Strumigenys cosmostela

In Costa Rica (Longino, Ants of Costa Rica) Strumigenys cosmostela occurs in lowland wet forest, in leaf litter/soil on the forest floor. At La Selva Biological Station it is an infrequent species in Winkler and Berlese samples. Sampling within and beyond Costa Rica has shown this is a relatively common Strumigenys species.

Identification
Bolton (2000) - A member of the hindenburgi complex in the Strumigenys hindenburgi-group. The variations in pronotal sculpture and size and location of the proximal preapical tooth or denticle probably indicates that more than one species is concealed under this name. For the present I am leaving them all as cosmostela. In the sparse material currently available there seems to be a gradual morphoclinal change from predominantly rugulose to predominantly reticulate-punctate pronotal sculpture. The proximal preapical tooth or denticle varies markedly in both size and position, on occasion it is completely absent. When more material is available these features, together with density of gastral pilosity, may form a basis for the further resolution of this taxon. The species closest related to cosmostela, Strumigenys hindenburgi, has much-expanded upper scrobe margins that are about as wide as the maximum scape width. The hind femora of cosmostela are shorter and deeper than those of hindenburgi. In the former the hind femur is about 4.5 times longer than its maximum depth in posterior view, whereas in the latter the hind femur is about 5.5 longer than deep.

Longino (Ants of Costa Rica) - Differs from Strumigenys lanuginosa in having a second preapical tooth on mandible; smaller eyes composed of fewer than 10 facets; basal costae of gaster coarse rather than fine; smaller size and relatively shorter mandibles.

Distribution based on Regional Taxon Lists
Neotropical Region: Brazil, Colombia, Costa Rica, Ecuador, Guatemala, Honduras, Mexico, Peru, Venezuela.

Castes
Ergatoid queens have replaced winged queens completely (Silva & Brandao 2014).

Nomenclature

 *  cosmostela. Strumigenys cosmostela Kempf, 1975a: 413, figs. 1, 2 (w.) BRAZIL. See also: Bolton, 2000: 520.

Worker
Bolton (2000) - TL 2.2-2.5, HL 0.52-0.58, HW 0.42-0.48, CI 79-85, ML 0.30-0.36, MI 57-63, SL 0.29-0.32, SI 66-73, PW 0.26-0.32, AL 0.56-0.63 (10 measured).

With characters of hindenburgi complex. Mandible with a distal preapical tooth close to the apicodorsal tooth. Proximally with a smaller tooth or denticle that is very variable in size and position (sometimes varying within a single series), rarely absent. Apicoscrobal hair long and flagellate. Head densely reticulate-punctate, often with superimposed fine rugulae. Pronotal sculpture very variable: sometimes with strong spaced longitudinal rugae on an almost smooth to weakly punctate surface; in some the rugae lower, more rounded and fainter, or more numerous and more closely packed, beaded with fine punctures and appearing delicately sulcate; in some series rugular sculpture almost entirely suppressed, the surface appearing reticulate-punctate with sparse minute rugulose vestiges. With head in full-face view upper scrobe margin a carina, much narrower at maximum than the maximum width of the scape. Hind femora in posterior view deep, in dorsal view compressed from side to side. Disc of postpetiole with rugulose or costulate sculpture. Basigastral costulae sharply defined, varying from slightly shorter to slightly longer than the postpetiole disc. First gastral tergite with numerous long flagellate hairs, varying in density between series but not as abundant as in Strumigenys hindenburgi.

Type Material
Bolton (2000) - Holotype worker, BRAZIL: Para, Iriboca near Belem, Pirelli Plantation, 15.viii.1962, BF-18 (W. L. Brown). Paratype worker, BRAZIL: Para, Utinga tract, near Belem, 12.viii.1962, BF-11 (W. L. Brown) [examined].

References based on Global Ant Biodiversity Informatics

 * Bezdeckova K., P. Bedecka, and I. Machar. 2015. A checklist of the ants (Hymenoptera: Formicidae) of Peru. Zootaxa 4020 (1): 101–133.
 * Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
 * 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.
 * Fleck M. D., E. Bisognin Cantarelli, and F. Granzotto. 2015. Register of new species of ants (Hymenoptera: Formicidae) in Rio Grande do Sul state. Ciencia Florestal, Santa Maria 25(2): 491-499.
 * 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, M. Leponce, J. Orivel, R. Silvestre, Heraldo L. Vasconcelos, and A. Dejean. 2013. Leaf-litter ant communities (Hymenoptera: Formicidae) in a pristine Guianese rainforest: stable functional structure versus high species turnover. Myrmecological News 19: 43-51.
 * 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.
 * Longino J. T. L., and M. G. Branstetter. 2018. The truncated bell: an enigmatic but pervasive elevational diversity pattern in Middle American ants. Ecography 41: 1-12.
 * Longino J. T., and R. K. Colwell. 2011. Density compensation, species composition, and richness of ants on a neotropical elevational gradient. Ecosphere 2(3): 16pp.
 * Longino J. et al. ADMAC project. Accessed on March 24th 2017 at https://sites.google.com/site/admacsite/
 * Ryder Wilkie K.T., A. L. Mertl, and J. F. A. Traniello. 2010. Species Diversity and Distribution Patterns of the Ants of Amazonian Ecuador. PLoS ONE 5(10): e13146.doi:10.1371/journal.pone.0013146
 * Silva R.R., and C. R. F. Brandao. 2014. Ecosystem-Wide Morphological Structure of Leaf-Litter Ant Communities along a Tropical Latitudinal Gradient. PLoSONE 9(3): e93049. doi:10.1371/journal.pone.0093049
 * Silva T. S. R., and C. R. F. Brandao. 2014. Further Ergatoid Gyne Records in the Ant Tribe Dacetini (Formicidae: Myrmicinae). Neotrop. Entomol DOI 10.1007/s13744-013-0192-7
 * Silva T. S. R., and R. M. Feitosa. 2019. Using controlled vocabularies in anatomical terminology: A case study with Strumigenys (Hymenoptera: Formicidae). Arthropod Structure and Development 52: 1-26.
 * Sosa-Calvo J., T. R. Schultz, and J. S. LaPolla. 2010. A review of the dacetine ants of Guyana (Formicidae: Myrmicinae). Journal of Hymenoptera Research 19: 12-43.
 * Suguituru S. S., M. Santina de Castro Morini, R. M. Feitosa, and R. Rosa da Silva. 2015. Formigas do Alto Tiete. Canal 6 Editora 458 pages
 * Ulyssea M. A., C. R. F. Brandao. 2013. Catalogue of Dacetini and Solenopsidini ant type specimens (Hymenoptera, Formicidae, Myrmicinae) deposited in the Museu de Zoologia da Universidade de Sao Paulo, Brazil. Papies Avulsos de Zoologia 53(14): 187-209.
 * 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