First confirmed record of the starfish family Paulasteriidae (Asteroidea: Forcipulatida) in the Atlantic Ocean

Abstract Hydrothermal vents are known to host unique faunal assemblages supported by chemosynthetic production; however, the fauna associated with inactive sulphide ecosystems remain largely uncharacterised across the global seafloor. In November 2023, a six-rayed starfish was collected from the Semenov hydrothermal field on the Mid-Atlantic Ridge. A combination of morphological and molecular methods has confirmed the identity of this species as Paulasterias mcclaini Mah et al. 2015 (Forcipulatida: Paulasteriidae), providing the first validated record of this family in the Atlantic Ocean. We present an updated morphological description of the species, alongside phylogenetic analysis of the COI, 16S, 12S, and H3 genetic markers. The biogeography of the family is discussed, and previously published records amended.