RT info:eu-repo/semantics/article T1 Disentangling ancient interactions: A new extinct passerine provides insights on character displacement among extinct and extant Island finches A1 Rando Reyes, Juan Carlos A1 Alcover, Josep Antoni A1 Illera, Juan Carlos A2 Biología Animal y Edafología y Geología A2 Grupo de investigación: Evoluciónecología y conservación de vertebrados en Macaronesia (VerMac) AB Background: Evolutionary studies of insular biotas are based mainly on extant taxa, although such biotas represent artificialsubsets of original faunas because of human-caused extinctions of indigenous species augmented by introduced exotictaxa. This makes it difficult to obtain a full understanding of the history of ecological interactions between extant sympatricspecies. Morphological bill variation of Fringilla coelebs and F. teydea (common and blue chaffinches) has been previouslystudied in the North Atlantic Macaronesian archipelagos. Character displacement between both species has been argued toexplain bill sizes in sympatry. However, this explanation is incomplete, as similar patterns of bill size have been recorded inF. coelebs populations from islands with and without F. teydea.Methodology/Principal Findings: The discovery of a new extinct species in Tenerife (Canary Islands), here named Carduelisaurelioi n. sp. (slender-billed greenfinch), provides the opportunity to study ancient ecological interactions amongMacaronesian finches. To help understand the evolutionary histories of forest granivores in space and time, we haveperformed a multidisciplinary study combining: (1) morphological analyses and radiocarbon dating (11,460660 yr BP) of thenew taxon and, (2) molecular divergence among the extant finch species and populations in order to infer colonizationtimes (1.99 and 1.09 My for F. teydea and F. coelebs respectively).Conclusion/Significance: C. aurelioi, F. coelebs and F. teydea co-habited in Tenerife for at least one million years. The uniqueanatomical trends of the new species, namely chaffinch-like beak and modified hind and forelimbs, reveal that there was aprocess of divergence of resource competition traits among the three sympatric finches. The results of our study, combinedwith the presence of more extinct greenfinches in other Macaronesian islands with significant variation in their beak sizes,suggests that the character displacement has influenced patterns of divergence in bill size and shape on otherMacaronesian islands as well. YR 2010 FD 2010 LK http://riull.ull.es/xmlui/handle/915/34714 UL http://riull.ull.es/xmlui/handle/915/34714 LA en DS Repositorio institucional de la Universidad de La Laguna RD 24-may-2024