Spider ants of the genus Leptomyrmex Mayr (Hymenoptera: Formicidae: Dolichoderinae) are conspicuous species of Australasian rainforests, with putative fossil relatives in the Neotropics and Europe. There is longstanding debate over the biogeographical history of the genus, with the Palaearctic and Neotropical regions proposed as alternate centres of origin. We propose a resolution of this debate with the recent discovery and analysis of an extant species from central Brazil, L. relictus sp.n., which we describe from workers, males and brood. We sequence ten nuclear genes in the new species and in several Australian Leptomyrmex species, and append these data to a 54-taxon, 10-gene data matrix previously generated for the subfamily Dolichoderinae. We conduct phylogenetic and divergence dating analyses, and re-evaluate the fossil record of the group. We recover Leptomyrmex relictus sp.n. as a member of the Leptomyrmex clade with high support. It is sister to the Australasian species, and the genus Leptomyrmex is, in turn, sister to a pair of Neotropical genera, Forelius and Dorymyrmex. We infer a Neotropical origin for the genus and estimate a mid-Eocene (46 Ma, 95% CI 56 to 36 Ma) origin for the crown genus and an Oligocene origin for the Australasian clade (29 Ma, 95% CI 40 to 19 Ma). We confirm placement of the Dominican amber species †L. neotropicus Baroni Urbani in the genus but reject a close relationship with the Palaearctic fossil taxa †Leptomyrmula Emery and †Usomyrma Dlussky, Radchenko & Dubovikoff, considering them incertae sedis in the subfamily (Dolichoderinae). In contrast to the mesophilic preferences of the Australasian species of Leptomyrmex, the new Brazilian species inhabits cerrado (dry savannah). Our results support a Neotropical origin for spider ants with dispersal to Australia. Rafting on west-bound currents and/or a historical diversity imbalance between Australia and South America are proposed as alternate hypotheses to explain a pattern of biased E-W mid-Tertiary dispersal for ants with austral distributions. This pattern is suggested by our results in conjunction with observations of other ant clades. Overall, our findings highlight the value of integrated taxonomy, critical interpretation of morphology, and a comparative phylogenetic framework when conducting palaeontological and biogeographical studies of insect species. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid: zoobank.org:pub

Ants, an ecologically successful and numerically dominant group of animals, play key ecological roles as soil engineers, predators, nutrient recyclers, and regulators of plant growth and reproduction in most terrestrial ecosystems. Further, ants are widely used as bioindicators of the ecological impact of land use. We gathered information of ant species in the Atlantic Forest of South America. The ATLANTIC ANTS data set, which is part of the ATLANTIC SERIES data papers, is a compilation of ant records from collections (18,713 records), unpublished data (29,651 records), and published sources (106,910 records; 1,059 references), including papers, theses, dissertations, and book chapters published from 1886 to 2020. In total, the data set contains 153,818 ant records from 7,636 study locations in the Atlantic Forest, representing 10 subfamilies, 99 genera, 1,114 ant species identified with updated taxonomic certainty, and 2,235 morphospecies codes. Our data set reflects the heterogeneity in ant records, which include ants sampled at the beginning of the taxonomic history of myrmecology (the 19th and 20th centuries) and more recent ant surveys designed to address specific questions in ecology and biology. The data set can be used by researchers to develop strategies to deal with different macroecological and region‐wide questions, focusing on assemblages, species occurrences, and distribution patterns. Furthermore, the data can be used to assess the consequences of changes in land use in the Atlantic Forest on different ecological processes. No copyright restrictions apply to the use of this data set, but we request that authors cite this data paper when using these data in publications or teaching events.

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SciELO Books / SciELO Livros / SciELO Libros BRANDÃO, CRF., et al. Dieta das Poneromorfas Neotropicais. In: DELABIE, JHC., et al., orgs. As formigas poneromorfas do Brasil [online]. Ilhéus, BA: Editus, 2015, pp. 145-161. ISBN 978-85-7455-441-9. Available from SciELO Books . All the contents of this work, except where otherwise noted, is licensed under a Creative Commons Attribution 4.0 International license. Todo o conteúdo deste trabalho, exceto quando houver ressalva, é publicado sob a licença Creative Commons Atribição 4.0. Todo el contenido de esta obra, excepto donde se indique lo contrario, está bajo licencia de la licencia Creative Commons Reconocimento 4.0.

Ants of the genus Basiceros Schulz, 1906 are elusive species known only from Neotropical rainforests. Little information is available regarding their natural history, and nothing is known about the phylogenetic relationships among species within the genus. The genus has been the subject of some controversy regarding generic delimitation but is currently a member of the ‘Basiceros-genus group’ following recent classification changes. For mouthparts, labral and mandibular morphologies present considerable variation in the Basiceros-genus group, likely a result of adaptive evolution. In Basiceros, those differences can be observed in the labrum shape and the various degrees of development of the labral cleft and the clypeomandibular space. Here, in an attempt to illuminate the evolution of the group, species boundaries are tested for Basiceros. The evolutionary relationships of its species are investigated using molecular and morphological data. Bayesian inference and maximum likelihood analyses of a molecular dataset consisting of up to nine genes (three mitochondrial, six nuclear) and including samples from multiple populations of all known Basiceros taxa recovered the monophyly of the genus and of its species, with two well-resolved internal clades: the singularis clade and the disciger clade. Focusing on the female castes of Basiceros, an ancestral state reconstruction is presented for mandibles and labrum morphology. The results suggest that the labrum and clypeomandibular morphologies are highly labile, although phylogenetically important characters in the genus. Mouthpart traits indicate a strong correlated evolutionary history potentially associated with specialized feeding habits.

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The ant genus Basiceros is an exclusively Neotropical group known for its cryptic habits. Based on a recent molecular phylogenetic framework, a comprehensive revisionary study of the genus is presented. Nine species are recognized, two of which are described as new (Basiceros browni sp. nov. and Basiceros tumucumaquensis sp. nov.). Basiceros redux (Donisthorpe 1939) is transferred to the genus Octostruma (O. reducta comb. nov.). As part of this revisionary work, taxonomic keys and images to all species and castes are provided. Castes and sexes (including larvae, males, and intercastes) are described for the first time for several Basiceros species. New records considerably expand the distributional range for most species. Natural history data and comments on character plasticity and convergence are also included.

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