Assessment of larval diversity of Brachyura (Crustacea, Decapoda) on the southeast coast of Brazil using DNA metabarcoding

Abstract

Assessing marine planktonic communities regarding their biodiversity and taxonomic composition is essential for environmental monitoring and species conservation, especially in a global climate change scenario, in which many species will become extinct before they are described. An important component of marine zooplankton are crustacean larvae, especially those belonging to the Infraorder Brachyura (i.e., crabs), since it is the most diverse. The characterization of crab larval biodiversity is traditionally performed through the morphological identification of the different stages of development. However, due to the difficulty of culturing the organisms in the laboratory, there are still many gaps in larval descriptions. The use of DNA barcoding allowed the identification of specimens to the species level by sequencing short standardized DNA fragments. However, the technique is limited to identifying one organism at a time. DNA metabarcoding enables simultaneous identification of many taxa within the same sample based on high-throughput sequencing of pooled genomic DNA. In this work we will use DNA metabarcoding to evaluate the larval diversity of Brachyura, in southeastern Brazil, an important region of faunal transition (faunas of the southern and northern hemispheres) and with high biodiversity. We hope to evaluate the hypothesis of an underestimated diversity and, as a consequence, complement the species inventory by identifying new native crab species to the region, evaluating possible patterns of distribution and species richness among the sample locations and possibly registering the presence of new invasive species.