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The Paleozoic echinoderms were globular, attached to the substrate and were orientated with their oral surfaces facing upwards. These early echinoderms had ambulacral grooves extending down the side of the body, fringed on either side by brachioles, like the pinnules of a modern crinoid. Eventually, except for the crinoids, all the classes of ...
Ctenocystoidea is an extinct clade of echinoderms, which lived during the Cambrian and Ordovician periods. Unlike other echinoderms, ctenocystoids had bilateral symmetry, or were only very slightly asymmetrical. They are believed to be one of the earliest-diverging branches of echinoderms, with their bilateral symmetry a trait shared with other ...
The name urchin is an old word for hedgehog, which sea urchins resemble; they have archaically been called sea hedgehogs. [6] [7] The name is derived from the Old French herichun, from Latin ericius ('hedgehog'). [8] Like other echinoderms, sea urchin early larvae have bilateral symmetry, [9] but they develop five-fold symmetry as they mature ...
Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (/ ˌæstəˈrɔɪdiə /). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish are also known as asteroids due to being in the class Asteroidea.
A brittle star, Ophionereis reticulata A sea cucumber from Malaysia Starfish exhibit a wide range of colours. This List of echinoderm orders concerns the various classes and orders into which taxonomists categorize the roughly 7000 extant species [1] as well as the extinct species of the exclusively marine phylum Echinodermata.
Category. : Echinoderms. Wikimedia Commons has media related to Echinodermata. Echinoderms (sea urchins, sea lilies, sea stars, crinoids, ...) are animals in the phylum Echinodermata. There are 5 subphyla, some of them being extinct: †Homalozoa, Crinozoa, Asterozoa, Echinozoa and †Blastozoa.
Ophiomusa. Ophiomusa is a genus of echinoderms belonging to the family Ophiolepididae [1] that includes: sea urchins, sand dollars and sea cucumbers. Ophiurida are similar to starfish; they both have a central disc and five arms sprouting from the disc. One of the main distinguishing factors of an Ophiuroid is its arms; the arms of an Ophiurida ...
This list of prehistoric echinoderms is an attempt to create a comprehensive listing of all genera that have ever been included in the Echinoderms that have been preserved as fossils. This list excludes purely vernacular terms. It includes all commonly accepted genera, but also genera that are now considered invalid, doubtful ( nomina dubia ...