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Agnatha (/ ˈ æ ɡ n ə θ ə, æ ɡ ˈ n eɪ θ ə /; from Ancient Greek ἀ-(a-) 'without', and γνάθος (gnáthos) 'jaws') is an infraphylum of jawless fish in the phylum Chordata, subphylum Vertebrata, consisting of both living (cyclostomes) and extinct (conodonts, anaspids, and ostracoderms) species.
Agnathan, (superclass Agnatha), any member of the group of primitive jawless fishes that includes the lampreys (order Petromyzoniformes), hagfishes (order Myxiniformes), and several extinct groups. Hagfishes are minor pests of commercial food fisheries of the North Atlantic, but lampreys, because.
Sep 2, 2019 · Agnatha are fish that have existed for over 470 million years. Although most agnatha are now extinct, some have found unique and interesting ways to survive. Agnatha or jawless fish can be found in waters all over the world, and they share few characteristics with other marine mammals.
The superclass Agnatha describes fish that lack jaws and includes the extant species of hagfish and lampreys.
Sep 23, 2023 · Lampreys belong to an ancient group of fish called Agnatha that evolved 450 million years ago, predating both dinosaurs and trees. Instead of a jaw, lampreys have a sucker mouth that they use to...
The Agnatha is a superclass of fish. It is paraphyletic. This means it is a convenient catch-all term, which does not follow the rules of cladistics. For example, most extinct agnathans belong to the stem group (ancestral group) of gnathostomes.
Agnathan - Evolution, Classification, Jawless: Superclass Agnatha have fossils dating from the Ordovician Period, and are distinguishable from the other craniates by their lack of jaws. Living orders are Petromyzontiformes (lampreys) and Myxiniformes (hagfishes).
