Taxonomic studies of marine dinoflagellates and distribution in the coastal waters of Kakinada, Andhra Pradesh, India Author Bhowal, A Zoological Survey of India, Protozoology Section, M Block, New Alipore, Kolkata, West Bengal - 700 053, India & Department of Zoology, University of Calcutta, Kolkata, West Bengal - 700 019, India * [E-mail: jasbose @ gmail. com] Author Purushothaman, J Zoological Survey of India, Protozoology Section, M Block, New Alipore, Kolkata, West Bengal - 700 053, India jasbose@gmail.com Author Siddique, A Zoological Survey of India, Protozoology Section, M Block, New Alipore, Kolkata, West Bengal - 700 053, India & Department of Zoology, University of Calcutta, Kolkata, West Bengal - 700 019, India * [E-mail: jasbose @ gmail. com] text Indian Journal of Geo Marine Sciences 2023 2023-08-31 52 8 390 401 journal article 299611 10.56042/ijms.v52i08.11023 007f04a1-b276-4297-b014-76644398954f 2582-6727 11622455 8. Ornithocercus magnificus Stein 1883 Diagnostic characters: Thecate dinoflagellate with slightly asymmetrical, round cell body. Scattered pores present on the body surface. Presence of left sulcal list. Presence of 5 main posteriorly positioned ribs, of which 3 ribs situated antapically. These main ribs form anastomoses between them ( Fig. 2i ). Distribution: Cosmopolitan in warm temperate to tropical waters. Tamil Nadu coast, India 10 , Bay of Bengal 12 - 13 , Great Nicobar Island, Andaman Sea 21 , Kochi coast, India 40 and Karnataka coast, India 41 , Maldives 39 , Indian Ocean 11 , ROPME Sea Area, Iranian coastal waters 25 , Mediterranean waters 26 , Gulf of Mexico 42 , Caribbean Sea 32 , Mexican waters, Pacific Ocean 33 , Brazil waters 29 , Vitória-Trindade Seamount Chain, South Atlantic Ocean 35 , Eastern Pacific Ocean 38 , Australian waters 31 . This species was recorded from the stations APK2 and APK3 (subsurface depths) for the first time in Kakinada waters, and in the state of Andhra Pradesh .