Ossurans planii
A benthic filter-feeding Ossuran living in the ocean around the Smirka Islands. O. planii utilizes extended intake siphons to take in water and organic matter. The organic matter is filtered out by an internal filtration organ that moves the food to the gut via cilia. The water passes over the gills to extract dissolved oxygen for respiration then is released through a single output siphon. The output siphon also acts as the anus and genital opening, releasing waste and gametes into the water. They reach an adult size of 6cm across with 1-2cm intake siphons.
O. planii are hermaphroditic and reproduce by broadcast spawning. They will release gametes during the arctic summer when primary production is the highest. Zygotes initially are planktonic, feeding on detritus in the water column. Once their siphons are developed they will direct their movement using the output siphon. Once they are around 3cm they will begin to build up a store of minerals from the water and swim towards the ocean floor. Once at the ocean floor they produce a calcareous shell with glands on the skin of the main body. The shell has five holes, four for intake siphons and one for the output siphon. The shell is 3cm larger than the organism to allow it to continue to grow inside the shell.
