Agnatha

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Related to Jawless vertebrates: jawless fish

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 ?
By imaging the internal structure of the skull using high-energy X-rays at the European Synchrotron (ESRF) in Grenoble, France, the authors show that the skull housed a brain with a short front end, very similar to that of a jawless vertebrate.
Now, an international team of researchers, led by a faculty member from the University of Colorado, has noted that three genes in jawless vertebrates might have been key to the development of jaws in higher vertebrates.