Agnatha

(redirected from Jawless fishes)
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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 ?
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.
Tiny scales of acanthodians often dominate fish microremains, particularly in drill core samples, and are much more common than macroremains of jawless fishes heterostracans (psammosteids) and/or placoderms.
Gareth Fraser, postdoctoral fellow at Georgia Tech's School of Biology, describes it as a common gene regulatory circuit that controls the development of all dentitions, from the first teeth in the throats of jawless fishes that lived half a billion years ago, to the incisors and molars of modern vertebrates.