Phenotypic evolution of an Atlantic Forest passerine (Xiphorhynchus fuscus): biogeographic and systematic implications

Abstract

We studied the phenotypic variation of the Atlantic Forest passerine Xiphorhynchus fuscus (Aves: Dendrocolaptidae) with the broad aim of addressing whether the history and type of forest affected the evolution of endemic taxa. We also tested whether the different subspecies and genetic lineages of X. fuscus could be considered full species. We collected plumage and body size measurements and, in combination with genetic data, used multivariate tests to evaluate the working hypotheses. Our results, combined with previous biogeographic analyses, indicate that vicariant events have been important determinants in the evolution of phenotypic characters of X. fuscus, once genetic isolation was complete. Our analysis also suggests that forest heterogeneity and ecotones are important factors in the early evolution of Atlantic Forest taxa, perhaps via divergent selection. Forest instability during the Pleistocene was critical in the evolution of phenotypic traits. We confirm that the subspecies atlanticus should be considered a full species. Other lineages or populations are also phenotypically differentiated but we do not suggest considering them as full species. They share high levels of gene flow and are part of a continuous latitudinal cline of phenotypic variation. Our study suggests that not all the historic events in the Atlantic Forest that affected the evolution of genetic lineages also influenced the evolution of phenotypic characters in the same direction and intensity. Undoubtedly, natural selection played a major role in the evolution of Atlantic Forest organisms.

Historical relationships of areas of endemism of the Brazilian Atlantic rain forest: a cladistic biogeographic analysis of harvestman taxa (Arachnida: Opiliones)

“…The importance of the Doce River and Todos os Santos Bay disjunctions are corroborated by many studies using different methods and taxa ( Müller 1973 ; Prance 1982 ; Amorim and Pires 1996 ; Silva et al 2004 ; Pellegrino et al 2005 ; Sigrist and Carvalho 2009 ; Brunes et al 2010 ; Thomé et al 2010 ; Silva et al . 2012 ; Cabanne et al 2014 ); the latter has also been associated with the São Francisco River ( Carnaval and Moritz 2008 ). DaSilva et al (2015) provided detailed geographical and historical information on the barriers between areas of endemism for harvestmen and also showed that the Todos os Santos Bay should receive more attention from biogeographers, because it is more closely associated with the range limits of endemic species (see also Amorim and Pires [1996 ] and Silva et al [2012 ]).…”

“…Since the Neogene period, these characteristics allowed for a greater reduction of the forests in these regions because of climatic fluctuations that would cause feedback to facilitate their instability. This model of diversification of reiterative barriers with spatial congruence at multiple times would respond to claims of individual taxa history when it is shown that different taxa diverge at different times in the same barrier ( Brunes et al 2010 ; Thomé et al 2010 ; Cabanne et al 2014 ). This represents an argument against pseudo-congruence ( Donoghue and Moore 2003 ).…”

“…It corresponds to the Atlantic biogeographical province of the Parana dominion ( Morrone 2014a , 2014b ). In the last few years, several phylogeographical studies of this area’s species have been published ( Pellegrino et al 2005 ; Grazziotin et al 2006 ; Carnaval et al 2009 ; Fitzpatrick et al 2009 ; Martins et al 2009 ; Mata et al 2009 ; Batalha-Filho et al 2010 ; Thomé et al 2010 ; D’Horta et al 2011 ; Amaro et al 2012 ; Amaral et al 2013 ; Fusinatto et al 2013 ; Valdez and D’elía 2013 ; Cabanne et al 2014 ; Dantas et al 2015 ). Even though these studies have identified disjunctions within the forest biota, they were not intended to formulate explicit hypotheses on area relationships within the Atlantic Forest.…”

Spatial predictors of genomic and phenotypic variation differ in a lowland Middle American bird (Icterus gularis)

“…Without knowledge of the exact genomic basis and heritability of these traits, it is difficult to precisely determine which forces have shaped phenotypic variation (Mitchell_Olds et_al.,_2007). However, when combined with genome_wide genetic data, phenotypic information can provide insight into which mechanisms might have played a role in driving the origins of phenotypic variation (Cabanne, Trujillo_Arias, Calder_n, D_Horta, & Miyaki,_2014; Rausher & Delph,_2015). For example, if geographical patterns of phenotypic variation coincide closely with historical barriers to dispersal (IBH) or change clinally with geographical distance (IBD), phenotypic differences among populations might have evolved primarily as a byproduct of genetic drift, potentially reinforced by natural selection across the barrier or along the cline (Lande,_1980).…”

“…Without knowledge of the exact genomic basis and heritability of these traits, it is difficult to precisely determine which forces have shaped phenotypic variation (Mitchell-Olds et al, 2007). However, when combined with genome-wide genetic data, phenotypic information can provide insight into which mechanisms might have played a role in driving the origins of phenotypic variation (Cabanne, Trujillo-Arias, Calderón, D'Horta, & Miyaki, 2014;Rausher & Delph, 2015).…”