Ants of Brazil: an overview based on 50 years of diversity studies

Despite the historical efforts to list and organize the taxonomic knowledge about the Brazilian ant fauna, the most diverse in the world, several gaps regarding species distribution data and sampling coverage persist. In an attempt to fill some of these gaps, we here apply a scientometric approach to provide an updated overview of the ants of Brazil based on formal publications on ant diversity in the Brazilian territory. In the last 50 years, ant diversity studies in Brazil revealed 1130 species, corresponding to around 70% of the species known to occur in the country. The Brazilian biomes with the highest number of described species recorded were, respectively, the Amazon Forest (716 species), Atlantic Forest (657 species), Cerrado (389 species), Caatinga (185 species), Pantanal (143 species), and Pampa (86 species). Considering the number and frequency of unidentified species, the genera Azteca, Hypoponera, Pheidole, and Solenopsis represent the main knowledge frontiers regarding taxonomic resolution, with more than 80% of their records associated with morphospecies codes in diversity studies in Brazil. Moreover, around 7.5% of the papers presented inconsistences in their species lists regarding the validity of taxonomic names, and we found studies for which some taxa records are geographically implausible. Besides demonstrating the importance of ecological publications to the ant diversity knowledge in Brazil, our findings highlight a strong sampling bias in ant occurrence data in the country, with species records unevenly distributed across Brazilian biomes. In short, our results constitute valuable information for future projects on ant taxonomy and surveying in Brazilian natural areas.

尽管既往已有诸多研究致力于整理编目全球物种多样性最为丰富的巴西蚁类区系分类学知识，但目前关于巴西蚁类的物种分布数据与采样覆盖范围仍存在诸多空白。为填补其中部分空白，本文基于巴西境内蚁类多样性的正式发表文献，采用文献计量学方法对巴西蚁类进行了最新综述。近50年来，巴西境内开展的蚁类多样性研究已记录到1130个物种，约占该国已知蚁类物种总数的70%。已记录描述物种数量最多的巴西生物群系依次为：亚马逊雨林（716种）、大西洋森林（657种）、塞拉多（389种）、卡廷加（185种）、潘塔纳尔湿地（143种）以及潘帕斯草原（86种）。从未鉴定物种的数量与出现频率来看，阿兹特克蚁属（Azteca）、猛蚁属（Hypoponera）、大头蚁属（Pheidole）以及火蚁属（Solenopsis）是当前分类学分辨率方面的主要研究空白领域——在巴西的蚁类多样性研究中，上述类群超过80%的记录均以形态种（morphospecies）编码形式存在。此外，约7.5%的发表文献在物种名录的分类学名称有效性方面存在不一致问题，部分研究的类群记录还存在地理分布不合理的情况。本研究不仅明确了生态学文献对巴西蚁类多样性研究的重要价值，同时也揭示了该国蚁类出现数据存在显著的采样偏差，物种记录在巴西各生物群系间的分布极不均衡。简言之，本研究结果可为未来巴西自然区域内的蚁类分类学研究与野外调查项目提供重要参考依据。