Heart urchins from the depths: Corparva lyrida gen. et sp. nov. (Palaeotropidae), and new records for the southwestern Atlantic Ocean

Introduction: Sea urchins in the order Spatangoida are most diverse group of extant echinoids. Objective: Describe a new genus and species from abyssal depths, add records for known species. Methods: Specimens were collected during several cruises at different areas southwestern Atlantic Ocean (SWAO), among 37-55° S latitude depths ranging 55 to 3 000 m. We present morphological ultrastructure analyses. Results: Corparva lyrida gen. et sp. nov. (Palaeotropidae) is described Mar del Plata Canyon on Argentine continental slope (2 950 m depth), first record this family Argentina. differs having an apical system semi-ethmolytic, labrum reaching rear part second adjacent ambulacral plate. also report northernmost distribution deepest Brisaster moseleyi (38° latitude, 2 212 northward extension range Tripylus excavatus (39° 74 Abatus philippii agassizii Burdwood Bank/MPA Namuncurá. Conclusions: The work brings novel updated data about diversity spatangoids SWAO, including description C. nov., This shows how much remains be heart especially deep-sea.