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![Phylogenetic tree for Pionopsitta parrots obtained in a maximum likelihood analysis of the 2168 bp ATPase + COI + cyt b dataset. A topologically identical tree was obtained in a Bayesian analysis, and an exhaustive parsimony search found a single most parsimonious tree with the same topology. Values above the nodes are maximum likelihood bootstrap values (100 replicates); values below the nodes are Bayesian posterior probability values, followed by parsimony bootstrap values (1000 replicates). The phylogenetic position of P. [b.] barrabandi according to the COI data is indicated with a dotted line (see text). Nodes are color-coded to correspond with Figs. 5–7.](profile/Jessica-Eberhard-2/publication/7786357/figure/fig3/AS:340776887308304@1458258949794/Phylogenetic-tree-for-Pionopsitta-parrots-obtained-in-a-maximum-likelihood-analysis-of.png)
Phylogenetic tree for Pionopsitta parrots obtained in a maximum likelihood analysis of the 2168 bp ATPase + COI + cyt b dataset. A topologically identical tree was obtained in a Bayesian analysis, and an exhaustive parsimony search found a single most parsimonious tree with the same topology. Values above the nodes are maximum likelihood bootstrap values (100 replicates); values below the nodes are Bayesian posterior probability values, followed by parsimony bootstrap values (1000 replicates). The phylogenetic position of P. [b.] barrabandi according to the COI data is indicated with a dotted line (see text). Nodes are color-coded to correspond with Figs. 5–7.
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Studies of Neotropical birds, and their distributions and areas of endemism, in particular, have been central in the formulation of hypotheses proposed to explain the high species diversity in the Neotropics. We used mtDNA sequence data (ATPase 6 and 8, COI, and cyt b) to reconstruct the species-level phylogenies for two genera, Pionopsitta (Aves:...
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Context 1
... analysis of the 2168 bp ATPase + COI + cyt b Pionopsitta dataset yielded trees with identical topologies, regardless of the reconstruction algorithm used. The ML tree shown in Fig. 3 is topologically identical to the single tree found in an exhaustive parsimony search, and is also identical to the Bayesian tree, as well as neighbor-joining trees reconstructed using a variety of distance corrections (not shown). Bootstrap and posterior probability values show high support for all nodes. Pionopsitta pileata, from the ...
Context 2
... early in the history of the genus. Pionopsitta [Gypopsitta] vulturina falls well within the genus Pionopsitta, and is sister to P. caica. Since only a COI sequence was obtained for the P. b. barrabandi sample, it could not be included in the ATPase + COI + cyt b dataset, but its position according to analysis of the COI data is indicated in Fig. 3. In phylogenies reconstructed using only the COI data (not shown), the node connecting P. b. barrabandi and P. b. aurantiigena is well-supported in bootstrap analyses (96 and 98% for neighbor-joining and parsimony trees, respectively), and the taxa show 1.5% sequence divergence in ...
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The range of the grey parrot (Psittacus erithacus), one of the most heavily harvested bird species for the international pet trade, spans the forest belt of Central and West Africa and includes the oceanic island of Príncipe (Gulf of Guinea). Morphological variation led to the recognition of two mainland subspecies (P. e. erithacus and P. e. timneh...
Citations
... Andean mountain ranges are important contributors to the diversification of Neotropical lowland birds (Brumfield and Capparella 1996, Brumfield and Edwards 2007, Miller et al. 2008, Milá et al. 2012. Still, their effect as strong barriers has been debated across avian studies (Eberhard and Bermingham 2005, DaCosta and Klicka 2008, Ribas et al. 2009, Patel et al. 2011, d'Horta et al. 2013, Hazzi et al. 2018. ...
... First, the uplift of the Andes served as a vicariance event driving the diversification of the clades on either side of the Andes (Graham et al. 2009, Patel et al. 2011, d'Horta et al. 2013, Fernandes et al. 2014. Second, dispersal during the uplift was likely followed by isolation and speciation; the dispersal may have occurred around the northern Andes through the Caribbean lowlands or lowlying passes through the Andes (Eberhard and Bermingham 2005, Miller et al. 2008, Ribas et al. 2009. Several low-lying passes have been identified in the northern Andes across which avian lineages may have dispersed . ...
We examined phylogeographic patterns and cryptic diversity within the royal flycatcher, Onychorhynchus coronatus (Aves: Onychorhynchidae), a widespread Neotropical lowland forest tyrant flycatcher. A phylogeny of the six recognized subspecies was constructed from mtDNA sequence data of the NADH dehydrogenase subunit two gene, using Bayesian Inference and Maximum Likelihood methods. Phylogenetic analyses revealed high levels of intraspecific divergence within O. coronatus, supporting the existence of at least six independent lineages. The phylogenetic results uncovered the following relationships: (O. c. swainsoni [Southern Atlantic Forest], (O. c. coronatus [western Amazonia], (O. c. castelnaui [eastern Amazonia], (O. c. mexicanus [Central America], (O. c. occidentalis [Tumbesian], O. c. fraterculus [extreme northwestern South America])))). Biogeographic and dating analyses suggest that vicariant and dispersal events acted across approximately six million years to influence lineage diversification within this genus. Some of those events include the formation of the Amazon River and its tributaries, Andean uplift, and climatically induced vegetational shifts. Phylogenetic and biogeographic analyses of O. coronatus lineages support a hypothesis of area relationships in which the first divergence event isolated the Southern Atlantic Forest from Amazonia during the Late Miocene/Early Pliocene. This event was followed by the split of western and eastern Amazonia at the Early/Late Pliocene, the divergence of cis‐ and trans‐Andean lowland regions also at the Early/Late Pliocene, the split between Central America and the extreme northwestern South America/Tumbes at the Early/Middle Pleistocene, and the split between extreme northwestern South America and Tumbes at Middle/Late Pleistocene. Subsequent divergence of the southern and northern populations in the western and eastern Onychorhynchus lineages took place during the Pleistocene. Comparison of phylogenetic trees and patterns in Onychorhynchus with those from published work suggests that across large New World radiations such as the Suboscines, some co‐distributed lineages began to diverge long before others, which exemplifies the complexity of their evolutionary history.
... Despite this group's clear utility for testing hypotheses about replicate biogeographic histories of co-distributed genera across the Neotropics, precise phylogenetic relationships among species, genera, and families of toucans, toucanbarbets, and New World barbets have yet to be resolved. Studies have either reconstructed higher-level relationships among genera and families (Lanyon and Zink 1987, Barker and Lanyon 2000, Moyle 2004), focused on species-level phylogenies within genera (Hackett and Lehn 1997, Weckstein 2005, Eberhard and Bermingham 2005, Puebla-Olivares et al. 2008, Patané et al. 2009, Bonaccorso et al. 2011, Patel et al. 2011, Lutz et al. 2013, or focused on one species complex (Armenta et al. 2005). All previous studies have been based on either morphological characters (Cracraft and Prum 1988, Prum 1988a, Prum 1988b, allozymes (Lanyon and Zink 1987), or Sanger DNA sequences from only a few mitochondrial or nuclear loci (Hackett and Lehn 1997, Barker and Lanyon 2000, Moyle 2004, Weckstein 2005, Eberhard and Bermingham 2005, Puebla-Olivares et al. 2008, Patané et al. 2009, Bonaccorso et al. 2011, Patel et al. 2011, Lutz et al. 2013. ...
... Studies have either reconstructed higher-level relationships among genera and families (Lanyon and Zink 1987, Barker and Lanyon 2000, Moyle 2004), focused on species-level phylogenies within genera (Hackett and Lehn 1997, Weckstein 2005, Eberhard and Bermingham 2005, Puebla-Olivares et al. 2008, Patané et al. 2009, Bonaccorso et al. 2011, Patel et al. 2011, Lutz et al. 2013, or focused on one species complex (Armenta et al. 2005). All previous studies have been based on either morphological characters (Cracraft and Prum 1988, Prum 1988a, Prum 1988b, allozymes (Lanyon and Zink 1987), or Sanger DNA sequences from only a few mitochondrial or nuclear loci (Hackett and Lehn 1997, Barker and Lanyon 2000, Moyle 2004, Weckstein 2005, Eberhard and Bermingham 2005, Puebla-Olivares et al. 2008, Patané et al. 2009, Bonaccorso et al. 2011, Patel et al. 2011, Lutz et al. 2013. Consequently, many relationships among genera, families, and species are uncertain. ...
... Ramphastos toco was identified as sister to all other Ramphastos toucans (Weckstein 2005). Two lowland toucan genera, Ramphastos toucans and Pteroglossus araçaris, have relatively low genetic divergence (Hackett and Lehn 1997, Eberhard and Bermingham 2005, Patel et al. 2011, Weckstein 2005, Patané et al. 2009). Conversely, Aulacorhynchus harbors underappreciated genetic divergence and geographic variation. ...
We reconstruct the species-level phylogenetic relationship among toucans, toucan-barbets, New World barbets using phylogenomic data to assess the monophyly and relationships at the family, generic, and specific levels. Our analyses confirmed (1) the monophyly of toucans (Aves: Ramphastidae), toucan-barbets (Aves: Semnornithidae), and New World barbets (Aves: Capitonidae) and that the toucan-barbets are sister to the toucans, an arrangement suggested, but poorly supported, in previously published phylogenies; (2) the paraphyly of lowland Selenidera toucanets with respect to Andigena mountain-toucans; and (3) evidence of some mitonuclear discordance, suggesting introgression or incomplete lineage sorting. For example, mitonuclear conflict in the phylogenetic placement of Ramphastos vitellinus subspecies suggests that Amazonian populations of Ramphastos vitellinus ariel may have introgressed mitogenomes derived from other Amazonian vitellinus taxa. To reconstruct the phylogenetic history of toucans, toucan-barbets, and New World barbets, we included all species-level taxa from the three families, with the addition of outgroups from the two major clades of Old World barbets (Megalaimidae and Lybiidae). We analyzed a combination of UCE sequences and whole mitochondrial genome sequences to reconstruct phylogenetic trees.
... The first major phylogeographic break for Makalata was estimated at approximately 6.28 Mya at the Late Miocene by dispersal followed by vicariance, implying an east-west Amazonian distribution pattern ( Fig 4B and Table 2). A similar biogeographic pattern has been found for other wildlife groups, such as lizards [77,[89][90][91][92][93], amphibians [94]; birds [95,96] and mammals [44,97]. ...
Amazonian mammal diversity is exceptionally high, yet new taxonomic discoveries continue to be made and many questions remain for understanding its diversification through time and space. Here we investigate the diversification of spiny rats in the genus Makalata , whose species are strongly associated with seasonally flooded forests, watercourses and flooded islands. We use a biogeographical approach based on a mitochondrial cytochrome b gene through divergence time estimation and reconstruction of ancestral areas and events. Our findings indicate an ancient origin of Makalata for the Guiana Shield and Eastern Amazonia as ancestral area. A first cladogenetic event led to a phylogeographic break into two broader clades of Makalata through dispersal, implying a pattern of western/Eastern Amazonian clades coinciding with the Purus Arch (middle Miocene). Most of subclades we infer originated between the late Pliocene to the early Pleistocene, with few recent exceptions in the early Pliocene through dispersal and vicariant events. The hypothesis of rivers as dispersal barriers is not corroborated for Makalata , as expected for mammalian species associated with seasonally flooded environments. We identify two key events for the expansion and diversification of Makalata species: the presence of geologically stable areas in the Guiana and Brazilian shields and the transition from lacustrine conditions in western Amazonia (Acre system) to a river system, with the establishment of the Amazon River transcontinental system and its tributaries. Our results are congruent with older geological scenarios for the Amazon basin formation (Miocene), but we do not discard the influence of recent dynamics on some speciation events and, mainly, on phylogeographic structuring processes.
... Mya), possibly related to climatic oscillations [100]. In what now comprises the genera Pionopsitta and Pyrilia, however, diversification was attributed more to geotectonic events and river dynamics between 8.7 and 0.6 Mya than to glacial cycles [101,102]. A study on Pionus spp. ...
Parrots (Psittaciformes) are a well-studied, diverse group of birds distributed mainly in tropical and subtropical regions. Today, one-third of their species face extinction, mainly due to anthropogenic threats. Emerging tools in genetics have made major contributions to understanding basic and applied aspects of parrot biology in the wild and in captivity. In this review, we show how genetic methods have transformed the study of parrots by summarising important milestones in the advances of genetics and their implementations in research on parrots. We describe how genetics helped to further knowledge in specific research fields with a wide array of examples from the literature that address the conservation significance of (1) deeper phylogeny and historical biogeography; (2) species- and genus-level systematics and taxonomy; (3) conservation genetics and genomics; (4) behavioural ecology; (5) molecular ecology and landscape genetics; and (6) museomics and historical DNA. Finally, we highlight knowledge gaps to inform future genomic research on parrots. Our review shows that the application of genetic techniques to the study of parrot biology has far-reaching implications for addressing diverse research aims in a highly threatened and charismatic clade of birds.
... (1,735 bp). The mitochondrial genes were amplified using primers L5215 (5'-TATCGGGCCCATACCCCGAAAAT-3') (Hackett 1996) and H6313 (5'-CTCTTATTTAAGGCTTTGAAGGC-3') (Sorenson et al. 1999) for nad2 and L8929 (5'-GGACAATGCTCAGAAATCTCGCGG-3') (Eberhard and Bermingham 2005) and ...
Oceanic archipelagos are excellent systems for studying speciation, yet inference of evolutionary process requires that the colonization history of island organisms be known with accuracy. Here, we used phylogenomics and patterns of genetic diversity to infer the sequence and timing of colonization of Macaronesia by mainland common chaffinches (Fringilla coelebs), and assessed whether colonization of the different archipelagos has resulted in a species-level radiation. To reconstruct the evolutionary history of the complex we generated a molecular phylogeny based on genome-wide SNP loci obtained from genotyping-by-sequencing, we ran ancestral range biogeographic analyses, and assessed fine-scale genetic structure between and within archipelagos using admixture analysis. To test for a species-level radiation, we applied a probabilistic tree-based species delimitation method (mPTP) and an integrative taxonomy approach including phenotypic differences. Results revealed a circuitous colonization pathway in Macaronesia, from the mainland to the Azores, followed by Madeira, and finally the Canary Islands. The Azores showed surprisingly high genetic diversity, similar to that found on the mainland, and the other archipelagos showed the expected sequential loss of genetic diversity. Species delimitation methods supported the existence of several species within the complex. We conclude that the common chaffinch underwent a rapid radiation across Macaronesia that was driven by the sequential colonization of the different archipelagos, resulting in phenotypically and genetically distinct, independent evolutionary lineages. We recommend a taxonomic revision of the complex that takes into account its genetic and phenotypic diversity.
... The timing of the Amazonian and Atlantic Forest split within the Megascops atricapilla-M. watsonii complex was similar to the splits documented for Ramphastos Linnaeus (0.77-1.4 mya; Patané et al. 2009) and Pionus Wagler (0.15-1.41 mya; Ribas et al. 2007), and younger than the timing of these same biogeographic splits for taxa such as Brotogeris Vigors (Ribas et al. 2009), Xiphorhynchus Swainson (Cabanne et al. 2008), Dendrocincla Gray (Weir & Price 2011), Pteroglossus Illiger (Patel et al. 2011) and Pyrilia Bonaparte (Eberhard & Bermingham 2005), which occurred between 3 and 10 mya. Although these spatio-temporal patterns of diversification are more commonly found between Amazonian-Atlantic forest lineages, broader sampling in some lineages suggests a more complex evolutionary history in these regions, as illustrated by the case of the Xiphorhynchus guttatus (Lichtenstein)guttatoides (Lafresnaye)-sussurrans (Jardine) complex (Rocha et al. 2015), in which the Atlantic Forest lineages are closely related to the Guianan AOE populations and not to the southeastern Amazonian populations. ...
Megascops is the most species-rich owl genus in the New World, with 21 species currently recognized. Phylogenetic relationships within this genus are notoriously difficult to establish due to the considerable plumage similarity among species and polymorphism within species. Previous studies have suggested that the widespread lowland Amazonian M. watsonii might include more than one species, and that the Atlantic Forest endemic M. atricapilla is closely related to the M. watsonii complex, but these relationships are as yet poorly understood. A recently published phylogeny of Megascops demonstrated that M. watsonii is paraphyletic with respect to M. atricapilla and that genetic divergences among some populations of M. watsonii are equal to or surpass the degree of differentiation between some M. watsonii and M. atricapilla. To shed light on the taxonomic status of these species and populations within them, we conducted a multi-character study based on molecular, morphological, and vocal characters. We sequenced three mitochondrial (cytb, CO1 and ND2) and three nuclear genes (BF5, CHD and MUSK) for 49 specimens, covering most of the geographic ranges of M. watsonii and M. atricapilla, and used these sequences to estimate phylogenies under alternative Bayesian, Maximum Likelihood, and multilocus coalescent species tree approaches. We studied 252 specimens and vocal parameters from 83 recordings belonging to 65 individuals, distributed throughout the ranges of M. watsonii and M. atricapilla. We used Discriminant Function Analysis (DFA) to analyze both morphometric and vocal data, and a pairwise diagnostic test to evaluate the significance of vocal differences between distinct genetic lineages. Phylogenetic analyses consistently recovered six statistically well-supported clades whose relationships are not entirely in agreement with currently recognized species limits in M. watsonii and M. atricapilla. Morphometric analyses did not detect significant differences among clades. High plumage variation among individuals within clades was usually associated with the presence of two or more color morphs. By contrast, vocal analyses detected significant differentiation among some clades but considerable overlap among others, with some lineages (particularly the most widespread one) exhibiting significant regional variation. The combined results allow for a redefinition of species limits in both M. watsonii and M. atricapilla, with the recognition of four additional species, two of which we describe here as new. We estimated most cladogenesis in the Megascops atricapilla-M. watsonii complex as having taken place during the Plio-Pleistocene, with the development of the modern Amazonian and São Francisco drainages and the expansion and retraction of forest biomes during interglacial and glacial periods as likely events accounting for this relatively recent burst of diversification.
... Accordingly, taxa occupying the interfluvia separated by the largest Central Amazonian rivers (whether originating due to the river barrier or forest refuge hypotheses) come into contact in river headwaters or regions where the river has shifted course, resulting in introgressive hybridization in these places, creating a ring of interlinking taxa. Such patterns are noted in the examples of Pteroglossus Illiger, 1811 and Ramphastos Linnaeus, 1758 toucans (Eberhard & Bermingham, 2005;Patané et al., 2009), Pionopsitta Bonaparte, 1854 parrots (Eberhard & Bermingham, 2005), Xiphorhynchus woodcreepers (Aleixo, 2004;Pulido-Santacruz et al., 2018), wedgebilled woodcreeper Glyphorhynchus spirurus (Vieillot, 1819), scale-backed antbird Willisornis poecilinotus (Cabanis, 1847) (Weir et al., 2015;Pulido-Santacruz et al., 2018) and white-crowned manakin Dixiphia pipra (Linnaeus, 1758) (Castro-Astor, 2014). ...
... Accordingly, taxa occupying the interfluvia separated by the largest Central Amazonian rivers (whether originating due to the river barrier or forest refuge hypotheses) come into contact in river headwaters or regions where the river has shifted course, resulting in introgressive hybridization in these places, creating a ring of interlinking taxa. Such patterns are noted in the examples of Pteroglossus Illiger, 1811 and Ramphastos Linnaeus, 1758 toucans (Eberhard & Bermingham, 2005;Patané et al., 2009), Pionopsitta Bonaparte, 1854 parrots (Eberhard & Bermingham, 2005), Xiphorhynchus woodcreepers (Aleixo, 2004;Pulido-Santacruz et al., 2018), wedgebilled woodcreeper Glyphorhynchus spirurus (Vieillot, 1819), scale-backed antbird Willisornis poecilinotus (Cabanis, 1847) (Weir et al., 2015;Pulido-Santacruz et al., 2018) and white-crowned manakin Dixiphia pipra (Linnaeus, 1758) (Castro-Astor, 2014). ...
The black-throated trogon, Trogon rufus, is a widespread, polytypic species-complex with a convoluted taxonomic history. Here, we integrated morphological, vocal and genetic datasets, including spectral data and digital quantification of barred plumage, to assess and redefine its species limits according to the foremost species concepts. We suggest the recognition of four named and one new species. Trogon tenellus and T. cupreicauda are divergent across Central and South America without geographic overlap or intermediates. Trogon chrysochloros in the Atlantic Forests of Brazil is phenotypically, genetically and ecologically distinct. In Amazonia, Trogon rufus consists of three phenotypically distinct subspecies intergrading with each other in a ring-like formation around central Amazonian rivers. Trogon rufus rufus in the Guiana Shield, Trogon rufus amazonicus in southeastern Amazonia and Trogon rufus sulphureus in western Amazonia, with contact across the Lower Amazon and Madeira rivers, likely due to secondary contact between incompletely diverged lineages. The unique combination of song, morphology and mtDNA features of an unnamed, isolated population in the Atlantic Forest of northeastern Brazil resulted in its description as a new species, known only from the type locality and considered here as Critically Endangered, requiring urgent conservation actions.
... Although a considerable amount of Amazonian tree diversity seems to have originated in the Pleistocene (Richardson, Pennington, Pennington, & Hollingsworth, 2001), most plant species diversity in the Neotropics was also proven to be ancient, with great diversification more than 50 Mya (Wilf, 2003;Wing et al., 2009). Even birds, which were used as a model in the original refugia-hypothesis paper, began to diversify before the onset of the Pleistocene (Cheviron et al., 2005;Eberhard & Bermingham, 2005;Ribas, Gaban-Lima, Miyaki, & Cracraft, 2005). ...
The spatial distribution of biodiversity and related processes is the core of
Biogeography. Amazonia is the world's most diverse rainforest and the primary
source of diversity to several Neotropical regions. The origins of such diversity continue to be an unresolved question in evolutionary biology. Among many competing
hypotheses to explain the evolution of the Amazonian biodiversity, one stands out as
the most influential: the refugia hypothesis by Jürgen Haffer. Here, we provide a
chronological overview on how the refugia hypothesis evolved over the decades and
how the criticism from different fields affected its acceptance. We conclude that the
refugia hypothesis alone cannot explain the diversification of the complex Amazonian
diversity, and perhaps it was not the most important diversification mechanism.
However, the debate provoked by refugia has produced a great amount of knowledge
on Amazonian climatic, geological, and evolutionary processes, as well as on species
distributions, movements, and history.
... We therefore used a calibration for cytochrome b of 2.1% divergence per million years per position. This rate has been used in parrots (Groombridge et al. 2004;Eberhard & Bermingham 2005;Tavares et al. 2006;Ribas & Miyaki 2007;Ribas et al. 2009) and other birds (Shields & Wilson 1987;Tarr & Fleischer 1993;Fleischer et al. 1998;Weir & Schluter 2008). ...
The long-tailed parakeets of the genus Psittacula Cuvier, 1800 have thus far been regarded as a homogeneous and mono-phyletic group of parrots. We used nucleotide sequences of two genetic markers (mitochondrial CYTB, nuclear RAG-1) to reconstruct the phylogenetic relationships of Psittacula and closely related species. We found that the Asian genus Psit-tacula is apparently paraphyletic because two genera of short-tailed parrots, Psittinus Blyth, 1842 and Tanygnathus Wagler, 1832, cluster within Psittacula, as does †Mascarinus Lesson, 1830. To create monophyletic genera, we propose recognition of the following genera: Himalayapsitta Braun, 2016 for P. himalayana, P. finschii, P. roseata, and P. cyanocephala; Nicopsitta Braun, 2016 for P. columboides and P. calthrapae; Belocercus S. Müller, 1847 for P. longicauda; Psittacula Cuvier, 1800 for P. alexandri and P. derbiana; Palaeornis Vigors, 1825 for †P. wardi and P. eupatria; and Alexandrinus Braun, 2016 for P. krameri, †P. exsul, and P. (eques) echo. Additionally, Psittacula krameri and P. alexandri are paraphyletic species, which should be split to form monophyletic species.
... In this case, the description of the different subspecies based on the morphological variation found in different portions of the geographic ranges of both species would appear to be no more than a reflection of the phenotypic polymorphism found in these woodpeckers (West-Eberhard, 1989). Our findings are consistent with the perspective of Eberhard and Bermingham (2005), who argue that subspecies do not reflect any systematic pattern of genetic variation. One good example of this is the endangered subspecies Polioptila californica californica, which does not present any geographic structuring to support the validity of the taxon (Zink, Groth, Vázquez-Miranda, & Barrowclough, 2013). ...
We evaluated the relationship between Celeus undatus and Celeus grammicus, with the objective of clarifying their evolutionary history. We analysed fragments of the mitochondrial and nuclear genes of 57 specimens. For comparative purposes, we inspected the plumage patterns of 77 skins. Our findings highlight the absence of reciprocal monophyly between the two taxa, given their reduced genetic divergence, and the lack of any clear separation of the two forms in the haplotype networks. A similar situation was found in the STRUCTURE analysis, with reciprocal contributions from the two taxa to the respective clusters, indicating that C. grammicus and C. undatus cannot be differentiated using the molecular markers. Corroborating the genetic data, our plumage analyses also failed to find any clear diagnostic characters between the polytypic C. undatus and C. grammicus, as they are defined at present. The genetic profile is consistent with either extensive historical gene flow between the species or, alternatively, incomplete lineage sorting, rather than recent secondary contact. The lack of monophyly between the two taxa impeded subspecies‐level phylogeographic inferences, with the subspecific variation being interpreted as a probable artefact of the phenotypic plasticity of the two forms. These findings indicate clearly that the two taxa form a single evolutionary unit, in which the morphological differentiation used to diagnose the species, combined with their geographic distribution, is at odds with the incomplete separation of the taxa. This may reflect disparities in the rates of differentiation between molecular and phenotypic markers, which is possibly due to the variation in selection pressures along a humidity gradient in Amazonia.
