Traumatomutilla is a diverse genus of Neotropical velvet ants (Mutillidae). Here we revise the T. americana species group, recognizing three species. Mutilla dubia Fabricius, 1804, M. simulans Smith, 1855, M. albata Smith, 1879, and M. obsoleta (Klug, 1821) are proposed as junior synonyms of Traumatomutilla americana (Linnaeus, 1758). Traumatomutilla maula Casal, 1969, Ephuta punctosignata André, 1906, Mutilla latevittata Cresson, 1902, and M. oculifera Smith, 1855 are proposed as junior synonyms of Traumatomutilla quadrum (Klug, 1821). Mutilla acara Cresson, 1902, M. polita Smith, 1855, M. gemina Gerstaecker, 1874, M. trinacria Gerstaecker, 1874, M. lasiogastra Burmeister, 1875, and M. cuyana Burmeister, 1875 are proposed as junior synonyms of Traumatomutilla ocellaris (Klug, 1821). Traumatomutilla bellifera (Gerstaecker, 1874) is transferred to the T. trochanterata species-group; T. lunigera (Gerstaecker, 1874) and T. compar (André, 1898) are transferred to the T. inermis species-group. Both sexes are redescribed for all species. Notes on the biology and host association for T. ocellaris are provided. Finally, identification keys to the species and color forms of the T. americana group are provided.

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which is part of the ATLANTIC SERIES data papers, is a compilation of ant records from collections (18,713 records), unpublished data (29,651 records), and published sources (106,910 records; 1,059 references), including papers, theses, dissertations, and book chapters published from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.

Dynamic signals are a widespread phenomenon in several taxa, usually associated with intraspecific communication. In contrast, dynamic iridescent signals are detectable only at specific angles of illumination; hence, the animal can hide the signal to avoid detection when necessary. This structural coloration is mostly dependent on the illumination, the contrast against the background and the vision of the receiver. Complex behavioural displays can be coupled with structural coloration to create dynamic visual signals that enhance these functions. Here, we address whether iridescence of the males of a damselfly that inhabits dark rainforests, Chalcopteryx scintillans, can be considered a dynamic visual signal. We analyse whether coloration is perceived by conspecifics, while reducing detectability to eavesdroppers against three types of backgrounds. Our results suggest that the visual background affects the detectability of male hindwings by different receivers, mostly predators and prey. We discuss whether these results and the angle dependence of colour could indicate a mechanism to avoid unwanted intraspecific interactions or even to lure both predators and prey. We conclude that the main functions of the dynamic iridescent signal are to communicate with conspecifics while hindering the signal for prey, adding evidence of the multifunctionality of structural coloration coupled with behavioural displays in animals.