The Madagascan “Cuckoo-Roller” (Aves: Leptosomidae) is Not a Roller — Notes on the Phylogenetic Affinities and Evolutionary History of a “Living Fossil”

Abstract

The phylogenetic affinities and evolutionary history of the Madagascan Leptosomidae (Courol or “Cuckoo-roller”) are reviewed to rectify erroneous accounts in the recent literature. These birds are not closely related to rollers, and multiple molecular and morphological data sets congruently support their position outside the clade including Coraciiformes sensu stricto (rollers and ground rollers), Piciformes (woodpeckers and allies), and Alcediniformes (kingfishers and allies). The recent discovery that Plesiocathartes, from the Eocene of Europe and North America, is a stem lineage representative of the Leptosomidae further shows that Pan-Leptosomidae were widely distributed across the Northern Hemisphere in the early Paleogene. The Courol is among the few avian taxa which qualify as “living fossils”, and its persistence on Madagascar may have been facilitated by the absence of ecological factors that led to extinction of Pan-Leptosomidae elsewhere.