16 CLASS CHONDRICHTHYES and CLASS OSTEICHTHYES Flashcards
970 living species; mostly marine with only 28
freshwater species
* Cartilaginous skeleton: Bone is entirely
absent, but phosphatized mineral tissues are
retained in teeth, scales, and spines
* Sharks, skates, rays, chimaeras, and ratfish;
Includes one of the largest living vertebrate
species
Class CHONDRICHTHYES
(chondros = “_______” + ichthys = “_____”)
cartilage, fish
upper tail fin that is part of the vertebral column; it provides thrust and some lift as it sweeps back and forth
Heterocercal tail / Upper Caudal Tail
lower tail fin that is not part of the vertebral column; it is smaller than the
heterocercal tail
Lower Caudal Tail
are those that are homologous to limbs of 4-legged chordates:
Major/Appendicular Fins
lateral fins; supported by appendicular skeletons and homologous to
forelimbs (arms)
Pectoral fins (paired)
fins located on the ventral surface; supported by appendicular skeleton and
homologous to hindlimbs (legs)
Pelvic fins (paired)
extensions of the pelvic fins that is used for copulation
Claspers (males only)
are more for support and balance in swimming:
Minor Fins
usually triangular fin/s on top (dorsal) central line of body
Median Dorsal Fin (one or 2)
located at the underside behind the anus
Median Anal Fin (unpaired)
for sense of smell (the fact that they are large means they
have excellent sense of smell)
2 large olfactory lobes
for sight (excellent vision in water)
2 large optic lobes
(hindbrain)
Medulla oblongata
located laterally on dorsal side of the head. They are
lidless (there is no need for eyelids to maintain eye moisture when they are already surrounded by water)
eyes
electroreceptors located on the ventral side of the head. It is used to hunt prey by detecting their bioelectrical fields in the water.
Ampullae of Lorenzini
a horizontal line that runs across the sides of its body (often very visible); it is
composed of special receptors that is used to detect prey from very long distances by sensing their
vibrations in water.
lateral line system
Endoskeleton entirely made of
cartilage
persists until adulthood, but reduced
notochcord
Scales of sharks are called
placoid scales
shark (teeth are
continually replaced throughout life)
polyphyodont
a common chamber and outlet which the intestinal, urinary, and genital tracts open.
cloaca
Respiration by means of 5-7 pairs of gills
the gills are exposed
If oviparous, eggs are horny capsules called
mermaid’s purse
The 2 dorsal fins look different (the anterior is_____ the posterior is ____ .
spiny, soft
(a calcium carbonate structure that is similar to the cochlea in the inner ear of mammals)
otolith
unique to bony fishes, it is a large, thin- walled sac lying in the dorsal part of the body cavity.
swim-bladder
This is a paired appendicular fin in fishes that is homologous to forelimbs.
pectoral fins
This structure allows true fishes to maintain afloat
swim bladder
This is a system of sensory cells along the sides of a fish’s body and is used to detect vibrations in the
water.
Lateral-line
These are sensory receptors on the head of a shark that detects bioelectrical currents from their prey
Ampullae of Lorenzini
This refers to the continuous replacement of teeth throughout the life of a shark.
Polyphyodont
