P. tenuissimus can be distinguished from Pseudomyrmex subtilissimus by its darker color, smaller size, and longer petiole. It differs from Pseudomyrmex spiculus by its smaller size and more elongate head (compare HW and CI).
Distribution based on Regional Taxon Lists
Neotropical Region: Belize, Bolivia, Brazil (type locality), Colombia, Costa Rica, Ecuador, El Salvador, French Guiana, Greater Antilles, Guatemala, Guyana, Honduras, Jamaica, Mexico, Nicaragua, Panama, Paraguay, Peru, Suriname, Trinidad and Tobago, Venezuela.
Distribution based on AntMaps
Distribution based on AntWeb specimens
Check data from AntWeb
Although P. tenuissimus is the most common member of the P. subtilissimus group, most collections appear to based on scattered foragers. In Costa Rica, Panama, and Colombia, I have encountered workers foraging on vegetation in a variety of habitats including rain forest, rain forest edge, old field/pasture, and tropical dry forest. I have seen nests only twice: one was a small colony containing a single dealate queen, seven workers, and brood, in the dead, fibrous twig of a woody liana, in tropical dry forest (northern Colombia); the other was a nest of 13 workers, 16 alate queens, and brood in the dead twig of a thorny vine at the edge of disturbed second-growth rain forest (Edo. Barinas, Venezuela). Mann (1916:426) recorded a colony from Maranhao, Brazil "taken from beneath a loose piece of bark", an unusual nest-site for Pseudomyrmex as Mann himself remarks.
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- tenuissimus. Pseudomyrma subtilissima subsp. tenuissima Emery, 1906c: 119 (w.) BRAZIL. Wheeler, G.C. & Wheeler, J. 1973d: 207 (l.). Combination in Pseudomyrmex: Kempf, 1972a: 224. Raised to species and senior synonym of culmicola: Ward, 1989: 432.
- culmicola. Pseudomyrma culmicola Forel, 1912g: 27 (w.) TRINIDAD. Combination in Pseudomyrmex: Kempf, 1972a: 217. Junior synonym of tenuissimus: Ward, 1989: 432.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
Ward (1989) - measurements (n=30, except for FI where n=29). HL 0.S2-0.93, HW 0.48-0.53, MFC 0.0l1-0.033, CI 0.56-0.62, OI 0.50-0.58, REL 0.48-0.53, REL2 0.84-0.92, OOI 0.22-0.89, VI 0.85-0.90, FCI 0.023-0.066, SI 0.39-0.46, SI2 0.44-0.54, FI 0.52-0.60, PDI 1.58-2.14, MPI 0.022-0.055, NI 0.55-0.64, PLI 0.54-0.66, PWI 0.49-0.60, PPWI 1.05-1.34.
diagnosis. Similar to P. spiculus (q.v.) except as follows: distinctly smaller, head more elongate (HW 0.48-0.53, CI 0.56-0.62). Basal face of propodeum flatter, forming a more distinct angle with the dec1ivitous face. Body color more uniformly brown to grey-brown, the pronotum, petiole, and postpetiole only slightly, or not at all, contrastingly lighter.
Ward (1989) - Holotype (unique syntype) worker, Corumba, Matta Grosso [do Sui], Brazil, 15.viii.1900, (Museo Civico di Storia Naturale, Genoa) [Examined].
Pseudomyrma culmicola Holotype (unique syntype) worker, Trinidad (Forel) (Musee d'Histoire Naturelle Genève) [Examined].
- Emery, C. 1906c . Studi sulle formiche della fauna neotropica. XXVI. Bull. Soc. Entomol. Ital. 37: 107-194 (page 119, worker described)
- Kempf, W. W. 1972b. Catálogo abreviado das formigas da regia~o Neotropical. Stud. Entomol. 15: 3-344 (page 224, Combination in Pseudomyrmex)
- Ward, P. S. 1989a. Systematic studies on pseudomyrmecine ants: revision of the Pseudomyrmex oculatus and P. subtilissimus species groups, with taxonomic comments on other species. Quaest. Entomol. 25: 393-468 (page 432, Raised to species, and senior synonym of culmicola)
- Wheeler, G. C.; Wheeler, J. 1973d. Supplementary studies on ant larvae: Cerapachyinae, Pseudomyrmecinae and Myrmicinae. Psyche (Camb.) 80: 204-211 (page 207, larva described)