First observation of radiolarian reproduction in the laboratory

This is the first observation of sexual reproduction of polycistine radiolaria in the laboratory. This species (Tholospira cervicornis Haeckel) was taken by plankton tow from the Tsugaru Strait, between Hokkaido and Honshu island, northern part of Japan. A lot of swarmers (gametes) were released from the host, and dispersed quickly. About 5 hours after from the start of gamete release, all gametes had been ejected, but some dark red colored pigments (symbiont or some kind of organelle?) were still inside of the host. Copyright: Dr. K. Kimoto, Japan Agency for Marine-Earth Science and Technology (JAMSTEC)