Modified Subfossil Aye-Aye Incisors from Southwestern Madagascar: Species Allocation and Paleoecological Significance

Two of the three drilled aye-aye incisors collected in 1901 by Grandidier at the subfossil site of Lamboharana were recently rediscovered in uncatalogued collections of the Institut de Paléontologie in Paris. These teeth are not much wider or thicker than those of the extant aye-aye (Daubentonia madagascariensis), but their arc of curvature is noticeably greater. These facts indicate that the teeth probably belong to D. robusta, a large extinct aye-aye whose dentition is otherwise unknown. No other remains referable to Daubentonia have been reported from Lamboharana, although D. robusta is known from other localities in the southwest. The presence of Daubentonia in southern Madagascar does not demonstrate that this region was markedly more humid or densely forested in the recent past. It remains to be established whether the extinction of D. robusta throughout its range in southern Madagascar, and local disappearance of D. madagascariensis everywhere but in the eastern forest biotope, is due to late Holocene climatic change, to anthropogenic effects, or both factors combined.