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, Peru, 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.

References based on Global Ant Biodiversity Informatics

 * Alonso L. E., and J. A. Helms. 2013. A Rapid Assessment of the Ants of the Grensgebergte and Kasikasima Regions of Southeastern Suriname. A Rapid Biological Assessment of the Upper Palumeu River Watershed (Grensgebergte and Kasikasima) of Southeastern Suriname: 109-118.
 * Boscardin J., J. Garlet, and E. Correa Costa. 2012. Mirmecofauna epigéica (Hymenoptera: Formicidae) em plantios de Eucalyptus spp. (Myrtales: Myrtaceae) na região oeste do estado do Rio Grande do Sul, Brasil. Entomotropica 27(3): 119-128.
 * Brandao, C.R.F. 1991. Adendos ao catalogo abreviado das formigas da regiao neotropical (Hymenoptera: Formicidae). Rev. Bras. Entomol. 35: 319-412.
 * Cuezzo, F. 1998. Formicidae. Chapter 42 in Morrone J.J., and S. Coscaron (dirs) Biodiversidad de artropodos argentinos: una perspectiva biotaxonomica Ediciones Sur, La Plata. Pages 452-462.
 * Delabie J. H. C., R. Céréghino, S. Groc, A. Dejean, M. Gibernau, B. Corbara, and A. Dejean. 2009. Ants as biological indicators of Wayana Amerindian land use in French Guiana. Comptes Rendus Biologies 332(7): 673-684.
 * Drose W., L. R. Podgaiski, C. Fagundes Dias, M. de Souza Mendonca. 2019. Local and regional drivers of ant communities in forest-grassland ecotones in South Brazil: A taxonomic and phylogenetic approach. Plos ONE 14(4): e0215310.
 * Ettershank G. 1966. A generic revision of the world Myrmicinae related to Solenopsis and Pheidologeton (Hymenoptera: Formicidae). Aust. J. Zool. 14: 73-171.
 * Fernandes I., and J. de Souza. 2018. Dataset of long-term monitoring of ground-dwelling ants (Hymenoptera: Formicidae) in the influence areas of a hydroelectric power plant on the Madeira River in the Amazon Basin. Biodiversity Data Journal 6: e24375.
 * Fernández F. 2003. Myrmicine ants of the genera Ochetomyrmex and Tranopelta (Hymenoptera: Formicidae). Sociobiology 41: 633-661
 * Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
 * Fichaux M., B. Bechade, J. Donald, A. Weyna, J. H. C. Delabie, J. Murienne, C. Baraloto, and J. Orivel. 2019. Habitats shape taxonomic and functional composition of Neotropical ant assemblages. Oecologia 189(2): 501-513.
 * Forel A. 1908. Ameisen aus Sao Paulo (Brasilien), Paraguay etc. gesammelt von Prof. Herm. v. Ihering, Dr. Lutz, Dr. Fiebrig, etc. Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wien 58: 340-418.
 * Franco W., N. Ladino, J. H. C. Delabie, A. Dejean, J. Orivel, M. Fichaux, S. Groc, M. Leponce, and R. M. Feitosa. 2019. First checklist of the ants (Hymenoptera: Formicidae) of French Guiana. Zootaxa 4674(5): 509-543.
 * Groc S., J. H. C. Delabie, F. Fernandez, F. Petitclerc, B. Corbara, M. Leponce, R. Cereghino, and A. Dejean. 2017. Litter-dwelling ants as bioindicators to gauge the sustainability of small arboreal monocultures embedded in the Amazonian rainforest. Ecological Indicators 82: 43-49.
 * Groc S., J. Orivel, A. Dejean, J. Martin, M. Etienne, B. Corbara, and J. H. C. Delabie. 2009. Baseline study of the leaf-litter ant fauna in a French Guianese forest. Insect Conservation and Diversity 2: 183-193.
 * Kempf W. W. 1961. A survey of the ants of the soil fauna in Surinam (Hymenoptera: Formicidae). Studia Entomologica 4: 481-524.
 * Kempf W. W. 1975. Miscellaneous studies on neotropical ants. VI. (Hymenoptera, Formicidae). Studia Entomologica 18: 341-380.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Kusnezov N. 1952. El género Wasmannia en la Argentina (Hymenoptera, Formicidae). Acta Zoologica Lilloana 10: 173-182.
 * Kusnezov N. 1956. Claves para la identificación de las hormigas de la fauna argentina. Idia 104-105: 1-56.
 * Kusnezov N. 1957. Die Solenopsidinen-Gattungen von Südamerika (Hymenoptera, Formicidae). Zoologischer Anzeiger 158: 266-280.
 * Kusnezov N. 1962. Una nueva especie del género Brownidris Kusnezov (Hymenoptera, Formicidae). Acta Zoologica Lilloana 18: 155-161.
 * Lapolla, J.S., T. Suman, J. Soso-Calvo and T.R. Schultz. 2006. Leaf litter ant diversity in Guyana. Biodiversity and Conservation 16:491510
 * Lopes M. C., G. P. A. Lamarre, C. Baraloto, P. V. A. Fine, A. Vincentini, and F. B. Baccaro. 2019. The Amazonas-trap: a new method for sampling plant-inhabiting arthropod communities in tropical forest understory. Entomologia Experimentalis et Applicata https://doi.org/10.1111/eea.12797
 * Luederwaldt H. 1918. Notas myrmecologicas. Rev. Mus. Paul. 10: 29-64.
 * Majer J. D., and J. H. C. Delabie. 1994. Comparison of the ant communities of annually inundated and terra firme forests at Trombetas in the Brazilian Amazon. Insectes Sociaux 41: 343-359.
 * Meurer E., L. D. Battirola, M. I. Marques, and J. H. C. Delabie. 2015. New records  and  distribution  for  the  Neotropical  ant  genus Ochetomyrmex Mayr (Hymenoptera: Formicidae). Sociobiology 62(2): 266-269.
 * Pires de Prado L., R. M. Feitosa, S. Pinzon Triana, J. A. Munoz Gutierrez, G. X. Rousseau, R. Alves Silva, G. M. Siqueira, C. L. Caldas dos Santos, F. Veras Silva, T. Sanches Ranzani da Silva, A. Casadei-Ferreira, R. Rosa da Silva, and J. Andrade-Silva. 2019. An overview of the ant fauna (Hymenoptera: Formicidae) of the state of Maranhao, Brazil. Pap. Avulsos Zool. 59: e20195938.
 * Ramos L. de S., C. G. S. Marinho, R. Zanetti, and J. H. C. Delabie. 2003. Impacto de iscas formicidas granuladas sobre a mirmecofauna não-alvo em eucaliptais segundo duas formas de aplicacação / Impact of formicid granulated baits on non-target ants in eucalyptus plantations according to two forms of application. Neotropical Entomology 32(2): 231-237.
 * Ribeiro L. F., R. R. C. Solar, T. G. Sobrinho, D. C. Muscardi, J. H. Schoereder, and A. N. Andersen. 2019. Different trophic groups of arboreal ants show differential responses to resource supplementation in a neotropical savanna. Oecologia 190(2): 433-443.
 * Vasconcelos, H.L., J.M.S. Vilhena, W.E. Magnusson and A.L.K.M. Albernaz. 2006. Long-term effects of forest fragmentation on Amazonian ant communities. Journal of Biogeography 33:1348-1356
 * Vittar, F. 2008. Hormigas (Hymenoptera: Formicidae) de la Mesopotamia Argentina. INSUGEO Miscelania 17(2):447-466
 * Wheeler W. M. 1916. Ants collected in British Guiana by the expedition of the American Museum of Natural History during 1911. Bulletin of the American Museum of Natural History 35: 1-14.
 * Wild, A. L. "A catalogue of the ants of Paraguay (Hymenoptera: Formicidae)." Zootaxa 1622 (2007): 1-55.