RESUMEN
The targeted capture of ultraconserved elements (UCEs) has substantially increased the amount of genetic data available for phylogenomic reconstructions. These capture datasets frequently contain mitochondrial DNA as a by-product, often in the form of complete mitogenomes. These can be efficiently harvested to expand existing datasets without additional costs. Here, we present new mitochondrial genomes for six marine angelfish species (F: Pomacanthidae), assembled and annotated from off-target UCE reads. We provide the first comparative analysis of all mitochondrial genomes available for the Pomacanthidae. Results showed that the average length of pomacanthid mitogenomes is 16.8 kbp. Total GC and AT content varied between 44.5% and 46.3%, and 53.7% and 55.5%, respectively. The architecture of angelfish mitogenomes was comparable to that seen in other fish species with 13 protein-coding genes (PCGs), 22 transfer RNA genes, two ribosomal RNA genes and the control region. All 13 PCGs evolved under purifying selection, highlighting a high level of selection pressure and gene expression to preserve genetic integrity. The ND6 and ATP8 genes had the highest ratio of non-synonymous (dN) to synonymous (dS) substitutions, indicating a relaxation of purifying selection constraints. Finally, these newly assembled mitogenomes will allow further investigations of the population genetics, systematics and evolutionary biology of one of the most prominent reef fish family in the aquarium trade.
RESUMEN
Marine angelfishes (F: Pomacanthidae) are amongst the most conspicuous reef fish families inhabiting reefs on tropical and subtropical latitudes. While being disproportionately represented in the marine ornamental fish trade, only a handful of taxonomically restricted studies explored their biogeographic history and the evolution body size and trophic guilds. Here, we reconstruct the phylogenetic history for 70 pomacanthid species (85% of nominal species), based on previously published data for three nuclear and four mitochondrial markers. We use the resulting phylogenetic framework to explore the ancestral biogeography and ecological diversification of the family. Divergence times and ancestral range estimation highlight the origins of the family most likely lie in the Central Pacific region. Vicariance among ocean basins reflects the impact of the Terminal Tethyan Event and the closure of the Isthmus of Panama in the historical biogeography of Pomacanthus and Holacanthus genera. The reconstruction also uncovers ancestral colonization pathways via the Pacific Ocean into the western Atlantic waters for Holacanthus. We confirm the Indian Ocean invasion scenario previously proposed for the "acanthops" complex (genus: Centropyge). Finally, interspecific variation in body size among clades appeared to be correlated to some degree with trophic guilds, whereby 15% of variance in body size was explained by trophic modes. This suggests that the higher ecological diversification observed in the Centropyge clade might be promoted by smaller body sizes acting as an ecological novelty allowing the expansion of the genus within available niches.
