Overcoming taxonomic, phylogenetic and biogeographic shorfalls in Tardigrada: an integrated view in a neglected meiofauna group

Abstract

Tardigrades are free-living micrometazoans measuring 50 µm to 1mm, known since the XVII century. About 1.200 species are widely distributed in marine and terrestrial environments biomes but distribution patterns are considered poorly known. Some studies suggest a future description of at least a double of species registered nowadays. Lacks of information on this group reflect in actual status of biodiversity of tardigrades in Brazil: registered marine species are from few beaches in northeast coast and southeast coast of Brazil, while registered limnoterrestrial species are punctual, antique and incomplete. Some of few species described in Brazil are ubiquitous but probably due to identifying problems and taxa delimitation through traditional morphology studies. Despite their importance, those studies have not been sufficient to answer taxonomic and biogeographic questions. These problems are related to Linnean, Wallacean and Darwinian shortfalls, three of seven global biodiversity access shortfalls. In amplifying sample points of tardigrades in Brazil using integrative morphology (light microscopy differential interference contrast, Scanning electron microscopy, Transmission electron microscopy and confocal microscopy) and molecular investigation techniques, this research tries to solve problems of species delimitation, morphological character study, and certainly improve the knowledge about distribution, diversity, and classification of these tiny animals (AU)