Xenacanthus


Xenacanthus

▪ fossil shark
      long-surviving but now extinct genus of freshwater sharks. Xenacanthus survived from the end of the Devonian Period, some 360 million years ago, to about the end of the Triassic Period, 208 million years ago. Xenacanthus had a slim, elongated body with a low dorsal fin that extended down most of it, almost merging with the triangular, pointed tail. From the back of the skull, a long, sharp, movable spine projected. This spine was made of bone. Though bone manufacture is not commonly associated with cartilaginous fishes, it is possible in certain tissues, such as the vertebrae, of certain shark species.

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Universalium. 2010.

Look at other dictionaries:

  • Xenacanthus — ? † Xenacanthus …   Википедия

  • Xenacanthus — Taxobox name = Xenacanthus fossil range = Devonian–Triassic regnum = Animalia phylum = Chordata classis = Chondrichthyes subclassis = Elasmobranchii ordo = Xenacanthida familia = Xenacanthidae genus = Xenacanthus synonyms = Pleuracanthus… …   Wikipedia

  • Xenacanthus —   Xenacanthus Rango temporal: Devónico Superior Triásico Superior …   Wikipedia Español

  • Xenacanthida — Taxobox name = Xenacanthida image width = 250px image caption = Orthacanthus senckenbergianus fossil range = Lower Carboniferous Middle Triassic regnum = Animalia phylum = Chordata classis = Chondrichthyes subclassis = Elasmobranchii superordo =… …   Wikipedia

  • Dimetrodon — Temporal range: Cisuralian Guadalupian …   Wikipedia

  • Xenacanthiformes —   Xenacanthiformes Rango temporal: Carbonífero Inferior Triásico Medio …   Wikipedia Español

  • Xenacanthida — ? † Xenacanthida …   Википедия

  • Xenacanthiformes — Expleuracanthus gaudri, Lebendrekonstruktion Zeitraum Unterdevon bis Obertrias 380 bis 220 Mio. Jahre Fundorte Europa …   Deutsch Wikipedia

  • fish — fishless, adj. /fish/, n., pl. (esp. collectively) fish, (esp. referring to two or more kinds or species) fishes, v. n. 1. any of various cold blooded, aquatic vertebrates, having gills, commonly fins, and typically an elongated body covered with …   Universalium

  • Fish — /fish/, n. Hamilton, 1808 93, U.S. statesman: secretary of state 1869 77. * * * I Any of more than 24,000 species of cold blooded vertebrates found worldwide in fresh and salt water. Living species range from the primitive lampreys and hagfishes… …   Universalium


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