Data from: What explains patterns of diversification and richness among animal phyla?

Animal phyla vary dramatically in species richness (from one species to
>1.2 million), but the causes of this variation remain largely
unknown. Animals have also evolved striking variation in morphology and
ecology, including sessile marine taxa lacking heads, eyes, limbs, and
complex organs (e.g., sponges), parasitic worms (e.g., nematodes,
platyhelminths), and taxa with eyes, skeletons, limbs, and complex organs
that dominate terrestrial ecosystems (arthropods, chordates). Relating
this remarkable variation in traits to the diversification and richness of
animal phyla is a fundamental yet unresolved problem in biology. Here, we
test the impacts of 18 traits (including morphology, ecology,
reproduction, and development) on diversification and richness of extant
animal phyla. Using phylogenetic multiple regression, the best-fitting
model includes five traits that explain ∼74% of the variation in
diversification rates (dioecy, parasitism, eyes/photoreceptors, a
skeleton, nonmarine habitat). However, a model including just three
(skeleton, parasitism, habitat) explains nearly as much variation (∼67%).
Diversification rates then largely explain richness patterns. Our results
also identify many striking traits that have surprisingly little impact on
diversification (e.g., head, limbs, and complex circulatory and digestive
systems). Overall, our results reveal the key factors that shape
large-scale patterns of diversification and richness across >80% of
all extant, described species.