Strumigenys sevesta

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Strumigenys sevesta
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Attini
Genus: Strumigenys
Species: S. sevesta
Binomial name
Strumigenys sevesta
Bolton, 2000

Strumigenys sevesta inb0003211882 p 1 high.jpg

Strumigenys sevesta inb0003211882 d 1 high.jpg

Specimen Labels

Occurs in cloud forest and mid-elevation montane forest down to 300m (Longino, Ants of Costa Rica).

Identification

Bolton (2000) - A member of the Strumigenys emeryi-group. The only species in the group completely to lack spongiform tissue ventrally on the petiole. This, coupled with the absence of a lateral spongiform lobe on the petiole node, is diagnostic.

Longino (Ants of Costa Rica) - Apical fork of mandible with one intercalary tooth; mandible with no preapical teeth; gaster smooth and shining; gaster with erect, linear, somewhat stiffened setaes.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Neotropical Region: Costa Rica (type locality).


Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Strumigenys were once thought to be rare. The development and increased use of litter sampling methods has led to the discovery of a tremendous diversity of species. Many species are specialized predators (e.g. see Strumigenys membranifera and Strumigenys louisianae). Collembola (springtails) and other tiny soil arthropods are typically favored prey. Species with long linear mandibles employ trap-jaws to sieze their stalked prey (see Dacetine trap-jaws). Larvae feed directly on insect prey brought to them by workers. Trophallaxis is rarely practiced. Most species live in the soil, leaf litter, decaying wood or opportunistically move into inhabitable cavities on or under the soil. Colonies are small, typically less than 100 individuals but in some species many hundreds. Moist warm habitats and micro-habitats are preferred. A few better known tramp and otherwise widely ranging species tolerate drier conditions. Foraging is often in the leaf litter and humus. Workers of many species rarely venture above ground or into exposed, open areas. Individuals are typically small, slow moving and cryptic in coloration. When disturbed individuals freeze and remain motionless. Males are not known for a large majority of species.

Castes

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

  • sevesta. Strumigenys sevesta Bolton, 2000: 518, figs. 307, 340 (w.) COSTA RICA.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Holotype. TL 2.8, HL 0.70, HW 0.56, CI 80, ML 0.42, MI 60, SL 0.47, SI 84, PW 0.35, AL 0.73. Mandible without trace of preapical dentition. Apicoscrobal hair and pronotal humeral hair flagellate. Both pairs of erect hairs on cephalic dorsum stiff and simple; mesonotum with a similar but more acutely pointed pair of erect hairs. Petiole, postpetiole and first gastral tergite with stiff simple hairs that are erect, shallowly curved and mostly acute apically. Pronotal dorsum reticulate-punctate with superimposed fine rugular sculpture. Mesopleuron smooth, metapleuron and side of propodeum reticulate-punctate. Propodeum with a pair of narrow short spines that are subtended by vestigial carinae down the declivity; no lamellae present and propodeal lacuna absent. Ventral surface of petiole without spongiform tissue except for a minute process at extreme posteroventral angle. Lateral spongiform lobe of petiole node absent or no more than a slight thickening of the apex of the posterior collar. In profile lateral spongiform appendage of postpetiole reduced to a narrow cuticular collar; ventral spongiform lobe very small, much smaller than the area of exposed cuticle of the disc. Petiole node in dorsal view broader than long, reticulate-punctate; disc of post petiole finely reticulate-punctate everywhere. Basigastral costulae minute and feebly defined, much shorter than length of postpetiole disc.

Paratypes. TL 2.7-3.0, HL 0.68-0.74, HW 0.52-0.61, CI 76-82, ML 0.41-0.44, MI 58-62, SL 0.46-0.49, SI 80-88, PW 0.31-0.36, AL 0.70-0.80 (10 measured). As holotype but in some the apices of the mesonotal standing hairs, and of some on the gaster, may be markedly thinner than their shafts and more strongly curved or even hooked. Preapical dentition is uniform throughout type-series, but given its variability in other species of the group some variation should perhaps be expected.

Type Material

Holotype worker, Costa Rica: Provo Puntarenas, Monteverde, 1360 m., 10°18'N, 84°48'W, 16.iv.1988, forest litter sample, ground, #1997-S (J. Longino) (The Natural History Museum).

Paratypes. Costa Rica: 2 workers from same locality but 1500 m., 10.xii.1987, cloud forest litter sample, ground, #1972-S (J. Longino); 1 worker from same locality but 1300 m., 21.xii.1986, wet forest litter sample, #1487-S (J. Longino); 2 workers with same data but 1500 m., 16.iv.1989, wet forest ex sifted leaf litter, #2467-S and #2468-S (J. Longino); 1 worker, Provo Heredia, 1 3 km. SSW Pto Viejo, 10°21'N, 84°03'W, 300 m., 17.vii.1986, wet forest litter sample, #1390-S (J. Longino); 3 workers, Provo Alajuela, 3 km. E Monteverde, 10°18'N, 84°47'W, 1400 m., 26.iv.1990, wet forest ex sifted leaf litter, #2674-S (J. Longino); 2 workers, Provo Alajuela, Rio Penas Biancas, 10°19'N, 84°43'W, 800 m., 26-28.iv.1987, wet forest ex sifted leaf litter, #1579-S (J. Longino) (Instituto Nacional de Biodiversidad, The Natural History Museum, Museum of Comparative Zoology, Los Angeles County Museum of Natural History, John T. Longino Collection).

References

  • Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028. (page 518, figs. 307, 340 worker described)

References based on Global Ant Biodiversity Informatics

  • Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
  • Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
  • 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/
  • Valenzuela-Gonzalez J., A. V. Parra-Cabanas, L. Quiroz-Robledo, D. L. Martinez-Tlapa, and E. D. Montes-de-Oca-Torres. 2013. Variación de la mirmecofauna en un gradiente altitudinal en la región central de Veracruz, México. In Formicidae de Mexico (eds. M. Vasquez-Bolanos, G. Castano-Meneses, A. Cisneros-Caballero, G. A. Quiroz-Rocha, and J. L. Navarrete-Heredia) p 75-82.