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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 ]
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.
Large, well-developed limbs increase drag on swimming animals, so the limbs of Eupodophis and other early snakes may have become vestigial to save energy and make movement more efficient. No vestigial limbs whatsoever are present in the modern species, which lack transitional species remnants. What few species have them protrude as tiny spurs.
X-ray showing the skeleton of Typhlonectes (Typhlonectidae). Caecilians' anatomy is highly adapted for a burrowing lifestyle. In a couple of species belonging to the primitive genus Ichthyophis vestigial traces of limbs have been found, and in Typhlonectes compressicauda the presence of limb buds has been observed during embryonic development, remnants in an otherwise completely limbless body. [7]
The term spur is sometimes used to describe the pelvic spur, vestigial limbs found in primitive snakes, such as boas and pythons and in the striped legless lizard. [3] [4] The spurs primarily serve as holdfasts during mating. As these form at the terminal end of the limb, they may properly be claws rather than true spurs.
Tiny worms behave more like snakes. Research on the worms began more than 15 years ago at Sam Houston State University when Patrick J. Lewis, a professor there, led a research trip to Botswana ...
Based on genomic analysis it is certain that snakes descend from lizards. [23] This conclusion is also supported by comparative anatomy, and the fossil record. [26]: 11 [27] [23] 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.
PhD student reassures snakes found in walls and roofs in Wales are completely harmless to humans.