Museomics unravels cryptic diversity in an endemic group of New Guinean songbirds

Abstract

Deciphering cryptic diversity can have substantial implications for ourunderstanding of evolutionary processes and species conservation. Birdsare arguably among the best studied organismal groups, but even in avianclades there are some genera that have not been thoroughly surveyed.This is particularly true for taxa that occur in hyperdiverse biogeographicregions. In this study, we focus on an endemic group of New Guineanbirds, the jewel-babblers (genus: Ptilorrhoa), and study the diversificationhistory of all known taxa. We assemble a de novo genome using linkedread sequencing and genomic data for 40 historical specimens. Bothphylogenomic and population-genomic analyses strongly support therecovery of a cryptic species and shed new light on the diversificationhistory of this group. The blue jewel-babbler (Ptilorrhoa caerulescens) is aparaphyletic species complex and P. c. nigricrissus is more closely relatedto the phenotypically distinct and sexually dimorphic P. geislerorum, thanto other P. caerulescens subspecies. These findings demonstrate that evenin well-studied groups such as birds, cryptic diversity can still be aprevalent reality. Moreover, by deciphering cryptic diversity, we shed newlight on the processes driving speciation within Ptilorrhoa and the need topotentially revise the taxonomic status of all subspecie