Morphological, molecular and phylogenetic characterization of a new Chloeia (Annelida: Amphinomidae) from a pockmark field

Abstract

Pockmarks are crater-like depressions in seabed sediments commonly found along continental margins and generally associated with episodic fluid seepage. In this study, we describe a new species of Chloeia (Amphinomidae) gathered from a pockmark field, located off the southeastern Brazilian continental margin (~750 m depth), SW Atlantic. The complete mitochondrial genome is given, together with a multi-gene phylogenetic analysis including our new species and other amphinomids. The new species is similar to Chloeia bimaculata, C. violacea and C. kudenovi in having the longest neuropodial cirri on the second chaetiger. Chloeia pocicola sp. nov. differs from these congeners mainly by the combination of its dorsal pigmentation pattern, eyes, notopodial cirri, and neuropodial chaetae. Our phylogenetic hypothesis suggests Chloeia as a sister group of Archinome, which departs from previous studies, that instead suggests the clade Chloeia-Notopygos. This study increases our knowledge on the biodiversity of deep-sea pockmark environments, and contribute to the systematics of Amphinomidae, which is generally well represented in shallow waters, but also occurs in deep waters, including chemosynthetic environments.