Page 182 - Ultimate Visual Dictionary (DK)

ANIMALS

Bony fish HOW FISH BREATHE
Fish “breathe” by extracting oxygen from water
through their gills. Water is sucked in through the
mouth; simultaneously, the opercula close to prevent
BONY FISH, SUCH AS CARP, TROUT, SALMON, perch, and the water from escaping. The mouth is then closed,
cod, are by far the best known and largest group of fish, and muscles in the walls of the mouth, pharynx, and
opercular cavity contract to pump the water inside
with more than 20,000 species (over 95 percent of all
over the gills and out through the opercula. Some fish
known fish). As their name suggests, bony fish have rely on swimming with their mouths open to keep
skeletons made of bone, in contrast to the cartilaginous water flowing over the gills.
skeletons of sharks, jawless fish, and their relatives (see Pharynx
pp. 178-179). Other typical features of bony fish include
a swim bladder, which functions as a variable-buoyancy
organ, enabling a fish to remain effortlessly at whatever Gill raker
depth it is swimming; relatively thin, bonelike scales; Water
a flap (called an operculum) covering the gills; and out
paired pelvic and pectoral fins. Scientifically, bony
Gill slit
fish belong to the class Osteichthyes, which is a
division of the superclass Gnathostomata Mouth
(meaning “jawed mouths”).
Water in
Operculum
Gill filament
EXAMPLES OF BONY FISH
Vertebra
Neural spine

MANDARINFISH
(Synchiropus splendidus)

OCEANIC SEAHORSE
(Hippocampus kuda)

ANGLERFISH
(Caulophryne jordani)

Hypural

Hemal spine
Caudal fin ray Radial
cartilage
Anal fin ray
LIONFISH
(Pterois volitans)

STURGEON SNOWFLAKE MORAY EEL
(Acipenser sturio) (Echidna nebulosa)
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