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| Atlantisia rogersi Lowe, 1923
in Stervander, Ryan, Melo & Hansson, 2018.
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Highlights
• Atlantisia rogersi colonized Inaccessible Island from S. America 1.5 million years ago.
• Its closest relative is the Dot-winged Rail Porzana spiloptera.
• The well-supported clade also contains Black Rail Laterallus jamaicensis.
• We advise conservative taxonomic changes: Laterallus rogersi, L. spilopterus.
• Further sampling of the ‘Laterallus clade’ required for a fully resolved phylogeny.
Abstract
Rails (Aves: Rallidae) are renowned for their extreme dispersal capability, which has given rise to numerous island lineages. Many insular species lost the ability to fly as a response to release from predator pressure—a feature causing rapid extinction when humans subsequently introduced mammals. The world’s smallest extant flightless bird, the Inaccessible Island Rail Atlantisia rogersi, is endemic to Inaccessible Island, Tristan da Cunha archipelago, in the central South Atlantic Ocean. It is placed in a monotypic genus, but its taxonomic affinity, as well as geographic origin, are disputed. Contrary to its suggested Old World origin, we demonstrate that the Inaccessible Island Rail is nested within the mainly South American ‘Laterallus clade’ and that it colonized ≥3 million-year-old Inaccessible Island from South America c. 1.5 million years ago. The taxonomy of rails has traditionally been based on morphology, and convergent evolution has caused many cases of misclassification. We suggest a re-classification within the ‘Laterallus clade’ and call for extended coverage of taxon sampling for DNA sequencing.
Keywords: Colonization, Oceanic islands, Phylogeny, Phylogeography, Taxonomy
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| Fig. 1. (A) Map showing the location of Inaccessible Island of the Tristan da Cunha archipelago, and distances to continents and islands (the latter not drawn to scale). The approximate range of Dot-winged Crake Porzana spiloptera, sister species of the Inaccessible Island Rail Atlantisia rogersi, is shown with grey shading. |
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| Fig. 1. (B) Inaccessible Island Rail Atlantisia rogersi (photo: P.G.R.). (C) Dot-winged Crake Porzana spiloptera (photo: Alec Earnshaw). (D) Black Rail Laterallus jamaicensis, which is sister to B and C (photo: Chuck Streker). (E) Galápagos Crake Laterallus spilonota (photo: Jaime Chaves), which is presumed to belong to the same clade as B–D. |
Martin Stervander, Peter G. Ryan, Martim Melo and Bengt Hansson. 2018. The Origin of the World’s Smallest Flightless Bird, the Inaccessible Island Rail Atlantisia rogersi (Aves: Rallidae). Molecular Phylogenetics and Evolution. 130; 92-98. DOI: 10.1016/j.ympev.2018.10.007
