In this study, we present a detailed family-level phylogenetic hypothesis for the largest avian order (Aves: Passeriformes) and an unmatched multi-calibrated, relaxed clock inference for the diversification of crown passerines. Extended taxon sampling allowed the recovery of many challenging clades and elucidated their position in the tree. Acanthisittia appear to have diverged from all other passerines at the early Paleogene, which is considerably later than previously suggested. Thus, Passeriformes may be younger and represent an even more intense adaptive radiation compared to the remaining avian orders. Based on our divergence time estimates, a novel hypothesis for the diversification of modern Suboscines is proposed. According to this hypothesis, the first split between New and Old World lineages would be related to the severing of the Africa-South America biotic connection during the mid-late Eocene, implying an African origin for modern Eurylaimides. The monophyletic status of groups not recovered by any subsequent study since their circumscription, viz. Sylvioidea including Paridae, Remizidae, Hyliotidae, and Stenostiridae; and Muscicapoidea including the waxwing assemblage (Bombycilloidea) were notable topological findings. We also propose possible ecological interactions that may have shaped the distinct Oscine distribution patterns in the New World. The insectivorous endemic Oscines of the Americas, Vireonidae (Corvoidea), Mimidae, and Troglodytidae (Muscicapoidea), probably interfered with autochthonous Suboscines through direct competition. Thus, the Early Miocene arrival of these lineages before any other Oscines may have occupied the few available niches left by Tyrannides, constraining the diversification of insectivorous Oscines that arrived in the Americas later. The predominantly frugivorous-nectarivorous members of Passeroidea, which account for most of the diversity of New World-endemic Oscines, may not have been subjected to competition with Tyrannides. In fact, the vast availability of frugivory niches combined with weak competition with the autochthonous passerine fauna may have been crucial for passeroids to thrive in the New World.

Most phylogenetic tree-generating programs produce a fully dichotomous phylogenetic tree. However, as different markers may produce distinct topologies for the same set of organisms, topological tests are used to estimate the statistical reliability of the clades. In this protocol, we provide step-by-step instructions on how to perform the widely used bootstrap test using MEGA. However, a single unstable lineage, also known as a rogue lineage, may decrease the bootstrap proportions in many branches of the tree. This occurs because rogue taxa tend to bounce between clades from one pseudo-replicate to the next, lowering bootstrap proportions for many correct clades. Thus, it is important to identify and exclude rogue taxa before initiating a final phylogenetic analysis; here, we provide this protocol using the RogueNaRok platform.

The Eurylaimides is one of the few passerine groups with a pantropical distribution. In this study, we generated a multi-calibrated tree with 83% of eurylaimid species diversity based on 30 molecular loci. Particular attention was given to the monotypic Sapayoidae to reconstruct the biogeography of this radiation. We conducted several topological tests including nonoverlapping subsampling of the concatenated alignment and coalescent species tree reconstruction. These tests firmly placed the South American Sapayoidae as the sister group to all other Eurylaimides families (split at ∼28 Ma), with increasing branch support as highly variable sites were removed. This topology is consistent with the breakup of the insular connection between Africa and South America (Atlantogea) that took place between the middle Eocene and the early Oligocene. We recovered Africa as the cradle of the core Eurylaimides, and this result is supported by all African lineages corresponding to the oldest splits within each family in this group. Our timescale suggests that desertification and the uplift of the Tibetan Plateau caused a parallel divergence between African and Asian lineages in all major clades in the core Eurylaimides at 22-9 Ma. We also propose that the ground-foraging behavior in the Pittidae ancestor allowed the pitta lineage to thrive and coexist with the older arboreal lineages of the core Eurylaimides. In contrast, the diversification of pittas in Australia was likely hindered by direct competition with the endemic ground-foraging oscines that had been well established in that continent since the Eocene.

Phylogenetics has a central role in the biological sciences. We suggest a hands-on exercise to demonstrate the task of character coding and its importance in phylogenetic systematics. This exercise is appropriate for undergraduate students in life sciences and related courses. The teacher must provide a single group of masks in which color patterns, textures, and formats provide the characters to fill the data matrix. (The masks could be replaced by a set of other complex objects.) In this case, because there is no actual phylogeny, students will not be concerned with recovering the correct topology. Character coding is the aim of the exercise. After the character matrix is completed, a phylogenetic tree is drawn and the students interpret the evolution of a single character, starting from the common ancestor, based on the topological pattern of the tree and on the data matrix. In sequence, the students name and provide a full diagnosis for the group of masks as revealed by the topological pattern. The comparison between group results is also educational: there will be some common patterns between trees, but others will differ as in biological systematics.

Aim: Explanations of pantropical distributions are challenging for taxa that diverged during the Cenozoic, after Gondwana broke apart. The 'boreotropics hypothesis' suggests that pantropical birds originated in the Laurasian forests. Extant parrots (Psittaciformes) are one the most species-rich pantropical avian clades, but their known evolutionary history does not fit a boreotropical origin. Most living parrots and the earliest diverging lineages of the Psittaciformes inhabit the remnants of Gondwana, whereas the oldest stem and crown fossils are from the remnants of Laurasia. Our study proposes a biogeographic hypothesis that focuses on the Cenozoic connections between Laurasia and Gondwana to explain extant and fossil geographical distributions. Location: Global.Taxon: Psittaciformes. Methods:We generated a time tree using previously derived data from 32 molecular markers for 312 parrot species and reconstructed their biogeographic history using maximum likelihood. Two scenarios were compared: one with dispersal constrained to adjacent areas, including the connections between the Northern and Southern Hemispheres, and one without this constraint. Results:Our results indicate that the pantropical distribution of parrots was shaped by two major geological events. First, the final breakup of parts of Gondwana may have caused the first splits within crown parrots, establishing two parallel radiations: Psittacidae in the Neotropics and Psittaculidae in Australasia. Second, igneous palaeoprovinces could have connected major biogeographic realms. It seems that Atlantogea and Eurogondwana were important, as they connected South America, Africa and Europe, thus reconciling the Gondwanan crown splits and the early Laurasian fossils.Main Conclusions: Our time tree allowed more concise biogeographic correlations between parrots and their sister group, the passerines and Earth's tectonic history.The crown lineages of Psittacopasseres appear to have originated in the Southern Hemisphere remnants of Gondwana, but stem lineages appear to have been able to disperse into the Northern Hemisphere through palaeobiogeographic provinces in the Cenozoic.

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