What is a Pentadactyl Limb?
It
is a limb that has 5 limbs on the hand and foot.
All
the bones are symmetrical to the other limbs; such as both hands, both feet as
other Pentadactyl animals.
Examples
of Pentadactyl animals are; Whales,
Bats, Pre-evolved Horses and most mammals.
A Brief History
Extinct species; that existed 380-360
million years ago (the first known Tetrapods) developed 8 digits when evolving
into land mammals.
Over time, the number of digits reduced
to an average of 5 digits.
However, in some cases, some animals are
born with extra or missing digits. This is due to a mutation.
Which Animals Have Pentadactyl Limbs?
It is most common with humans and other
mammals, except whales and dolphins, as they have evolved, their back limbs
have reseeded back into their bodies, as they no longer need them. Also, with
no external hind legs, it allows them to move easily through the water.
Other mammals have extra digits, such as
Pandas, which have digits.
Mammals, such as Moles appear to have
extra digits, however, these are only out-growth bones on their wrist.
Pentadactyl limbs are most common with
Tetrapods; 4 limbed creatures.
Other Animals With Pentadactyl Limbs
These are Birds, Dinosaurs, Reptiles and
Amphibians. For example, Amphibians such as frogs have 4 digits, and Birds only
have 3.
Extinct Tetrapods, Dinosaurs, had 3 toes,
and Marine mammals have 5 digits.
Another example is the bat. Their fingers
have adapted; elongating to help form the bats wings, while the thumb is used
to grip onto trees.
Examples
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