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Vertebrates belong to the chordates, a phylum characterised by five synapomorphies (unique characteristics), namely a notochord, a hollow nerve cord along the back, an endostyle (often as a thyroid gland), and pharyngeal gills arranged in pairs. Vertebrates share these characteristics with other chordates.
A craniate is a member of the Craniata (sometimes called the Craniota), a proposed clade of chordate animals with a skull of hard bone or cartilage.Living representatives are the Myxini (hagfishes), Hyperoartia (including lampreys), and the much more numerous Gnathostomata (jawed vertebrates).
It is the largest class of vertebrates in existence today. Osteichthyes is divided into the ray-finned fish ( Actinopterygii ) and lobe-finned fish ( Sarcopterygii ). The oldest known fossils of bony fish are about 420 million years ago, which are also transitional fossils , showing a tooth pattern that is in between the tooth rows of sharks ...
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.
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).
Marine vertebrates are ... Pteraspidomorphi is an extinct class of early jawless fish ancestral to jawed vertebrates. The few characteristics they share with ...
A majority of paleontologists use the term "tetrapod" to refer to all vertebrates with four limbs and distinct digits (fingers and toes), as well as legless vertebrates with limbed ancestors. [ 15 ] [ 16 ] Limbs and digits are major apomorphies (newly evolved traits) which define tetrapods, though they are far from the only skeletal or ...
It is the largest class of vertebrates in existence today, encompassing most aquatic vertebrates, as well as all semi-aquatic and terrestrial vertebrates. The group is divided into two main clades , the ray-finned fish ( Actinopterygii , which makes up the vast majority of extant fish) and the lobe-finned fish ( Sarcopterygii , which gave rise ...