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  2. Chordate - Wikipedia

    en.wikipedia.org/wiki/Chordate

    A chordate (/ ˈ k ɔːr d eɪ t / KOR-dayt) is a deuterostomal bilaterian animal belonging to the phylum Chordata (/ k ɔːr ˈ d eɪ t ə / kor-DAY-tə).All chordates possess, at some point during their larval or adult stages, five distinctive physical characteristics (synapomorphies) that distinguish them from other taxa.

  3. Craniate - Wikipedia

    en.wikipedia.org/wiki/Craniate

    This, combined with an apparent lack of vertebral elements within the Myxini, suggested that the Myxini were descended from a more ancient lineage than the vertebrates, and that the skull developed before the vertebral column. The clade was thus composed of the Myxini and the vertebrates, and any extinct chordates with skulls.

  4. List of chordate orders - Wikipedia

    en.wikipedia.org/wiki/List_of_chordate_orders

    The subphyla Tunicata and Vertebrata are in the unranked Olfactores clade, while the subphylum Cephalochordata is not. Animals in Olfactores are characterized as having a more advanced olfactory system than animals not in it. The only extinct classes shown are Placodermi and Acanthodii. Note that there are many other extinct chordate groups ...

  5. Lancelet - Wikipedia

    en.wikipedia.org/wiki/Lancelet

    Also like vertebrates, the muscles are arranged in blocks called myomeres. [50] Unlike vertebrates, the dorsal nerve cord is not protected by bone but by a simpler notochord made up of a cylinder of cells that are closely packed in collagen fibers to form a toughened rod. The lancelet notochord, unlike the vertebrate spine, extends

  6. Deuterostome - Wikipedia

    en.wikipedia.org/wiki/Deuterostome

    On the other hand, fossils of early chordates are very rare, as non-vertebrate chordates have no bone tissue or teeth, and fossils of no Post-Cambrian non-vertebrate chordates are known aside from the Permian-aged Paleobranchiostoma, trace fossils of the Ordovician colonial tunicate Catellocaula, and various Jurassic-aged and Tertiary-aged ...

  7. Marine invertebrates - Wikipedia

    en.wikipedia.org/wiki/Marine_invertebrates

    Non-craniate chordates are close relatives of vertebrates The lancelet , a small translucent fish-like Cephalochordate , is the closest living invertebrate relative of the vertebrates. [ 73 ] [ 74 ]

  8. Olfactores - Wikipedia

    en.wikipedia.org/wiki/Olfactores

    Olfactores represent the overwhelming majority of the phylum Chordata, as the Cephalochordata are the only chordates not included in the clade. This clade is defined by a more advanced olfactory system which, in the immediate vertebrate generation, gave rise to nostrils.

  9. Notochord - Wikipedia

    en.wikipedia.org/wiki/Notochord

    In most vertebrates, the notochord develops into secondary structures. In other chordates, the notochord is retained as an essential anatomical structure. The evolution of the notochord within the phylum Chordata is considered in detail by Holland and Somorjai (2020). Vertebrates now have spines so they do not need a notochord. [26]