Crinoid shrimps come in an enormous variety of colours and patterns which always match the feather stars which they live on. It seems that the shrimp are able to adjust its colours over time to suit its host
About 2,400 meters (a mile and a half) below the surface of Monterey Bay, this “sea lily” clings to the wall of Monterey Canyon. Marine biologists call this animal a “stalked crinoid.” Crinoids are relatives of sea stars and sea urchins that live by capturing tiny food particles that drift by on ocean currents. The stalk on this crinoid keeps it up above the muddy seafloor, where the currents are slightly stronger. Like many sea stars, this stalked crinoid has five-fold symmetry, and a mouth located at the center of its feathery arms.
A stunning sea lily in the deep waters of Indonesia filters the current for food. Sea lilies are filter-feeding invertebrates (echinoderms). They catch particles from the water with tube feet located on arms that branch outward from the center stalk. Rarely seen, these creatures are much less common than they once were in ancient seas…
shallow marine ecosystem during the early Carboniferous Period (359-318 million years ago)
“… Crinoids include the camerates Dizygocrinus (under attack, bottom center, left) and the spiny Dorycrinus (bottom center, right), and the cladids Decadocrinus (bottom left) and Abrotocrinus (bottom right). Fishes include the cochliodont Deltoptychius (bottom center), the petalodont Janassa (left of center, ventral view), the chondrenchelyiform Chondrenchelys (far left), and the actinopterygian Amphicentrum (upper right).”
Fossil Crinoids (Uintacrinus socialis), Smithsonian National Museum of Natural History, Washington, D.C.
Because many crinoids resemble flowers, with their cluster of waving arms atop a long stem, they are sometimes called sea lilies. But crinoids are not plants. Like their relatives—starfishes, sea urchins, sea cucumbers, and brittle stars—crinoids are echinoderms, animals with rough, spiny surfaces and a special kind of radial symmetry based on five or multiples of five.
Crinoids have lived in the world’s oceans since at least the beginning of the Ordovician Period, roughly 490 million years ago. They may be even older. Some paleontologists think that a fossil called Echmatocrinus, from the famous Burgess Shale fossil site in British Columbia, may be the earliest crinoid. The Burgess Shale fossils date to the Middle Cambrian, well over 500 million years ago. Either way, crinoids have had a long and successful history on earth…
…rather than try and half-ass a post I thought it would be better to treat you to some incredible photos of feather stars aka crinoids. These are filter feeding echinoderms that use their long arms to pick food out of the water.
Crinoids have been around for a long while with fossils dating back to the Paleozoic. You may recognize fossil crinoids by their long stalk, but most recent crinoids are unstalked and are basically a cup with a bunch of arms emerging from the top surface.
The Ocean Through Time: Mississippian Marine Habitat
(359 - 318 million years ago)
Crinoids (echinoderms related to sea stars and sea urchins) dominate the Paleozoic shallow water habitat in this illustration. They evolved a variety of stalk heights, which enabled them to capture food at different levels above the sea floor. The base of their stalks was modified to anchor the animal securely in the soft sediment.
Crinoids were relative skyscrapers in the community, sometimes towering up to two meters (6.5 feet). Lacy bryozoans occupied a lower level. Below them, huge numbers of brachiopods monopolized the muddy bottom. Sharks cruised above these crinoid forests, while smaller bony fishes weaved among the crinoid stalks.
Crinoids feed by filtering small particles of food from the sea water with their feather like arms. The tube feet are covered with a sticky mucus that traps any food that floats past. Once they have caught a particle of food, the tube feet can flick it into the ambulacral groove, where the cilia are able to propel the stream of mucus towards the mouth
End-Permian Extinction, “Great Dying” Lasted < 200,000 Years
by Brian Handwerk
Long before the dinosaurs, a bleak environment of widespread fires and oxygen-poor coastal seawater killed off some 90 percent of all Earth’s living species. The whole process took less than 200,000 years, according to a new study of the planet’s most catastrophic mass-extinction event.
The end-Permian extinction probably isn’t as well known as the Cretaceous extinction that wiped out the dinosaurs some 65 million years ago. But the end-Permian collapse nearly spelled the end of life on Earth. Now scientists have painted a picture of just how fast the “Great Dying” unfolded 252 million years ago.
While the causes of the Permian extinction remain a mystery, from here on out, any theory must be compatible with a 200,000-year time frame centered around 252.28 million years ago, the authors assert. This time span is span indicated by analysis of fossils and chemical evidence of changes in Earth’s carbon cycle in rocks from southern China to Tibet...
The winners of mass extinction: With predators gone, prey thrives
In modern ecology, the removal or addition of a predator to an ecosystem can produce dramatic changes in the population of prey species. For the first time, scientists have observed the same dynamics in the fossil record, thanks to a mass extinction that decimated ocean life 360 million years ago.
What was bad for fish was good for the fish’s food, according to a paper published today in Proceedings of the National Academy of Sciences. Researchers from the University of Chicago, West Virginia University, and The Ohio StateUniversity find that the mass extinction known as the Hangenberg event produced a “natural experiment” in the fossil record with results that mirror modern observations about predator-prey relationships…
The marine invertebrates called crinoids filled the seas during the Carboniferous period and even earlier. Their fossils are frequently found in limestone from the period, giving the Carboniferous the nickname the “Age of the Crinoids.”