Proterospongia

Proterospongia is a genus of single-celled aquatic organisms which form colonies. It belongs to the choanoflagellate class. As a colony-forming choanoflagellate, Proterospongia is of interest to scientists studying the mechanisms of intercellular signaling and adhesion present before animals appeared.

==Physical characteristics== Members of Proterospongia have the typical choanoflagellate cell structure characterized by a cell body 5-10μm in diameter with a 20-30μm apical flagellum surrounded by a collar of 15-25 actin-filled microvilli. The flagellum propels swimming cells through the water column and creates water currents through the microvilli, which trap foodstuff such as bacteria and detritus. The arrangement of organelles in Proterospongia appears consistent with other choanoflagellates and is characterized by an anterior dictyosome under the flagellar base, a central nucleus, peripheral mitochondria and a posterior food vacuole.