The Sulawesi Thrush (Cataponera turdoides; Aves: Passeriformes) belongs to the genus Turdus

The Asian and Australo-Papuan faunas meet and intermix across the islands of Wallacea. Untangling the origins and relationships of the species inhabiting these archipelagos is an ongoing project that has lasted for well over a century. In recent years, molecular phylogenetic studies have made considerable progress in clarifying the affinities of enigmatic Wallacean taxa, but taxonomic riddles remain, even in groups as well studied as birds. Such is the case with Sulawesi Thrush Cataponera turdoides, a scarce and elusive montane songbird whose taxonomic placement has remained controversial since its description. To determine the evolutionary relationships of this monotypic genus, we obtained a museum specimen and employed whole-genome resequencing to generate a multi-locus dataset. Phylogenetic analyses were performed using UCEs, and individual mitochondrial and nuclear genes. We show that Cataponera is a true thrush of the large and geographically widespread genus Turdus. It belongs to a clade predominantly composed of migratory Palearctic species, but has no close relatives within that group. Sulawesi Thrush is one of only two members of the genus Turdus known to have crossed Wallace's Line to form resident populations.

Automated summary

The Wallace Line area is the convergence zone of the Asian and Australo-Papuan faunas, and studying the origins and relationships of species here has been ongoing for over a century. Despite considerable progress in clarifying the affinities of Wallacean taxa, taxonomic puzzles still exist, as seen in the case of the Sulawesi Thrush.