Helicoplacus is the genus name for two species of absolutely ancient Echinoderm. They are the earliest Echinoderm fossils that have ever been studied, and the specimens are pretty well preserved for being half a billion years old!
Helicoplacus species had skinny pine-cone shaped bodies that were vertically oriented and attached to the sea floor. They had very primitive respiratory systems, and there is dispute about where the mouth actually was. It is believed that the grooves that circled the bodies actually helped move food into a mouth, wherever it was placed.
Members of the genus lived for around 15 million years before going extinct.
Status : Extinct for over 500 million years
Location : Fossils found in North America
Size : Length up to 2.8in (7cm)
Classification : Phylum : Echinodermata -- Class : †Helicoplacoidea -- Genus : Helicoplacus