Latin Name: Tuscaridium cygneum
Geographic Location: Worldwide
Size: 1 millimetre

Radiolarians are part of the marine plankton and occur in all oceans, but are most abundant in the upper few hundred meters of the open oceans. Radiolarians have existed for 600 million years resulting in extremely diverse and intricate shapes. They take their name from the radial symmetry, often marked by radial skeletal spines. They have a central capsule which is enclosed in a membrane which contains the nucleus, respiratory and secretory cell organs, and food reserves. It is surrounded by ectoplasm which can extend into a complex network of temporary locomotive protrusions (pseudopodia). These pseudopods can actively capture prey, dispose of wastes, and react to stimuli. Individual radiolarians are normally less than a millimetre, but some can grow large enough to be seen with the naked eye. Some species can amass into colonies, which may reach centimetre or even metre scales and when disturbed create a bioluminescent glow.