Deep-sea Echinoids from the Galician Bank (North Atlantic Ocean)

The Galician Bank (GB) is a seamount in the Northeast Atlantic Ocean (Northwest Spain) at 180 km from the Galician coast. Its summit is between 650 and 1500 m below the surface as it rises from the abyssal plain at 4000 m depth. The dynamics of water masses and the geomorphology of the area favour the retention of nutrients and larvae, augmenting the diversity of benthic communities. The present study aims to inventory and reviewing of the echinoid fauna collected during the LIFE+ INDEMARES project carried out on the Galician Bank. New findings are compared with previous studies of the Official Spanish Checklist (IEEM: "Inventario Español de Especies Marinas", 2017, 2020) to update our knowledge of the diversity and distribution of echinoid species in the study region. During the surveys carried out under the auspices of project LIFE+INDEMARES on the Galician Bank (2010-2011), a total of 139 echinoids belonging to 8 different species were sampled from 27 stations, between 744 and 1764 m depth. The most frequently collected species were Cidaris cidaris (Linnaeus, 1758) and Sperosoma grimaldii Koehler, 1897. After public datasets analysis, it turns out that one species should be considered as a new record in Spanish waters: Echinocyamus grandiporus Mortensen, 1907, and two for the North Atlantic Spanish Marine Sub-Division: Holanthus expergitus (Loven, 1871) and Plexechinus hirsutus Mortensen, 1905. In addition, the bathymetric range of Echinocyamus pusillus (O.F. Müller, 1776) was extended to 1313 m depth.