Raw target enrichment of conserved element sequence data for 24 black coral species

Deep-sea lineages are generally thought to arise from shallow-water
ancestors, but this hypothesis is based on a relatively small number of
taxonomic groups. Anthozoans, which include corals and sea anemones, are
significant contributors to the faunal diversity of the deep sea, but the
timing and mechanisms of their invasion into this biome remain elusive.
Here, we reconstruct a fully resolved, time-calibrated phylogeny of 83
species in the order Antipatharia (black coral) to investigate their
bathymetric evolutionary history. Our reconstruction indicates that extant
black coral lineages first diversified in continental slope depths
(~250–3,000 m) during the early Silurian (~437 Ma) and subsequently
radiated into, and diversified within, both continental shelf (<250
m) and abyssal (>3,000 m) habitats. Ancestral state reconstruction
analysis suggests that the appearance of morphological features that
enhanced the ability of black corals to acquire nutrients coincided with
their invasion of novel depths. Our findings have important conservation
implications for anthozoan lineages, as the loss of “source” slope
lineages could threaten millions of years of evolutionary history and
confound future invasion events, thereby warranting protection.