One
obvious difference between Rhamphorhynchoids and
Pterodactyloids is the presence of a long tail in the
Rhamphorhynchoids. The tail includes up to 40 vertebrae and
was cross braced and stiffened by a system of longitudinal
tendons. The function of the tail remains unclear: it
certainly helped the animal steer once airborne but it may
have also helped in counterbalancing the weight of the skull
when the animal was on the ground.
As characterized by all pterosaurs, the wing
membrane is stretched by an elongated fourth finger. The
wrist bones are not fused and the phalanges are longer than
the metacarpals. In the shoulder, the clavicle was not fused
to the sacral vertebrae as in the larger and more advanced
Pterodactyloids. A fused clavicle is not needed in
Rhamphorhynchoids because of their smaller size and hence
flight stresses were lessened.
One
obvious difference between Rhamphorhynchoids and
Pterodactyloids is the presence of a long tail in the
Rhamphorhynchoids. The tail includes up to 40 vertebrae and
was cross braced and stiffened by a system of longitudinal
tendons. The function of the tail remains unclear: it
certainly helped the animal steer once airborne but it may
have also helped in counterbalancing the weight of the skull
when the animal was on the ground.
As characterized by all pterosaurs, the wing
membrane is stretched by an elongated fourth finger. The
wrist bones are not fused and the phalanges are longer than
the metacarpals. In the shoulder, the clavicle was not fused
to the sacral vertebrae as in the larger and more advanced
Pterodactyloids. A fused clavicle is not needed in
Rhamphorhynchoids because of their smaller size and hence
flight stresses were lessened.