Further record of the deep-sea euphausiid, Thysanopoda cristata G. O. Sars, 1883 (Euphausiacea, Euphausiidae) from the southwestern Atlantic: with comments on morphological variations

Abstract

Euphausiids are a diverse order of crustaceans that play a key role in pelagic food webs. The genus Thysanopoda H. Milne Edwards, 1830 is composed of 14 valid species, widely distributed in all oceans. However, some gaps remain in our knowledge of the geographic distribution of Thysanopoda cristata G. O. Sars, 1883, and its actual occurrence in Brazil. This study aims to expand the knowledge on krill diversity in Brazilian waters, confirming the occurrence of T. cristata and providing illustrations of its morphological variations. Four specimens, two males and two females, were collected on board R/V “Antea” in October 2015, using a micronekton net with 1 mm mesh size, at depths ranging between 10 and 1660 m. Before this study, reports of T. cristata from Brazil were provided only in species lists or unpublished data. Our study confirms the presence of the species from the southwestern Atlantic and brings new information on its morphology.