Material examined 7 preserved specimens with register number (included station): 124131-B79 (B11 V 05);124131- B80 (B11 V 08); 124131-B81 (B11 V 10).
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Diagnostic characters. Arms 5 and thin membrane with muscle fibre and fleshy bands and also spiraculaes (Fig. 3a). With 6 paxillar spines and 5 spines forming a wreath around the anus (Fig. 3b). Two oral spines and 2 suboral ones (Fig. 3c). With 2 rows of tubefeet, 2 adambulacral spines (Fig. 3d).
Distribution. Atlantic Ocean, west of Ireland, between Azores and Portugal, north east of Newfoundland, Caribbean Sea, Cuba, Jamaica (Perrier, 1894; Mortensen 1927; Clark & Downey 1992; Mah, 2022; Obis, 2022).
Bathymetric range. 1900 m (Mortensen 1927)– 4330 m (MNHN-IE-2019-5917 identified by Sibuet). Present study. 1565 – 1720 m.
Remarks. Fifty-two species of Hymenaster Wyville Thomson, 1873 have been described. Five of them are present in the study area: Hymenaster giboryi, Hymenaster. pellucidus Thomson, 1873, Hymenaster rex Perrier, 1885, Hymenaster reticulatus Sibuet, 1976 and Hymenaster tenuispinus Sibuet, 1976. Hymenaster giboryi and H. pellucidus present 2 or 3 adambulacral spines while the rest varies in that number but always present more than two. In addition, they differ in the paxillar spines numbers, H. giboryi has 6 and H. pellucidus range from 2 to 5 (Clark & Downey, 1992).