First record of Adipicola Leticiae (Bivalvia: Mytilidae, Bathymodiolinae) in the Southeastern Pacific

JAVIER H. SIGNORELLI; SELLANES, JAVIER; ASOREY, CYNTHIA M.

Congreso; XI CLAMA. Congreso Latinoamericano de Malacología; 2020

Adipicola leticiae Signorelli & Crespo, 2017, was described for the Argentine Sea. New samples from a methane seep site off central Chile (36°21.997´S, 73°42.785´W) revealed the presence of this species in the SE Pacific. The individuals were collected at 775 m depth by the ROV Kiel 6000, using scoop nets. Single or articulated valves were exclusively sampled, thus, no anatomical features have been examined. Shell characters such as equivalve, antero-posteriorly elongate shell, length up to 15.9 mm, external surface smooth without periostracal hair, not gaped and hinge plate without teeth or crenulations below umbo or behind ligament in adults were observed and compared with the type material. Additional morphological characters include the presence of rounded ends, dorso-anterior margin anteriorly inclined but dorso-posterior portion straight, lunule not defined and ventral margin straight. Also the size of prodisoconch 1 and 2 of sampled specimens coincides with the observed in the type material. However, genetic and anatomical analysis, once fresh samples from Chile are available, should rule out potential crypticism. This new finding constitutes the first record of a recent Bathymodiolinae mussel and the fifth chemosymbiotic bivalve for the Southeastern Pacific Ocean. Other records of deep sea bivalves associated to seeps, vents or whale falls belong to Lucinidae (Lucinoma anemiophila Holmes, Oliver & Sellanes, 2005), Thyasiridae (Thyasira methanophyla Oliver & Sellanes 2005) and Vesicomyidae (Calyptogena australis, Stuardo & Valdovinos 1988, Calyptogena gallardoi Sellanes & Krylova, 2005). The present study updates and contributes to the knowledge of deep-water bivalve biodiversity in Chilean waters.