Agnatha

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Related to Jawless fishes: superclass Agnatha, Cartilaginous fishes

Agnatha

aquatic, jawless, fish-like vertebrates characterized by fewer than two pairs of limbs (fins). The group is often given the status of a subphylum to separate it from other vertebrates with jaws which are included in the subphylum Gnathostomata. The Agnatha includes lampreys, hagfish, and the fossil OSTRACODERMI.
References in periodicals archive ?
Numerous jawless fishes characteristic of the Siberian Early Devonian, amphiaspidids, come mostly from the Siberian Platform, also from the adjacent Tajmyr Peninsula.
And just because the species is classified as agnaths, which means "jawless fishes," don't underestimate its bite.
Thornton proposes that the gene duplication that created the progesterone receptor took place before the jawless fishes branched off the rest of the vertebrate line.