Unlike sea stars, brittle stars have long, thin arms without suckers on the ends of their tube feet.
With spines and test alone
Live in shallow sandy or muddy bottom regions Eat by positioning themselves into current and eat copepods or other zooplankton coming toward them. Once caught in tube feet the plankton are directed to the sand dollar’s mouth http://ronda.la/sandbucks/sand-dollar-faqs.htm
Tentacles around mouth help take in mud, sand Special protection-can expel organs in a tangled, sticky, toxic mass to scare away predators. Also, can just curl up and roll away.
Wave sticky arms in current to suspension feed. Usually stay stuck to one spot (hold onto coral or rocks) and just feed from there instead of travelling to find food. Mouth and anus on top (unlike other echinoderms)
Phylum echinodermata 2012 2013
Phylum EchinodermataKingdom Animalia
Name and Body Symmetry• echino = “bumpy” or“spiny”• derm = “skin”• Echinoderms are radiallysymmetrical=equal unitsarranged in a circle arounda central disk• Many have five equal unitsso we can specify that theyhave pentamerous radialsymmetry as adults
Distribution & Habitat, Reproduction-Found worldwide-Epibenthic, Epifauna-External fertilization-External development-Planktonic larvae(unlike adult they arebilaterally symmetrical)