The not-so-great speciator: Systematics and species limits in a rapid radiation, the Asiatic white-eye complex ( Zosterops spp. )

Abstract/Summary Here we untangle the systematics of the Asiatic white-eye complex ( Zosterops spp.) to better understand the early stages of a recent island radiation. We adopt an integrative approach involving allelic data, genome-scale single nucleotide polymorphisms (SNPs), and museum-based morphometrics coupled with a comprehensive sampling to provide the most holistic understanding of the group to date. The island lineages of Asiatic white-eyes across Indonesia, the Philippines, East Asia, the adjacent oceanic islands of the Western Pacific underwent a deep split separating Zosterops everetti and Z. nigrorum in the Phillippines from a very rapid radiation including Z. japonicus , Z. meyeni , and Z. montanus in the Philippines, Japan, and Indonesia. Z. nigrorum catarmanensis on Camiguin South in the Philippines was found to be nested within Z. montanus and a species limit between Z. nigrorum populations on Panay and Luzon was strongly supported. Phylogenetic splits and population structure were detected within the clade containing Z. japonicus , Z. meyeni , and Z. montanus . A well-supported split separates a northern group including Northern Philippines Z. montanus subspecies, Z. meyeni , and Z. japonicus from the southerly Z. montanus taxa. This creates a paraphyletic Z. montanus . However, based on speciation rates within the broader Asiatic white-eye clade this break likely does not yet represent evolutionarily independent species lineages. Morphological evolution is taking place within the Asiatic white-eyes especially within the robust, large-billed subspecies of Z. japonicus on the oceanic islands of Japan and in the newly identified yellow-morph of Z. montanus on Camiguin South.