Historical relationships of three enigmatic phasianid genera (Aves: Galliformes) inferred using phylogenomic and...

The phylogeny of the Phasianidae (pheasants, partridges, and allies) has been studied extensively. However, these studies have largely ignored three enigmatic genera because of scarce DNA source material and limited overlapping phylogenetic data: blood pheasants (Ithaginis), snow partridges (Lerwa), and long-billed partridges (Rhizothera). Thus, phylogenetic positions of these three genera remain uncertain in what is otherwise a well-resolved phylogeny. Previous studies using different data types place Lerwa and Ithaginis in similar positions, but the absence of overlapping data means the relationship between them could not be inferred. Rhizothera was originally described in the genus Perdix (true partridges), although a partial cytochrome b (CYB) sequence suggests it is sister to Pucrasia (koklass pheasant). To identify robust relationships among Ithaginis, Lerwa, Rhizothera, and their phasianid relatives, we used 3692 ultra-conserved element (UCE) loci and complete mitogenomes from 19 species including previously hypothesized relatives of the three focal genera and representatives from all major phasianid clades. We used DNA extracted from historical specimen toepads for species that lacked fresh tissue in museum collections. Maximum likelihood and multispecies coalescent UCE analyses strongly supported Lerwa sister to a large clade which included Ithaginis at its base, and also including turkey, grouse, typical pheasants, tragopans, Pucrasia, and Perdix. Rhizothera was also in this clade, sister to a diverse group comprising Perdix, typical pheasants, Pucrasia, turkey and grouse. Mitogenomic genealogies differed from UCEs topologies, supporting a sister relationship between Ithaginis and Lerwa rather than a grade. The position of Rhizothera using mitogenomes depended on analytical choices. Unpartitioned and codon-based analyses placed Rhizothera sister to a tragopan clade, whereas a partitioned DNA model of the mitogenome was congruent with UCE results. In all mitogenome analyses, Pucrasia was sister to a clade including Perdix and the typical pheasants with high support, in contrast to UCEs and published nuclear intron data. Due to the strong support and consistent topology provided by all UCE analyses, we have identified phylogenetic relationships of these three enigmatic, poorly-studied, phasianid taxa.