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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 .
The Cambrian chordates are an extinct group of animals belonging to the phylum Chordata that lived during the Cambrian, between 538 and 485 million years ago.The first Cambrian chordate known is Pikaia gracilens, a lancelet-like animal from the Burgess Shale in British Columbia, Canada.
This article contains a list of all of the classes and orders that are located in the Phylum Chordata. 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.
Pikaia gracilens is an extinct, primitive chordate marine animal known from the Middle Cambrian Burgess Shale of British Columbia.Described in 1911 by Charles Doolittle Walcott as an annelid, and in 1979 by Harry B. Whittington and Simon Conway Morris as a chordate, it became "the most famous early chordate fossil", [1] or "famously known as the earliest described Cambrian chordate". [2]
The dorsal nerve cord serves as a hollow-like backbone where signals are sent throughout the body due to nervous tissue being located in this region. [2] The notochord is also toward the tail of the chordate but closer toward the middle of the body than the dorsal nerve cord and is a water-filled structure that allows the chordate to move in ...
The lancelets (/ ˈ l æ n s l ɪ t s, ˈ l ɑː n-/ LA(H)N-slits), also known as amphioxi (sg.: amphioxus / ˌ æ m f i ˈ ɒ k s ə s / AM-fee-OK-səs), consist of 32 described species of "fish-like" benthic filter feeding chordates [9] in the subphylum Cephalochordata, class Leptocardii, and family Branchiostomatidae.
Agnatha (/ ˈ æ ɡ n ə θ ə, æ ɡ ˈ n eɪ θ ə /; [3] from Ancient Greek ἀ-(a-) 'without' and γνάθος (gnáthos) 'jaws') is a paraphyletic infraphylum [4] of non-gnathostome vertebrates, or jawless fish, in the phylum Chordata, subphylum Vertebrata, consisting of both living (cyclostomes) and extinct (conodonts, anaspids, and ostracoderms, among others).
Vertebrates have a segmented vertebral column.. Segmentation in biology is the division of some animal and plant body plans into a linear series of repetitive segments that may or may not be interconnected to each other.