Sea urchin - Wikipedia Two species of sea urchins, the Echinometra viridis (bottom left) and Tripneustes ventricosus (top right) Sea urchins or urchins ( ˈɜːrtʃɪnz ) are echinoderms in the class Echinoidea About 950 species live on the seabed, inhabiting all oceans and depth zones from the intertidal zone to deep seas of 5,000 m (16,000 ft) [1]
Echinoidea - Digital Atlas of Ancient Life Echinoidea comes from the Greek word ‘echinos’ meaning “spiny” and includes the sea urchins, sand dollars, and heart urchins Echinoids are the sister taxa to holothuroidians within the Echinozoa clade
Echinoidea | INFORMATION | Animal Diversity Web - ADW There are approximately 940 species of echinoids distributed worldwide in marine habitats from the intertidal to 5000 meters deep Their fossil record is extensive due to their test (an internal skeleton), and dates back to the middle Ordovician period
Sea urchin | Description, Anatomy, Facts | Britannica Sea urchin, any of about 950 living species of spiny marine invertebrate animals (class Echinoidea, phylum Echinodermata) with a globular body and a radial arrangement of organs, shown by five bands of pores running from mouth to anus over the test (internal skeleton)
World Echinoidea Database - World Register of Marine Species Echinoids, or sea urchins (oursins [French], Seeigel [German], erizos de mar [Spanish]) constitute a group of exclusively marine invertebrates inhabiting the intertidal down to the deep-sea trenches They are characterized by a globose or flattened skeleton known as a test
Echinoidea - an overview | ScienceDirect Topics Echinoidea is defined as a class within the phylum Echinodermata that includes marine animals such as sea urchins and sand dollars, characterized by their distinctive pentaradial symmetry and an endoskeleton made of calcium carbonate