Comparative species divergence across eight triplets of spiny lizards (Sceloporus) using genomic sequence data.

Species divergence is typically thought to occur in the absence of gene flow, but many empirical studies are discovering that gene flow may be more pervasive during species formation. Although many examples of divergence with gene flow have been identified, few clades have been investigated in a comparative manner, and fewer have been studied using genome-wide sequence data. We contrast species divergence genetic histories across eight triplets of North American Sceloporus lizards using a maximum likelihood implementation of the isolation-migration (IM) model.

Developmental mode influences diversification in ascidians.

Ascidian species (Tunicata: Ascidiacea) usually have tailed, hatching tadpole larvae. In several lineages, species have evolved larvae that completely lack any tail tissues and are unable to disperse actively. Some tailless species hatch, but some do not hatch before going through metamorphosis.