Strumigenys dyseides

Collection records from Guyana and French Guiana show this ant inhabits forest leaf-litter.

Identification
Bolton (2000) - A member of the Strumigenys silvestrii-group. Within the group the species dyseides, Strumigenys gytha, Strumigenys quadrua, Strumigenys ruta and Strumigenys skia share the following characters.

1 Ventral surface of petiole does not have spongiform tissue.

2 Cephalic dorsum does not have a pair of short erect hairs near highest point of vertex (if any short standing hairs are present they are restricted to a single pair at the occipital margin).

3 With head in full-face view all spatulate or spoon-shaped hairs that fringe the upper scrobe margin are curved anteriorly.

4 Pilosity of the first gastral tergite is entirely of long flagellate hairs; without any other form of hair present.

S. quadrua is instantly diagnosed among these five species as it has only 4-segmented antennae and lacks a spiniform distal preapical tooth. The four remaining species form two related pairs. S. dyseides and gytha have the flagellate hairs on the first gastral tergite very fine and uniformly slender throughout their lengths, and standing hairs are absent from the mesonotum. In ruta and skia mesonotal standing hairs are present and the flagellate hairs on the first gastral tergite are thick for most or all of their lengths, usually appearing roughly ribbon-like for much of their lengths in any view. The components of each of these species-pairs can easily be separated by the characters given in the key.

Distribution based on Regional Taxon Lists
Neotropical Region: Argentina, Colombia.

Nomenclature

 *  dyseides. Strumigenys dyseides Bolton, 2000: 552, fig. 326 (w.) COLOMBIA.

Worker
Holotype. TL 1.8, HL 0.45, HW 0.34, CI 76, ML 0.30, MI 67, SL 0.28, SI 82, PW 0.23, AL 0.47. Spiniform preapical tooth of mandible separated from apicodorsal tooth by a distance about equal to its length. A minute preapical denticle also present, just proximal of mandibular midlength. Scape with a pronounced subbasal bend, the curved hairs on its leading edge slightly shorter than the maximum scape width. Ground-pilosity of head short and spoon-shaped; a pair of erect short simple hairs present on dorsum close to occipital margin; apicoscrobal hair fine. Promesonotum with short spatulate to spoon-shaped ground-pilosity; pronotal humeral hair very finely flagellate; mesonotum without standing elongate hairs of any form. Hairs on first gastral tergite sparse, flagellate, extremely fine. Pleurae and side of propodeum smooth. Propodeum with a pair of small teeth, subtended by a lamella that is obtusely triangular at the base of the declivity; posterior (free) margin of lamella shallowly concave. With petiole in profile the ventral surface without spongiform tissue; lateral spongiform lobe of petiole large and conspicuous; height of anterior face of node greater than length of its dorsum (excluding posterior collar). Petiole node in dorsal view broader than long; disc of postpetiole smooth and shining. Basigastral costulae longer than disc of postpetiole, toward the centre of the tergite the longest costulae exceed one-third the length of the sclerite.

Type Material
Holotype worker, Colombia: Putumayo, Villa Garzon, 23.vii.1977 (D. Jackson).

References based on Global Ant Biodiversity Informatics

 * 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.
 * 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.
 * Medeiros Macedo L. P., E. B. Filho, amd J. H. C. Delabie. 2011. Epigean ant communities in Atlantic Forest remnants of São Paulo: a comparative study using the guild concept. Revista Brasileira de Entomologia 55(1): 7578.
 * 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.