Occurrence of glaucus atlanticus and glaucus marginata (blue ocean slug) from Nagapattinam coastal waters, southeast coast of India

Glaucidae is a taxonomic family of colorful sea slugs (blue ocean slugs). This is the first report presenting the occurrence of G. atlanticus and G. marginata in Nagapattinam coastal area, Bay of Bengal coastal shore (South East coast of India). All these animals float on the surface of the ocean being carried by the currents and the winds. Both species of G. atlanticus and G. matginata are closely associated with other open ocean invertebrates such as the Portuguese-man-of-war (Physalia physalis), the wind-sailor (Velella velella) and Porpita porpita. The nematocysts of Physalia pass unharmed through the digestive system and are used as defense system in the papillae. Male animals having its reproductive part (penis) with large looped and hook structure.