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Hemiasteridae
Hemiasteridae is a family of echinoderms belonging to the order Spatangoida The heart urchins or Spatangoida are an order of sea urchins. Their body is a somewhat elongated oval in form, and is distinguished by the mouth being placed towards one end of the animal, and the anus towards the other. As a result, heart urc .... Genera Genera: * '' Bolbaster'' Pomel, 1869 * '' Cheopsia'' Fourtau, 1909 * '' Hemiaster'' Agassiz, 1847 References Spatangoida Echinoderm families {{echinoderm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spatangoida
The heart urchins or Spatangoida are an order of sea urchins. Their body is a somewhat elongated oval in form, and is distinguished by the mouth being placed towards one end of the animal, and the anus towards the other. As a result, heart urchins, unlike most other sea urchins, are bilaterally symmetrical, and have a distinct anterior surface. The presence and position of the mouth and anus typically give members of this group the distinct "heart" shape from which they get their name. Heart urchins have no feeding lantern, and often have petaloids sunk into grooves. They are a relatively diverse order, with a number of varying species. Taxonomy According to World Register of Marine Species : * suborder Brissidina Stockley, Smith, Littlewood, Lessios & MacKenzie-Dodds, 2005 ** family Asterostomatidae Pictet, 1857 ** family Brissidae Gray, 1855 ** family Palaeotropidae Lambert, 1896 ** super-family Spatangidea Fischer, 1966 *** family Eupatagidae Lambert, 1905 *** family ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinoderms
An echinoderm () is any member of the phylum Echinodermata (). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies". Adult echinoderms are found on the sea bed at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7,000 living species, making it the second-largest grouping of deuterostomes, after the chordates. Echinoderms are the largest entirely marine phylum. The first definitive echinoderms appeared near the start of the Cambrian. The echinoderms are important both ecologically and geologically. Ecologically, there are few other groupings so abundant in the biotic desert of the deep sea, as well as shallower oceans. Most echinoderms are able to reproduce asexually and regenerate tissue, organs, and limbs; in some cases, they can undergo complete regeneration from a single limb. Geolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
