Range
The ophiuroids diverged in the Early Ordovician, about 500 million years ago. Ophiuroids can be found today in all of the major marine provinces, from the poles to the tropics. In fact, crinoids, holothurians, and ophiuroids live at depths from 16–35 m, all over the world. Basket stars are usually confined to the deeper parts of this range. Ophiuroids are known even from abyssal (>6000 m) depths. However brittle stars are also common, if cryptic, members of reef communities, where they hide under rocks and even within other living organisms. A few ophiuroid species can even tolerate brackish water, an ability otherwise almost unknown among echinoderms. A brittle star's skeleton is made up of embedded ossicles.
Read more about this topic: Brittle Star
Famous quotes containing the word range:
“Culture is the suggestion, from certain best thoughts, that a man has a range of affinities through which he can modulate the violence of any master-tones that have a droning preponderance in his scale, and succor him against himself. Culture redresses this imbalance, puts him among equals and superiors, revives the delicious sense of sympathy, and warns him of the dangers of solitude and repulsion.”
—Ralph Waldo Emerson (1803–1882)
“[F]or as Socrates says that a wise man is a citizen of the world, so I thought that a wise woman was equally at liberty to range through every station or degree of men, to fix her choice wherever she pleased.”
—Sarah Fielding (1710–1768)
“but we wish the river had another shore,
some further range of delectable mountains,”
—Robert Lowell (1917–1977)