The Deep-Sea Genus <i>Coronarctus</i> (Tardigrada, Arthrotardigrada) in Brazil, South-Western Atlantic Ocean, with the Description of Three New Species

Abstract

Three new marine tardigrade species from the deep-sea genus Coronarctus are described from the South-Western Atlantic Ocean: Coronarctus dissimilis sp. nov., C. neptunus sp. nov., and C. yurupari sp. nov. These, and C. laubieri Renaud-Mornant, 1987, are the first records of deep-sea tardigrades from this marine region. Specimens of those species were collected from two localities of the Brazilian continental slope (Potiguar and Campos basins) at depths comprised between 150 and 3000 m. Specimens of the three new species have short cephalic appendages and heteromorphic claws, belonging to the, here designated, C. tenellus group of species. Each of the new species can be distinguished from all the other species of the group by their peculiar-shaped secondary clavae and claws. The most relevant morphological characters used for the taxonomy of the genus: shape of cephalic cirri, shape of secondary-clavae, size and number of accessory spines on claws, and shape of seminal receptacles, are discussed and an identification key to all ten known Coronarctus species is provided.

Keywords

• abyssal
• continental slope
• <i>coronarctus dissimilis</i> sp. nov.
• <i>c. neptunus</i> sp. nov.
• <i>c. yurupari</i> sp. nov.
• identification key
• meiofauna
• taxonomy