Agnatha

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Related to jawless fish: coelacanth, cartilaginous 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.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
References in periodicals archive ?
Bringing that environmental context together with what was already known about the family tree relationships of vertebrates from the middle Paleozoic, 480 to 360 million years ago, the researchers created a database that involved 2,728 early records for jawed and jawless fishes.
Like many scale-bearing sharks and bony fishes, most extinct, jawless fishes possessed articulating dermal bones that were suggested to be adaptations against predators (Carroll, 1988).
Over 460 million years ago the first jawless fish swam in shallow seas of what was to become the Appalachian basin of North America.
ROSEBURG - A dam on the North Umpqua River has been modified to make the spawning migration easier for lamprey - a jawless fish that is often mistaken for an eel.
For their experiments, Lau and Morgan used as a model organism the sea lamprey, which is a jawless fish. Unlike most other vertebrates, including humans, lampreys spontaneously recover to an extraordinary degree after SCI.
The sea lamprey, river lamprey and brook lamprey ( all kinds of jawless fish ( also find the weir impossible to negotiate as they migrate up stream to spawn.
Scottish Natural Heritage sent two geologists to Germany to reclaim the unique fossils of jawless fish and an arthopod, a triangular-shaped creature.
The biological systems they selected - the nervous systems of a leech and a lamprey, an eel-like jawless fish - are particularly suited to VLSI-circuit modeling.