Even though Colombia has high levels of ant species richness in the Neotropical region, this richness continues to increase. New records of the ant subfamilies Amblyoponinae, Dolichoderinae, Dorylinae, Myrmicinae, and Ponerinae are presented. Two species of Fulakora, two species of Azteca, one species of Cylindromyrmex, 25 species of Myrmicinae belonging to 12 genera (Acanthognathus, Basiceros, Daceton, Eurhopalothrix, Hylomyrma, Mycetomoellerius, Mycetophylax, Mycocepurus, Octostruma, Pheidole, Rogeria, and Talaridris), and one species of Leptogenys are registered for the first time for Colombia. Five species are new records for South America. For each species, the geographical distance of the record closest to the Colombian locality is offered. Several factors, such as access to previously unexplored conserved areas, sampling techniques that cover heterogeneous microhabitats such as leaf litter, and many more taxonomic researches have allowed the knowledge of ant fauna in Colombia to continue growing.

Typhlomyrmex Mayr is a genus of small and cryptic ants of the subfamily Ectatomminae. Here, we provide taxonomic notes on the ants of the genus Typhlomyrmex Mayr from Colombia, along with the description of Typhlomyrmex encantosp. nov. based on the worker caste, and the re-description / description of the worker caste of T. clavicornis Emery and T. prolatus Brown. Finally, we offer a key for the known species of Typhlomyrmex, and distribution maps for the three species this study focuses on.

The Galápagos ant fauna has long been understudied, with the last taxonomic summary being published almost a century ago. Here, we provide a comprehensive and updated overview of the known ant species of the Galápagos Islands with updated species distributions. The list is based on an extensive review of literature, the identification of more than 382,023 specimens deposited in different entomological collections, as well as recent expeditions to the islands. The fauna is composed of five subfamilies (Dolichoderinae, Dorilynae, Formicinae, Myrmicinae and Ponerinae), 22 genera and 53 species, though 3 of these species are considered dubious records. Finally, we provide an illustrated identification key of the species in the archipelago.

Worker specialization extends the behavioral and ecological repertoire of ant colonies. Specialization may relate to colony defense, brood care, foraging, and, in some taxa, storage. Replete workers swell the crop and gaster to store liquid food, which can be accessed by other colony members through trophallaxis. This storage ability, known as repletism, has independently evolved across several ant lineages, but the temporal history of this trait has not yet been investigated. Here, we describe the first fossil replete in the extinct species Leptomyrmex neotropicus Baroni Urbani, 1980 preserved in Miocene-age Dominican amber. Together with new evidence of repletism in L. neotropicus' extant sister species, L. relictus Boudinot et al., 2016, we reconstruct the pattern of acquisition and descent in this storage-linked trait. Our ancestral state reconstruction suggests that Leptomyrmex acquired replete workers in the Eocene and may therefore represent the earliest instance of so-called honeypot ants among all known ants, both living and extinct.

The genus Metopiellus (Staphylinidae, Pselaphinae) is confirmed in Colombia with the description of Metopiellus guananosp. nov. from the northern Amazon. Major diagnostic characters, a distributional map, and ecological data are given. Finally, a previous taxonomic key to Metopiellus is updated to include the new species.

Background Ponerine ants are almost exclusively predatory and comprise many of the largest known ant species. Within this clade, the genus Neoponera is among the most conspicuous Neotropical predators. We describe the first fossil member of this lineage: a worker preserved in Miocene-age Dominican amber from Hispaniola. Results Neoponera vejestoria sp. nov. demonstrates a clear case of local extinction—there are no known extant Neoponera species in the Greater Antilles. The species is attributable to an extant and well-defined species group in the genus, which suggests the group is older than previously estimated. Through CT scan reconstruction and linear morphometrics, we reconstruct the morphospace of extant and fossil ants to evaluate the history and evolution of predatory taxa in this island system. Conclusions The fossil attests to a shift in insular ecological community structure since the Miocene. The largest predatory taxa have undergone extinction on the island, but their extant relatives persist throughout the Neotropics. Neoponera vejestoria sp. nov. is larger than all other predatory ant workers known from Hispaniola, extant or extinct. Our results empirically demonstrate the loss of a functional niche associated with body size, which is a trait long hypothesized to be related to extinction risk.

A new species of Eurhopalothrix Brown & Kempf, E. amati Fiorentino, Tocora and Fernández, n. sp. is described based on workers collected in northwestern Colombia. A taxonomic key and distributional map for the new species in the country are provided. This new species differs from other Eurhopalothrix ants by the configuration of specialized setation, a decrease in its propodeal spines, its irregular metanotum profile, and the triangular shape of the head capsule.

An overview of the order Strepsiptera in Colombia is provided. The family Halictophagidae is recorded for the first time based on a female parasitizing a treehopper Ceresini (Membracidae). Strichotrema beckeri is a new record for the country. The ant genus Megalomyrmex is documented as a new host for Caenocholax fenyesi. A short review of the ants parasitized by Strepsiptera in the Neotropics is presented. Currently, the order in Colombia is known for the families Halictophagidae, Myrmecolacidae and Stylopidae.