Tapinoma ramulorum

I have taken this species frequently at San Jose, Costa Rica, nesting in dry twigs of various trees. Emery's specimens were found in the same locality in dry twigs of the "tuete" (Vernonia brachiata Bentham). Wheeler (1934)

Identification
Scapes of variable length, extending beyond margin of vertex but never a third their length; in full face view, margin of vertex medially emarginate; gaster the same color as mesosoma and head or darker; nests in live or dead plant cavities (Jack Longino).

Distribution based on Regional Taxon Lists
Neotropical Region: Colombia, Costa Rica, Trinidad and Tobago.

Biology
Jack Longino: This is the most abundant species in vegetated habitats of Costa Rica. It occurs in most habitats, from sea level to middle elevations. Nests are in almost any kind of preformed plant cavity, but the chambers are usually very small and may not be sharply bounded. Nests can occur in tiny dead twigs (down to 5mm outside diameter, 3mm inside diameter), larger dead branches, under bits of loose bark, in cavities in live stems, under and in epiphyte mats, in the bases of bromeliads, and sometimes in myrmecophytes. Tapinoma ramulorum may be found nesting close to other ant nests. For example, a dead branch with a Camponotus nest in the center may have a T. ramulorum nest under the loose bark or bits of rotten wood on the surface of the branch. Colonies are often polygynous.

Nomenclature

 *  ramulorum. Tapinoma ramulorum Emery, 1896g: 101 (w.q.m.) COSTA RICA. Current subspecies: nominal plus annellatum, inrectum, saga, satullum, toltecum. See also: Wheeler, W.M. 1934g: 178.

Taxonomic Notes
Emery described this species as having scape surpassing occiput by one to one and a half times diameter. I am using this name to hold a large number of specimens that exhibit what seems like too much variation to be intraspecific. But at this point I cannot make any further distinctions. The variation is in scape length and color, and this variation is also reflected in the queens (Jack Longino).

References based on Global Ant Biodiversity Informatics

 * Baroni Urbani C. 1977. Katalog der Typen von Formicidae (Hymenoptera) der Sammlung des Naturhistorischen Museums Basel (2. Teil). Mitt. Entomol. Ges. Basel (n.s.) 27: 61-102.
 * Dattilo W. et al. 2019. MEXICO ANTS: incidence and abundance along the Nearctic-Neotropical interface. Ecology https://doi.org/10.1002/ecy.2944
 * Emery C. 1896. Studi sulle formiche della fauna neotropica. XVII-XXV. Bullettino della Società Entomologica Italiana 28: 33-107.
 * Emery C. 1913. Hymenoptera. Fam. Formicidae. Subfam. Dolichoderinae. Genera Insectorum 137: 1-50.
 * Fernández, F. and S. Sendoya. 2004. Lista de las hormigas neotropicales. Biota Colombiana Volume 5, Number 1.
 * INBio Collection (via Gbif)
 * Kempf, W.W. 1972. Catalago abreviado das formigas da regiao Neotropical (Hym. Formicidae) Studia Entomologica 15(1-4).
 * Mirmecofauna de la reserva ecologica de San Felipe Bacalar
 * Varela-Hernandez, F., M. Rocha-Ortega, R. W. Jones, and W. P. Mackay. 2016. Insectos: Hormigas (Formicidae) del estado de Queretaro, Mexico. Pages 397-404 in W. Jones., and V. Serrano-Cardenas, editors. Historia Natural de Queretaro. Universidad Autonoma de Queretaro, Mexico.