Diversity of fish (Wiki)
" Jawless fish are the most primitive fish. ... Extant jawless fish are either lamprey or hagfish."
" Cartilaginous fish have a cartilaginous skeleton. ...There are over 980 species of cartilaginous fish. They include sharks, rays and chimaera."
The lobe finned fish is the class of fleshy finned fishes, consisting of lungfish, and coelacanths. They are bony fish with fleshy, lobed paired fins, which are joined to the body by a single bone. These fins evolved into the legs of the first tetrapod land vertebrates, amphibians."
"Ray finned fishes are so-called because they possess lepidotrichia or "fin rays", their fins being webs of skin supported by bony or horny spines ("rays").
There are three types of ray finned fishes: the chondrosteans, holosteans, and teleosts."
"Teleosts are the most advanced or "modern" fishes. They are overwhelmingly the dominant class of fishes (or for that matter, vertebrates) with nearly 30,000 species, covering about 96 percent of all extant fish species."
"Fish adopt a variety of strategies for nurturing their brood. Sharks, for example, variously follow three protocols with their brood. Most sharks, including lamniformes are ovoviviparous, bearing their young after they nourish themselves after hatching and before birth, by consuming the remnants of the yolk and other available nutrients. Some such as hammerheads are viviparous, bearing their young after nourishing hatchlings internally, analgously to mammalian gestation. Finally catsharks and others are, oviparous, laying their eggs to hatch in the water.
Some animals, predominantly fish such as cardinalfish practice mouthbrooding, caring for their offspring by holding them in the mouth of a parent for extended periods of time. Mouthbrooding has evolved independently in several different families of fish.
The Mauthner cell and other identified neurons of the brainstem escape network of fish.
Evidence for a widespread brain stem escape network in larval zebrafish. - Free full text -
Neural control and modulation of swimming speed in the larval zebrafish.
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Only one mention of GABA, and it was phasic rather than tonic.
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