= Amphisbaenian
An <amphisbaenian> is a member of Amphisbaenia, a lineage of predominantly burrowing <Squamata>. The elongated body often has rings of scales, small eyes and a skull specialized for moving through soil. Most species lack external limbs, but <Bipes> retains forelimbs. Their wormlike appearance does not make them <Annelida>, and a limbless body does not make them <snakes>.
Their evolutionary relationships illustrate the problem of <convergent evolution>. Burrowing can favor similar reductions and skull modifications in separate reptile lineages, making an anatomy-only grouping misleading. An integrated 2015 study compared morphological characters, molecular sequences and <fossil> taxa, and recovered amphisbaenians with lacertids in <Lacertoidea>. Including <DNA> allowed the investigators to test similarities that might instead reflect similar modes of life.<Integrated Analyses Resolve Conflicts over Squamate Reptile Phylogeny and Reveal Unexpected Placements for Fossil Taxa by Tod W. Reeder and others>[Results and Discussion, Lacertoidea and convergent burrowing morphology]{ref}
The example shows why a shared loss of limbs must be interpreted on a <phylogenetic tree>, alongside other evidence, before it is treated as evidence of close ancestry.
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