Aggregata andresi n. sp. (Apicomplexa: Aggregatidae) from the ommastrephid squid Martialia hyadesi in the SW Atlantic Ocean and some general remarks on Aggregata spp. in cephalopod hosts.

A new species of coccidian, Aggregata andresi, is described from the digestive tract of the flying squid Martialia hyadesi, an ommastrephid squid that lives in cold subantarctic waters in the Southwest Atlantic. Gamogonic and sporogonic stages were observed in the digestive tract of 96.5% studied hosts. Oocysts were ovoid to subspheroid in shape, 170-590 microm in length and 200-530 microm in width. Each oocyst contained approximately 45,000 sporocysts. Sporocysts measured 9.5-10 microm in length and 8-8.5 microm in width. The surface of the sporocyst wall was smooth and the cyst wall thick. Each sporocyst contained three sporozoites measuring 16-20 microm in length and 2-2.5 microm width. A. andresi is the second species of Aggregata to be reported from a nerito-oceanic cephalopod host.