Preliminary in situ observations of the archibenthal megafauna on the continental slope of the Atacama Trench off Peninsula de Mejillones, Northern Chile

The deep-sea fauna of the southeastern Pacific remains vastly understudied, particularly along the northern coast of Chile, a transitional zone influenced by both Peruvian and subtropical ecosystems. During the Schmidt Ocean Institute's FKT240425 expedition aboard the R/V Falkor (too), conducted systematic deep-sea ROV surveys between 1816 and 4504 m depth off the Peninsula de Mejillones, Chile. The study reports new in situ records and significant range extensions for about one hundred species. A total of 79 macroinvertebrate samples were collected using the ROV SuBastian. The preliminary analysis of groups such as Arthropoda, Echinodermata, Decapoda, Mollusca, and Porifera indicates the potential presence of at least 35 new species. The preliminary conclusions of the observed and collected material are presented here, with comments about the taxonomic status of each one. Thus, this research cruise has contributed the most up-to-date records to the biodiversity of the Atacama Trench.