Background: Ants (Insecta, Hymenoptera, Formicidae) are social insects and one of the most abundant groups of animals. Their colonies are established in a wide range of habitats, such as in cavities in the ground, litter on the forest floor or in rocky cracks. Currently, there are approximately 15,000 valid species of ants, of which about 6,000 are recorded from the Neotropical Region. The Atlantic Forest is one of the biomes with the greatest biodiversity, showing a high degree of endemism. However, it has suffered severe impacts and is now reduced to a fraction of the original area. One of the most significant remnants of the Atlantic Forest is the Parque Nacional da Tijuca (PNT), a protected area located in the state of Rio de Janeiro, Brazil. There is limited knowledge about the myrmecofauna of the PNT, with most research efforts focused on the Serra da Carioca sector.

New information: In the present study, we performed the first inventory of the mirmecofauna of the Floresta da Tijuca sector of the PNT, using pitfall traps and Winkler extractors in areas with three different degrees of preservation. In total, 80 species are recorded from Floresta da Tijuca, of which 18 are reported for the first time from this sector, 37 from the PNT, 10 from the State of Rio de Janeiro and one from the Atlantic Forest biome. These results increase the known diversity of ants of the PNT from 149 to 200 species. Furthermore, the known geographic distribution of Hypoponeraviri (Santschi, 1923) is extended northwards, those of Holcoponeramina Brown, 1956 and Neocerapachysneotropicus Weber, 1939, southwards and Brachymyrmexbruchi Forel, 1912 and Hypoponeraparva (Forel, 1909), eastwards. The most abundant species in our samples was Holcoponeramoelleri (Forel, 1912), followed by Pachycondylastriata F. Smith, 1858, Strumigenysdenticulata Mayr, 1887, Hypoponeratrigona (Mayr, 1887), Megalomyrmexgoeldii Forel, 1912 and Hylomyrmareitteri (Mayr, 1887). The primary forest area was the richest, followed by the disturbed and advanced restoration areas. The species richness was higher in the primary forest and advanced restoration areas during the dry season, while it was higher in the disturbed area during the rainy season.

Márcio Morais Silva, Antônio J. Mayhé Nunes, Felipe F. F. Moreira.