On the presence of Ocnus planci Brandt, 1935 (Echinodermata: Dendrochirotida: Cucumariidae) in the Mostaganem region (Western Algerian coast).

In Algeria, few studies have been carried on the Holothuriodea especially the family Cucumariidae Ludwig, 1894. A specimen was caught as bycatch from a commercial benthic trawler on the Mostaganem coast (northwest of Algeria). Based on a detailed study of the morphological, anatomical and endoskeletal characters, this specimen is confirmed to be Ocnus planci (Brandt, 1835).

Morphological distinction of the Ophioderma Müller & Troschel, 1840 species (Echinodermata: Ophiuroidea: Ophiacanthida: Ophiodermatidae) from the Algerian west coast.

Ophioderma longicaudum (Bruzelius, 1805) is a very common brittlestar in the Mediterranean Sea that had been considered as a complex of cryptic species since 2009. Recently, five species were separated from this complex, but they remain morphologically very close. The aim of this study is to attempt for the first time to identify the species of Ophioderma found at the Algerian west coast, using morphological and morphometric analysis.

First record of Luidia atlantidea Madsen, 1950 (Echinodermata: Asteroidea: Paxillosida: Luidiidae) in the Sidi-Medjdoub areaMostaganem (West Algerian coast, Mediterranean Sea).

The genus Luidia is currently represented in the Mediterranean Sea by three species, namely Luidia ciliaris (Philippi, 1837), Luidia sarsii sarsii (Dben Koren in Dben, 1844) and Luidia atlantidea (Madsen, 1950) which is an Atlantic species recently reported from the Spanish and Tunisian coasts. Two individuals of Luidia atlantidea were collected as bycatch from small-scale fisheries in the region of Sidi-Medjdoub (Mostaganem, Algeria) at a depth of 53 m. The detailed study of the morphological and anatomical characters allowed us to formally identify the two individuals of Luidia atlantidea and therefore to report it for the first time in the Algerian West coast.