Definition:
Salamanders represent one of the three orders of the Class: Amphibians.
Because of their tails, their gross features are like those of the Class:
Reptilia, which is even more specialized, but most scientists believe that
they represent primitive amphibians. Over 300 species are known. Newts
are a species of salamander that lives mainly in water.
Structure:
Because both the upper and lower
extremities of salamanders project at 90 degree angles from their torsos,
and they have a large tail, the skeletal
system of salamanders is developed for walking on soil. All young salamanders
have gills for respiration, but
they develop lungs during early adulthood.The gametes of male salamanders
are aggregated into a spermatophore which is collected in the cloaca
of the female, which then harbors the developing larvae which are expelled
alive; this is internal reproduction,also
shared by caecilians.
Function:
The awkward positioning of the pectoral
and pelvic girdles limits salamanders
ability to leap, and their walking is quite slow and labored. Some are
adept at swimming. Salamanders retain their body shape throughout their
lives, in contrast to frogs and toads which
begin as tadpoles, with tails, and emerge into adults by the process of
metamorphosis. Also, frogs and toads reproduce
by external methods.
