We have sea sponges living in our oceans today. Sea Sponges are some of the simplest multicellular organisms alive. They do not have brains, digestive, circulatory or nervous systems and, once rooted, do not move.
Sponge species are numerous and diverse. There are 8,550 living sponge species in the phylum Porifera, which is comprised of four distinct classes.
Demospongiae is the most diverse, containing 76.2% of all living sponges. Desmospongiae form complex bodies with monoaxon or tetraxon spicules. They can live in both marine and freshwater.
Hexactinellida, the rare glass sponges; Calcarea which contains all the calcareous sponges; and, Homoscleromorpha, the rarest and simplest class with 117 species. Homoscleromorpha has only recently been recognized so perhaps we will find more examples as we explore the world's oceans.
They are very skilled at filtering water and can pass more than 20,000 times their volume through their systems in a single day. They greatly aid in the water quality of coral reef ecosystems, filtering bacteria along with the water they process. They also aid with carbon, nitrogen and phosphorus as they filter it through their bodies and put it back into the ecosystem via their excrement.
Pirania is named after Mount St. Piran, near the Bow River Valley, Banff National Park, Alberta, Canada. It was first described by Charles Doolittle Walcott in 1920 from 128 fossil specimens found within the Greater Phyllopod bed, the most famous fossil-bearing member of the 508 million-year-old Burgess Shale Fossil Lagerstätte in the Canadian Rockies of British Columbia. The type locality has exceptional preservation of soft-bodied animals from the Middle Cambrian.
