Strumigenys excisa

Inhabits wet forest leaf litter. The type specimen (from Tuli Creek, near San Miguel, Nicaragua) was in the stomach of a toad, Dendrobates tinctorius, found on the forest floor (Weber 1934, Brown 1953). In Costa Rica, I obtained a series of workers in a Winkler sample of forest floor litter from the Penas Blancas Valley, at 800m elevation. Project ALAS, at La Selva Biological Station, produced a single worker from a Berlese extraction of a soil/litter core (Longino, Ants of Costa Rica). Subsequent sampling has yielded many collections of S. excisa from litter samples in other wet forest locations in Costa Rica.

Identification
Bolton (2000) - A member of the excisa-complex in the Strumigenys excisa-group. Two known species are closely related to excisa, Strumigenys dontopagis and Strumigenys asaphes; characters differentiating the three are compared under the last two names.

Longino (Ants of Costa Rica) - Mandible short and curving downward in profile; lateral head capsule with the antennal scrobe mostly or entirely smooth and shining; propodeal spines present (former Glamyromyrmex); leading edge of scape with long erect setae directed anteriorly or apically, not toward base of scape; disc of postpetiole in dorsal view very broadly U-shaped or V-shaped, with an extremely deeply concave anterior face; spongiform tissue absent from ventral surface of petiole, postpetiole and first gastral sternite; face coarsely rugose over disk, except for narrow median smooth area; face with flexuous setae; setae on face and mesosoma long, abundant, and erect.

Distribution based on Regional Taxon Lists
Neotropical Region: Belize, Costa Rica, Guatemala, Honduras, Mexico, Nicaragua.

Nomenclature

 *  excisa. Codiomyrmex excisus Weber, 1934a: 51, fig. 9 (w.) NICARAGUA. Combination in Borgmeierita: Brown, 1953g: 23; in Glamyromyrmex: Brandão, 1991: 344; in Pyramica: Bolton, 1999: 1672; in Strumigenys: Baroni Urbani & De Andrade, 2007: 119. See also: Bolton, 2000: 173.

Worker
Bolton (2000) - TL 2.2-2.3, HL 0.55-0.60, HW 0.47-0.50, CI 80-85, ML 0.11-0.13, MI 18-22, SL 0.23-0.26, SI 51-54, PW 0.28-0.31, AL 0.57-0.62 (6 measured).

Clypeus glassy smooth, with widely spaced minute punctures from which hairs arise. Behind the clypeus the cephalic dorsum finely longitudinally rugulose, most densely so away from the midline on the occipital lobes. Sides of alitrunk and propodeal declivity are smooth and shining, but dorsum of alitrunk has fine longitudinal rugular sculpture. Dorsum of petiole node has some fine disorganised short rugulae but disc of postpetiole is smooth. Basigastral costulae are feebly developed on each side of a median gap where the cuticle of the tergite is smooth. Spaces between basigastral costulae contain faint superficial shagreening. Dorsum of clypeus with suberect fine straight simple hairs. Cephalic dorsum with abundant standing simple pilosity. Dorsolateral margins of head in full-face view with abundant freely projecting fine hairs, some of which are long and subflagellate to flagellate. Scapes with scattered proj ecting hairs on the leading edge. Dorsal surfaces of club segments of antennae with long stiff suberect simple hairs that are at least as long as the maximum thickness of the segments. Dorsal alitrunk with abundant long fine simple hairs; pronotal humeral hair similar to other hairs but longer and subflagellate. Dorsal (outer) surfaces of hind tibiae and basitarsi with numerous long fine standing hairs that are distinctly longer than the segments from which they arise. Dorsa of waist segments and gaster clothed with abundant soft curved to flexuous standing hairs.

Type Material
Holotype worker, NICARAGUA: San Mejuel, Tuli Creek, xi.1916, from stomach of tree toad Dendrobates tinetorum, no. 2821-3433 (G. H. Noble) (parts card-pointed, other parts on microscope slide) [examined].

References based on Global Ant Biodiversity Informatics

 * Bolton, B. 2000. The Ant Tribe Dacetini. Memoirs of the American Entomological Institute 65
 * Brown W. L., Jr. 1953. Revisionary studies in the ant tribe Dacetini. Am. Midl. Nat. 50: 1-137.
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * 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).
 * Longino J. T. 2013. Ants of Honduras. Consulted on 18 Jan 2013. https://sites.google.com/site/longinollama/reports/ants-of-honduras
 * Longino J. T. 2013. Ants of Nicargua. Consulted on 18 Jan 2013. https://sites.google.com/site/longinollama/reports/ants-of-nicaragua
 * 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/
 * Weber N. A. 1934. Notes on neotropical ants, including the descriptions of new forms. Revista de Entomologia (Rio de Janeiro) 4: 22-59.