shining . . . . . Ochetomyrmex neopolitus

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Suriname.

Nomenclature

 *  semipolitus. Ochetomyrmex semipolitus Mayr, 1878: 872 (w.) BRAZIL. Senior synonym of argentinus, bolivianus, mayri, subpolita: Fernández, 2003c: 638.
 * mayri. Ochetomyrmex mayri Forel, 1908c: 360 (w.) BRAZIL. Junior synonym of semipolitus: Fernández, 2003c: 638.
 * subpolita. Wasmannia subpolita Wheeler, W.M. 1916c: 8 (w.) GUYANA. Kempf, 1975c: 361 (q.m.); Wheeler, G.C. & Wheeler, J. 1977: 595 (l.). Combination in Ochetomyrmex: Kempf, 1961b: 511. Junior synonym of semipolitus: Fernández, 2003c: 638.
 * argentinus. Brownidris argentinus Kusnezov, 1957a: 276, pl. 4, figs. 1-13 (w.q.m.) ARGENTINA. Combination in Ochetomyrmex: Kempf, 1975c: 358. Junior synonym of semipolitus: Fernández, 2003c: 638.
 * bolivianus. Brownidris bolivianus Kusnezov, 1962b: 155, figs. 16, 26 (q.) BOLIVIA. Combination in Ochetomyrmex: Kempf, 1975c: 358. Junior synonym of semipolitus: Fernández, 2003c: 638.

Fernández (2003) - Queen and male: Not examined. The female and male of O. argentinus (Kusnezov) and the female of O. bolivianus (Kusnezov) maybe the sexual forms of this species. Kempf (1975) in his redescription of O. subpolitus ( = O. neopolitus), points out the petiole’s peduncle is as wide as long, but there are specimens of O. neopolitus with peduncles longer than wide or of similar length and width. The peduncle of the syntype of O. mayri (=O. semipolitus) is as wide as long, and the peduncle of the paratype of O. semipolitus becomes narrower as it approaches its insertion with the propodeum. The propodeal spine is also variable in shape as in O. subpolita: they may be low and subtriangular or very high and spiniform. Furthermore, there is a slight variation on the distinctive characters of the head: the cotype of Ochetomyrmex, described by Wheeler (1916) as O. subpolitus (=O. semipolitus), has a clypeus with no carinae and a smooth pronotum devoid of microsculpture (typical of O. neopolitus). Nevertheless, these specimens have a distinctive character that classifies them as O. semipolitus: the fine carinae or regulae that surpass the eyes and extend up to the posterior margin of the head. Perhaps the shiny and smooth clypeus induced Wheeler to believe that it was a different species, but besides these specimens, no other worker of O. semipolitus lacks regulae in the clypeus. The diagnostic characters that set the two species apart lie on the head, since the features of the rest of the body are of little use when trying to distinguish between species.

Worker
Fernández (2003) - Paratype LACM (other workers. N=5): HW 045 (0.41-0.50) HL 0.53 (0.50 - 0.54) SL 0.34 (030 - 0.39) EL 0.13 (0.10 - 0.12) WL 0.50 (0.45 - 0.55) PL 0.18 (0.18 - 0.25) PPL 0.15 (0.10 - 0.14) GL 0.79 (0.56 - 0 .57) TL 2.23 (1.85 - 2.14) CI 86 (83 - 93) SI 75 (73 - 78).

Diagnosis of worker: Frontal carinae diverging caudally as longitudinal rugulae, easily surpassing posterior margin of eye and ending near the posterior lateral corner. One to three longitudinal carinae on clypeus. Frons with minute reticulate sculpture.

Worker description. Head in frontal view nearly as broad as long, with convex to nearly straight posterior margin concave in Fig 1A; occipital corner narrowly rounded: sides of head convex, slightly narrower anteriorly. Mandible with strongly convex basal border, masticatory border with four teeth (occasionally five), basal and sub-basal smaller, apical tooth larger than subapical tooth. Median surface of clypeus convex, anterior border convex. Frontal carine diverging caudally as longitudinal rugulae, easily surpassing posterior border of eye and ending near posterior lateral corner. Compound eyes multifaceted, behind the middle of the head’s media line. Scape fails to reach posterior head borer by 1.5 times of their apical width. Mesosoma as in figure. Promesonotum in dorsal view longer than broad. Dorsum of pronotum with feebly carinated anterior border: promesonotal suture dorsally obsolete, laterally impressed. Propodeal dorsal margin nearly flat in side view, with two small teeth, subtriangular to spiniform in shape, much longer than broad. Met pleural lobes prominent and rounded. Propodeal spiracle situated in front of base of propodeal teeth. Bulla of the metasternal gland large and bulging. Petiole with anterior peduncle more or less as long as node, as long as broad or longer than broad. Two carinae in cephalic dorsum, each carinae extending from frontal lobe, several concentric carinae situated between inferior orbits of eyes and antennal receptacles, some longitudinal carinae between inferior orbits of eyes and mandibular bases, one to three longitudinal carinae on clypeus. Parts of head, mesosoma, petiole and postpetiole with minute rugulae, pronotal sculpturing sometimes feeble and hard to see. Four to five rows of erect and hort setae on head,  six to eight erect and short setae over mesosomal dorsum, two on propodeal dorsum, four on petiole, two on postpetiole and several on gaster. Most head setae less than 0.05 mm long. Mesosoma, petiole and postpetiole brown: head, gaster and appendages darker.