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Echinothuriidae is a family of sea urchins in the order Echinothurioida. Due to their soft skeletton most are called "leather urchins", but species in the genus ''Asthenosoma'' are also known as "fire urchins" due to their bright colors and painful venomous sting. == Description and characteristics == These sea urchins have a disc-like body, more or less bulging, structured by a flexible test, which is nearly unique among sea urchins. Most species can grow quite big and live in deep seas, though some genera contain shallow species (especially ''Asthenosoma''). The test is composed of thin and weakly calcified plates, not always continuous. The spines are attached to perforated and non-crenulated tubercles. Spines from the oral face are ending with a hyaline hoof, which allows walking on soft substrate. The jaw (Aristotle's lantern) has 5 aulodont teeth. This family seems to have appeared at the end of the Cretaceous.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Echinothuriidae」の詳細全文を読む スポンサード リンク
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