fishes

agnathoa
a superclass of jawless fish in the phylum Chordata, subphylum Vertebrata.
gnathostome
any vertebrate of the superclass Gnathostomata , having a mouth with jaws, including all vertebrates except the agnathans
elasmobranchii
a subclass of Chondrichthyes or cartilaginous fish, that includes the sharks (Selachii) and the rays and skates (Batoidea).
heterocercal
Ichthyol of or possessing a tail in which the vertebral column turns upwards and extends into the upper, usually larger, lobe, as in sharks Compare homocercal
claspers
a male anatomical structure found some groups of animals, used in mating
placoid scales
are tough scales that cover the skin of elasmobranchs (sharks and rays).
spiral valve
the lower portion of the intestine of some sharks, rays, skates and bichirs.
caudal
2. situated more toward the cauda, or tail, than some specified reference point; toward the inferior (in humans) or posterior (in animals) end of the body.
lateral-line system
allows the detection of movement and vibrations in the water surrounding an animal,
ampullae of Lorenzini
are special sensing organs called electroreceptors, forming a network of jelly-filled pores.
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”),
lobe-finned
fishes are chordates of class Sarcopterygii.
teleost
have a movable maxilla and premaxilla and corresponding modifications in the jaw musculature.
neopterygian
Neopterygii is a group of Actinopteri animals. Neopterygii means “new fins”. There are only few changes during their evolution from the earlier actinopterygians
chondrostean
Chondrostei any member of a group of primitive ray-finned bony fishes that make up one of the three major subdivisions of the superclass Actinopterygii,
osteichthyes
are a taxonomic group of fish that have bone, as opposed to cartilaginous, skeletons
operculum
a small covering or lid, and is widely used in descriptions of the animal and plant world.
placenta
A membranous vascular organ that develops in female mammals during pregnancy,
oviparous
animals are animals that lay eggs, with little or no other embryonic development within the mother.
ovoviviparous
ovovivipary, or ovivipary, is a mode of reproduction in animals in which embryos develop inside eggs that are retained within the mother’s body
viviparous
Giving birth to living offspring that develop within the mother’s body
swim bladder
gas bladder, fish maw or air bladder is an internal gas-filled organ that contributes to the ability of a fish to control its buoyancy,
ganoid scales
can be found on gars (family Lepisosteidae) and bichirs and reedfishes
ctenoid scales
shows the outer surface of four of the scales,