Phylogenomic resolution of lampreys reveals the recent evolution of an ancient vertebrate lineage

Jawless vertebrates once dominated Paleozoic waters, but just two lineages
persisted to the present day: lampreys and hagfishes. Living lampreys are
a relatively small clade, with just over fifty species described, but
knowledge of their evolutionary relationships has always been based on
either a few mitochondrial genes or a small number of taxa. Biogeographers
have noted the disjunct antitropical distribution of living lamprey
families. Here we present a comprehensive phylogenomic analysis of living
and fossil lampreys, sampling 36 species with phylogenomic data and 46 in
total with genetic data. We present new divergence time estimates based on
comprehensive nuclear data and analysis of their diversification dynamics.
Our analysis indicates a central role for extreme global warming during
the Late Cretaceous Cenomanian-Turonian Boundary Event as a likely cause
for the antitropical distribution of living lampreys, and a notable
increase in lineage diversification in northern hemisphere lampreys during
the Miocene corresponding with a period of global cooling.