Unfortunately, even though there are way, way more invertebrates, it can be incredibly difficult to find exact information about a single species. To be fair, some are quite prolific- like the American Lobster, Black Widow, and Common Octopus. But other times it is difficult to say much about an entire family, much less a specific genus or species.
Such is the case today with the Brittlestar. There are close to 2,000 species within the Ophiurida order, and they can be found in oceans worldwide. Not only is their geographic range huge, but they also live in many different ocean environments, from shallow coasts to deep sea floors!
Brittlestars are named for their starfish-like bodies and long, stringy arms that break away easily when they are under attack. Don't worry, the arms grow back! They are also very fast movers, and tend to come in camouflaging colors. These are excellent traits to have when you have literally dozens, if not hundreds of predators.
Brittlestars, and many other invertebrates, are so interesting because they are so very different anatomically from more familiar critters. They don't have brains! Their mouth and anus are the same exact orifice! They sense light and smells through their feet! Some of them are even bioluminescent! Most species feed on floating debris that they grab using their arms and transport to their central organs, but some also make use their tooth-ringed mouth/anuses to feed on small animals.
Location : Worldwide
Size : Typical body diameter around 1in (2.5cm)
Classification : Phylum : Echinodermata -- Class : Ophiuroidea -- Order : Ophiurida