One species to rule them all: genomics sheds light on the Pocillopora species diversity and distinctiveness around the Arabian Peninsula

Accurate species delimitation and identification are prerequisites for many studies. The common reef-building coral Pocillopora has been extensively studied and used as model species to understand coral biology, physiology, and ecology, but understanding the species diversity and boundaries in this genus has been challenging. In the Arabian region, two species have been generally recognised based on macro-morphology, P. damicornis and P. verrucosa, the latter including two mitochondrial lineages that have recently been considered to represent two cryptic species. Here, using target-capture of ultra-conserved elements and exons, we demonstrate that all these morphs and lineages belong to a single species. Using an integrative approach with genomic, morphological, and geographical lines of evidence, we also show that this species is distinct from other Indo-Pacific species and restricted to the Arabian Peninsula. We resurrect P. favosa Hemprich & Ehrenberg, 1834 for this ecologically important and extensively studied Red Sea Pocillopora species. These results facilitate our understanding of the physiology, biology, and ecology of this major reef coral adapted to the extreme environmental conditions around the Arabian Peninsula.