Data from: Vertebral evolution and the diversification of squamate reptiles

Taxonomic, morphological and functional diversity are often discordant and
independent components of diversity. A fundamental and largely unanswered
question in evolutionary biology is why some clades diversify primarily in
some of these components and not others. Dramatic variation in trunk
vertebral numbers (14 to >300) among squamate reptiles coincides
with different body shapes, and snake-like body shapes have evolved
numerous times. However, whether increased evolutionary rates or numbers
of vertebrae underlie body shape and taxonomic diversification is unknown.
Using a supertree of squamates including 1375 species, and corresponding
vertebral and body shape data, we show that increased rates of evolution
in vertebral numbers have coincided with increased rates and disparity in
body shape evolution, but not changes in rates of taxonomic
diversification. We also show that the evolution of many vertebrae has not
spurred or inhibited body shape or taxonomic diversification, suggesting
that increased vertebral number is not a key innovation. Our findings
demonstrate that lineage attributes such as the relaxation of constraints
on vertebral number can facilitate the evolution of novel body shapes, but
that different factors are responsible for body shape and taxonomic
diversification.