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Pelvic spurs (also known as vestigial legs) are external protrusions found around the cloaca in certain superfamilies of snakes belonging to the greater infraorder Alethinophidia. [1] These spurs are made up of the remnants of the femur bone, which is then covered by a corneal spur, or claw-like structure. [ 1 ]
Eupodophis is an extinct genus of snake from the Late Cretaceous period. It has two small hind legs and is considered a transitional form between Cretaceous lizards and limbless snakes. The feature, described as vestigial, was most likely useless to Eupodophis. [1]
Early snakes had vestigial limbs, with the oldest-known fully limbless snake living around 85 million years ago, according to George Washington University evolutionary biologist and study co ...
The cardiovascular system of snakes is unique for the presence of a renal portal system in which the blood from the snake's tail passes through the kidneys before returning to the heart. [79] The circulatory system of a snake is basically like those of any other vertebrae. However, snakes do not regulate internally the temperature of their blood.
Based on comparative anatomy, there is consensus that snakes descended from lizards. [10]: 11 [11] Pythons and boas—primitive groups among modern snakes—have vestigial hind limbs: tiny, clawed digits known as anal spurs, which are used to grasp during mating.
The North American kangaroo rat, Australian hopping mouse, and North African and Asian jerboa have developed convergent adaptations for hot desert environments; these include a small rounded body shape with large hind legs and long thin tails, a characteristic bipedal hop, and nocturnal, burrowing and seed-eating behaviours. These rodent groups ...
Both families share a number of primitive characteristics. Nearly all have a relatively rigid lower jaw with a coronoid element, as well as a vestigial pelvic girdle with hind limbs that are partially visible as a pair of spurs, one on either side of the vent. In males, these anal spurs are larger and more conspicuous than in females. A long ...
Species in the family Anomalepididae are small snakes, in total length (including tail) usually less than 30 cm (12 in), with blunt heads and short, blunt tails. They are mainly burrowing snakes, and due to their life style their eyes are vestigial.