Acanthostichus laticornis

Mackay (1996) - One nest found under large rock, numerous workers, single female, apparently in a termite nest. A staphylinid (Aleocharinae: Paradoxenusa silvestrii Bruch) occurs with this species (Bruch, 1937). These ants forage in columns similar to Eciton, but smaller; they prey on termites (Kusnezov, 1962).

Identification
A member of the serratulus species complex. Mackay (1996) - The worker is similar to that of Acanthostichus kirbyi, but is easily distinguished by the short, thick scapes with a well formed angle (Fig. 4). The female is very similar to that of Acanthostichus quadratus, but differs in that the anterior surface of the scape is angulate and the female of this species possesses a well developed malar groove. The male is almost indistinguishable from that of A. laticornis. It differs primarily in that the sculpture of the propodeum is rougher.

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

Nomenclature

 * . Acanthostichus laticornis Forel, 1908c: 345 (w.) PARAGUAY.
 * Type-material: lectotype worker (by designation of Mackay, 1996: 159), 12 paralectotype workers.
 * Type-locality: lectotype Paraguay: San Bernardino (Fiebrig); paralectotypes with same data.
 * [Note: Mackay, 1996: 159, adds that 2 more possible original syntypes are in MACN.]
 * Type-depositories: MHNG (lectotype); MHNG, NHMB (paralectotypes).
 * Santschi, 1933e: 106 (m.); Mackay, 1996: 158 (q.).
 * Combination in A. (Acanthostichus): Emery, 1911d: 13.
 * Status as species: Emery, 1911d: 13; Forel, 1911c: 288; Santschi, 1916e: 365; Santschi, 1933e: 106; Wheeler, W.M. 1934g: 162 (in key); Kusnezov, 1962a: 131; Kempf, 1972a: 10; Brown, 1975: 42; Zolessi, et al. 1988: 3; Bolton, 1995b: 54; Mackay, 1996: 158 (redescription); Wild, 2007b: 23.
 * Senior synonym of obscuridens: Kusnezov, 1962a: 131; Kempf, 1972a: 10; Brown, 1975: 42; Bolton, 1995b: 54; Mackay, 1996: 158.
 * Distribution: Argentina, Brazil, Paraguay, Uruguay.
 * obscuridens. Acanthostichus laticornis var. obscuridens Santschi, 1934c: 23 (w.q.m.) ARGENTINA (Misiones).
 * Type-material: lectotype worker (by designation of Mackay, 1996: 159), 9 paralectotype workers.
 * Type-locality: lectotype Argentina: Misiones, Loreto, 24.viii.1933 (A.A. Ogloblin); paralectotypes with same data.
 * Type-depositories: NHMB (lectotype); MZSP, NHMB (paralectotypes).
 * Bruch, 1934a: 4 (q.m.).
 * Subspecies of laticornis: Bruch, 1934a: 4.
 * Junior synonym of laticornis: Kusnezov, 1962a: 131; Kempf, 1972a: 10; Brown, 1975: 42; Bolton, 1995b: 54; Mackay, 1996: 158.

Worker
Mackay (1996) - HL 1.01-1.31, HW 0.86-1.20, SL 0.50-0.66, SW 0.23-0.29, FL 0.70-0.95, FW 0.24-0.35, WL 1.28-1.73, PW 0.38-0.53, PL 0.46-0.65, SI 49-50, CI 85-91, PI 123-124, FI 271-295, SL/SW 2.22-2.30.

Mandibles without teeth. but with slight undulations. lateral clypeal teeth well developed; scape relatively short and thick. with well developed angle (Fig. 4); vertex concave; petiole somewhat elongate. subpetiolar process rounded anteriorly with sharp ventral apex posteriorly (Fig. 27); femur not thickened.

Queen
Mackay (1996) - HL 1.64, HW 1.82, SL 0.73, SW 0.34, EL 0.20, WL 2.20, PW 1.60, PL 0.81, SI 45, CI 111, PI 51, SL/SW 2.15.

Mandibles without teeth; lateral clypeal angles well formed; malar groove well developed. but extending only ½ distance to eye; outer margin of scape angulate as in worker; femora not incrassate; petiole much wider than long, wider at posterior end. Entire ant covered with scarce, flexuous hairs, concolorous light brown.

Male
Mackay (1996) - HL 0.74-0.95, HW (posterior to eye) 0.66-0.96, SL 0.20-0.28, EL 0.39-0.48, WL 1.66-1.68, PW 0.36-0.39, PL 0.45-0.51, SI 27-29, CI 90-101, PI 124-132.

The male is similar to those of other species in the genus and is difficult to separate. Apparently the shape of the volsellae, shape of the petiole and sculpturing of the propodeum will separate this species from some of the other species (see key). The scape is slightly thickened, but bears no resemblance to the characteristic shape of the scape of the worker.

Type Material
Mackay (1996) - Worker. PARAGUAY: San Bernardino 15 cotype workers (12 worker cotypes,, 1 worker cotype, , 2 workers, possibly cotypes, ) [all seen]. Acanthostichus laticornis, lectotype worker (here designated) (MHNG) and eleven paralectotype workers (MHNG), 1 paralectotype worker (NHMB), PARAGUAY. San Bernardino (Fiebig); A. laticornis Forel worker type Formic #5944., oll. Forel [all seen]. Two possible cotype workers in MACN. Acanthostichus laticornis var. obscuridens, ARGENTINA. Misiones. Estacion Experimental Loreto. Dr. A. A. Oglobin, 24-viii-1933, female, lectotype worker (here designated) (NHMB) and 4 paralectotype workers (NHMB) [seen], five paralectotype workers [seen].

References based on Global Ant Biodiversity Informatics

 * Borowiec M. L. 2016. Generic revision of the ant subfamily Dorylinae (Hymenoptera, Formicidae). ZooKeys 608: 1–280.
 * Brown W. L., Jr. 1975. Contributions toward a reclassification of the Formicidae. V. Ponerinae, tribes Platythyreini, Cerapachyini, Cylindromyrmecini, Acanthostichini, and Aenictogitini. Search Agric. (Ithaca N. Y.) 5(1): 1-115.
 * Bruch C. 1934. La hembra dictadiforme de Acanthostichus laticornis For. v. obscuridens Sants. (Hymenoptera Formicidae). Revista de la Sociedad Entomológica Argentina 6: 3-8.
 * 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.
 * Emery C. 1911. Hymenoptera. Fam. Formicidae. Subfam. Ponerinae. Genera Insectorum 118: 1-125.
 * Esteves F. A., C. R. F. Brandao, and L. P. Prado. 2011. The type specimens of Dorylomorph ants (Hymenoptera, Formicidae: Aenictinae, Ecitoninae, Cerapachyinae, Leptanilloidinae) deposited in the Museu de Zoologia da Universidade de Sao Paulo, Brazil. Papeis Avulsos de Zoologia 51(22): 341-397.
 * Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Kusnezov N. 1962. El género Acanthostichus Mayr (Hymenoptera, Formicidae). Acta Zoologica Lilloana 18: 121-138.
 * Kusnezov N. 1978. Hormigas argentinas: clave para su identificación. Miscelánea. Instituto Miguel Lillo 61:1-147 + 28 pl.
 * MacKay W. P. 1996. A revision of the ant genus Acanthostichus (Hymenoptera: Formicidae). Sociobiology 27: 129-179
 * Santschi F. 1916. Formicides sudaméricains nouveaux ou peu connus. Physis (Buenos Aires). 2: 365-399.
 * Santschi F. 1933. Fourmis de la République Argentine en particulier du territoire de Misiones. Anales de la Sociedad Cientifica Argentina. 116: 105-124.
 * Santschi F. 1934. Fourmis de Misiones et du Chaco argentin. Revista de la Sociedad Entomológica Argentina. 6: 23-34.
 * Schmidt F. A., and R. R. C. Solar. Is it important to collect hypogaeic ants? How to collect them? Biológico, São Paulo 69(2): 267-270.
 * Schmidt, F.A. and R.R.C Solar. 2010. Hypogaeic pitfall traps: methodological advances and remarks to improve the sampling of a hidden ant fauna. Insectes Sociaux 57:261-266.
 * Vittar, F. 2008. Hormigas (Hymenoptera: Formicidae) de la Mesopotamia Argentina. INSUGEO Miscelania 17(2):447-466
 * Wild, A. L. "A catalogue of the ants of Paraguay (Hymenoptera: Formicidae)." Zootaxa 1622 (2007): 1-55.
 * Zolessi L. C. de, Y. P. Abenante, and M. E. de Philippi. 1988. Lista sistematica de las especies de Formicidos del Uruguay. Comun. Zool. Mus. Hist. Nat. Montev. 11: 1-9.
 * Zolessi L. C. de; Y. P. de Abenante, and M. E. Philippi. 1989. Catálogo sistemático de las especies de Formícidos del Uruguay (Hymenoptera: Formicidae). Montevideo: ORCYT Unesco, 40 + ix pp.
 * de Zolessi, L.C., Y.P. de Abenante and M.E. Phillipi. 1989. Catalago Systematico de las Especies de Formicidos del Uruguay (Hymenoptera: Formicidae). Oficina Regional de Ciencia y Technologia de la Unesco para America Latina y el Caribe- ORCYT. Montevideo, Uruguay