Fig. 1
From: Conserved expression of vertebrate microvillar gene homologs in choanocytes of freshwater sponges
Phylogenetic distribution of microvilli and microvilli-associated proteins. a Sponge choanocytes have an apical ring of actin-cored (red) microvilli that are connected by intermicrovillar links. This structure called a “collar” surrounds a microtubule-cored (blue) flagellum that functions to generate flow through the water-canal system. Microvilli are found in diverse animal cell types. Two of the best-studied examples include mechanosensory hair cells of the vertebrate inner ear, and enterocytes of the vertebrate intestinal epithelium. b Phylogenetic distribution of microvillar proteins that are conserved between sponges and vertebrates