Marine tardigrades (Heterotardigrada) from Senghor Seamount, Eastern Tropical Atlantic, with the description of two new species from the taxon Stygarctidae

The Atlantic Ocean’s seamounts are known for their high diversity of meiofauna. In this study an overview of the marine tardigrade fauna on the yet not studied Senghor Seamount is presented. The materials were collected during the M79/3 cruise of R/V Meteor in the Cabo Verde (Cape Verde) region from Senghor Seamount and a deep-sea reference site. Samples from the seamount yielded 20 taxa: three determined species ( Chrysoarctus briandi , Quisarctus armatus , Raiarctus colurus ), 15 other taxa ( Angursa sp., Batillipes sp., Halechiniscidae sp., Halechiniscidae gen. A sp. A, Chrysoarctus sp., Dipodarctus aff. subterraneus , Dipodarctus sp., Florarctinae sp., Halechiniscus cf. perfectus , Halechiniscus sp., Styraconyxidae sp., Raiarctus aff. variabilis , Raiarctus sp., Tanarctus sp., Tholoarctus cf. natans natans), and two new species, for which we provide morphological descriptions: Megastygarctides hekatae sp. nov . with rare genital spines; and Parastygarctus potercha sp. nov . with a paedomorphic appearance. In contrast, the deep-sea reference station is represented only by two taxa ( Angursa abyssalis and Angursa sp.). This observation supports the hypothesis of seamounts as hotspot habitats for marine tardigrades.