Dispersals from the West Tethys as the source of the Indo-West Pacific diversity hotspot in comatulid crinoids

Abstract Conspicuous centers of biodiversity are frequently attributed to local conditions that promote speciation or resistance extinction, but recent diversification studies indicate this mode explanation might not be very general, so it may fruitful revisit the role dispersal in concentrating biodiversity. Here we consider processes underlying marine diversity hotspot Indo-West Pacific among comatulid crinoids, suspension-feeding echinoderms conspicuous on modern tropical reefs. We used ancestral-range reconstruction a phylogeny extant assembled new occurrence database fossil comatulids and interrogated with probabilistic preservational models, developed morphological character matrix estimate relationships living comatulids. Ancestral-range recovers an origin outside Indo-Pacific elevated into it. A records clade spreading out gradually from Early Jurassic West Tethys. Comatulids do appear their until Oligocene, taphonomic analyses show these results cannot explained solely as result inadequate sampling Asia Oceania. Finally, phylogenetic demonstrate deeply nested crown-group had originated before became well established East Tethys, implying many independent dispersals hotspot. These consilient suggest owes its existence ancient Tethys rather than situ diversification.