Diversity of oceanic anglerfishes (Lophiiformes: Ceratioidei) collected off the Amazon River mouth, including four new records in Brazilian waters

Abstract The oceanic anglerfishes (Lophiiformes: Ceratioidei) are among the most diverse and ecologically distinctive groups of deep-sea fishes, exhibiting some of the most extreme morphological adaptations in the marine realm. Despite their remarkable biological traits, they remain among the most understudied vertebrates globally, primarily due to the logistical challenges associated with accessing their natural habitats. Here we report the diversity of oceanic anglerfishes collected during the AMAZOMIX scientific cruise, conducted in 2021 off northern Brazil, including the Amazon River plume, across depths ranging from the surface to approximately 1200 m. A total of 34 ceratioid specimens, representing six families and eight genera, were collected. Seven species were identified: Melanocetus johnsonii (Melanocetidae), Haplophryne mollis (Linophrynidae), Lophodolos acanthognathus, Oneirodes carlsbergi (Oneirodidae), Centrophryne spinulosa (Centrophrynidae), Gigantactis vanhoeffeni and Rhynchactis leptonema (Gigantactinidae). Haplophryne mollis, L. acanthognathus, C. spinulosa , and R. leptonema are reported for the first time in Brazilian waters. This study provides morphological and distributional remarks for all identified species and presents an updated checklist of deep-sea anglerfishes recorded in Brazilian waters.