The reconstructed cranium of Pierolapithecus and the evolution of the great ape face.

Pierolapithecus catalaunicus (~12 million years ago, northeastern Spain) is key to understanding the mosaic nature of hominid (great ape and human) evolution. Notably, its skeleton indicates that an orthograde (upright) body plan preceded suspensory adaptations in hominid evolution. However, there is ongoing debate about this species, partly because the sole known cranium, preserving a nearly complete face, suffers from taphonomic damage. We 1) carried out a micro computerized tomography (CT) based virtual reconstruction of the Pierolapithecus cranium, 2) assessed its morphological affinities using a series of two-dimensional (2D) and three-dimensional (3D) morphometric analyses, and 3) modeled the evolution of key aspects of ape face form. The reconstruction clarifies many aspects of the facial morphology of Pierolapithecus. Our results indicate that it is most similar to great apes (fossil and extant) in overall face shape and size and is morphologically distinct from other Middle Miocene apes. Crown great apes can be distinguished from other taxa in several facial metrics (e.g., low midfacial prognathism, relatively tall faces) and only some of these features are found in Pierolapithecus, which is most consistent with a stem (basal) hominid position. The inferred morphology at all ancestral nodes within the hominoid (ape and human) tree is closer to great apes than to hylobatids (gibbons and siamangs), which are convergent with other smaller anthropoids. Our analyses support a hominid ancestor that was distinct from all extant and fossil hominids in overall facial shape and shared many features with Pierolapithecus. This reconstructed ancestral morphotype represents a testable hypothesis that can be reevaluated as new fossils are discovered.

Parsimony analysis of phylogenomic datasets (I): scripts and guidelines for using TNT (Tree Analysis using New Technology).

We discuss here the use of TNT (Tree Analysis using New Technology) for phylogenomic analysis. For such data, parsimony is a useful alternative to model-based analyses, which frequently utilize models that make unrealistic assumptions (e.g. low heterotachy), struggle with high levels of missing data, etc. Parsimony and model-based methods often yield trees with few topological differences, which can then be analyzed further in order to investigate whether these few topological differences are due to undesirable analysis artefacts. This is facilitated by the greater speed and computational efficiency of parsimony, which allow for a more in-depth analysis of datasets. We here briefly describe the computationally most efficient and versatile parsimony software, TNT, which can be used for phylogenetic and phylogenomic analyses. In particular, we describe and provide a series of scripts that are specifically designed for the analysis of phylogenomic datasets. This includes scripts for concatenation of gene data files in different formats, generation of plots and datasets with different levels of gene/taxon occupancy, calculation of different support measures and phylogenetic reconstruction based on concatenated matrices and single genes. The execution of the scripts is also demonstrated with video clips (https://www.youtube.com/channel/UCpIgK8sVH-yK0Bo3fK62IxA). Lastly, we describe the main commands and functions that enable efficient phylogenomic analyses in TNT.

Parsimony analysis of phylogenomic datasets (II): evaluation of PAUP*, MEGA and MPBoot.

This paper examines the implementation of parsimony methods in the programs PAUP*, MEGA and MPBoot, and compares them with TNT. PAUP* implements standard, well-tested algorithms, and flexible search strategies and options for handling trees; its main drawback is the lack of advanced search algorithms, which makes it difficult to find most parsimonious trees for large and complex datasets. In addition, branch-swapping can be much slower than in TNT for datasets with large numbers of taxa, although this is only occasionally a problem for phylogenomic datasets given that they typically have small numbers of taxa. The parsimony implementation of MEGA has major drawbacks. MEGA often fails to find parsimonious trees because it does not perform all possible branch swapping subtree pruning regrafting (SPR)/tree bisection-reconnection (TBR) rearrangements. It furthermore fails to properly handle ambiguity or multiple equally parsimonious trees, and it uses the same addition sequence for all bootstrap replicates. The latter yields values of group support that depend on the order in which taxa are listed in the dataset. In addition, tree searches are very slow and do not facilitate the exploration of different starting points (as random seed is fixed). MPBoot searches for optimal trees using the ratchet, but it is based on SPR instead of TBR (and only evaluates by default a subset of the SPR rearrangements). MPBoot approximates bootstrap frequencies by first finding a sample of trees and then selecting from those trees for every replicate, without performing a tree-search. The approximation is too rough in many cases, producing serious under- or overestimations of the correct support values and, for most kinds of datasets, slower estimations than can be obtained with TNT. In addition, bootstrapping with PAUP*, MEGA or MPBoot can attribute strong supports to groups that have no support at all under any meaningful concept of support, such as likelihood ratios or Bremer supports. In TNT, this problem is decreased by using the strict consensus tree to represent each replicate, or eliminated entirely by using different approximations of the Bremer support.

Disintegration of the genus Prosopis L. (Leguminosae, Caesalpinioideae, mimosoid clade).

Robust evidence from phylogenomic analyses of 997 nuclear genes has recently shown, beyond doubt, that the genus Prosopis is polyphyletic with three separate lineages, each with affinities to other genera of mimosoids: (i) Prosopisafricana is an isolated lineage placed in the grade of Plathymenia, Newtonia and Fillaeopsis that subtends the core mimosoid clade; (ii) the remaining Old World species of Prosopis form a clade that is sister to the Indo-Nepalese monospecific genus Indopiptadenia and (iii) New World Prosopis has the Namibian / Namaqualand monospecific endemic genus Xerocladia nested within it. This means that it is now clear that maintaining the unity of the genus Prosopis sensu Burkart (1976) is no longer tenable. These three distinct lineages of Prosopis species correspond directly to Burkart's (1976) sectional classification of the genus, to previously recognised genera and to the differences in types of armature that underpin Burkart's sections. Here, we address this non-monophyly by resurrecting three segregate genera - Anonychium, Neltuma and Strombocarpa and provide 57 new name combinations where necessary, while maintaining the morphologically distinctive and geographically isolated genera Xerocladia and Indopiptadenia. The genus Prosopis itself is reduced to just three species and an emended description is presented. The impacts of these name changes for a genus of such high ecological and human use importance are discussed. These impacts are mitigated by clear differences in armature which facilitate identification and by potential benefits from the deeper biological understanding brought about by recognition of these divergent lineages at generic rank. We provide an identification key to genera and present a map showing the distributions of the segregate genera, as well as drawings and photos illustrating variation in armature and fruits.

Assessing topological congruence among concatenation-based phylogenomic approaches in empirical datasets.

Assessing the effect of methodological decisions on the resulting hypotheses is critical in phylogenetics. Recent studies have focused on evaluating how model selection, orthology definition and confounding factors affect phylogenomic results. Here, we compare the results of three concatenated phylogenetic methods (Maximum Likelihood, ML; Bayesian Inference, BI; Maximum Parsimony, MP) in 157 empirical phylogenomic datasets. The resulting trees were very similar, with 96.7% of all nodes shared between BI and ML (90.6% for ML-MP and 89.1% for BI-MP). Differing nodes were predominantly those of lower support. The main conclusions of most of the studies agreed for the three phylogenetic methods and the discordance involved nodes considered as recalcitrant problems in systematics. The differences between methods were proportionally larger in datasets that analyze the relationships at higher taxonomic levels (particularly phyla and kingdoms), and independent of the number of characters included in the datasets. Note: a spanish version of this article is available in the Supplementary material (Supplementary material online).

PASOS: a method for the phylogenetic analysis of shape ontogenies.

We present a novel phylogenetic approach to infer ancestral ontogenies of shape characters described as landmark configurations. The method is rooted in previously published theoretical developments to analyse landmark data in a phylogenetic context with parsimony as the optimality criterion, in this case using the minimization of differences in landmark position to define not only ancestral shapes but also the changes in developmental timing between ancestor-descendant shape ontogenies. Evolutionary changes along the tree represent changes in relative developmental timing between ontogenetic trajectories (possible heterochronic events) and changes in shape within each stage. The method requires the user to determine the shape of the specimens between two standard events, for instance birth and onset of sexual maturity. Once the ontogenetic trajectory is discretized into a series of consecutive stages, the method enables the user to identify changes in developmental timing associated with changes in the offset and/or onset of the shape ontogenetic trajectories. The method is implemented in a C language program called SPASOS. The analysis of two empirical examples (anurans and felids) using this novel method yielded results in agreement with previous hypotheses about shape evolution in these groups based on non-phylogenetic analyses.

Agathis trees of Patagonia's Cretaceous-Paleogene death landscapes and their evolutionary significance.

PREMISE OF THE STUDY: The fossil record of Agathis historically has been restricted to Australasia. Recently described fossils from the Eocene of Patagonian Argentina showed a broader distribution than found previously, which is reinforced here with a new early Paleocene Agathis species from Patagonia. No previous phylogenetic analyses have included fossil Agathis species. METHODS: We describe macrofossils from Patagonia of Agathis vegetative and reproductive organs from the early Danian, as well as leaves with Agathis affinities from the latest Maastrichtian. A total evidence phylogenetic analysis is performed, including the new Danian species together with other fossil species having agathioid affinities. KEY RESULTS: Early Danian Agathis immortalis sp. nov. is the oldest definite occurrence of Agathis and one of the most complete Agathis species in the fossil record. Leafy twigs, leaves, pollen cones, pollen, ovuliferous complexes, and seeds show features that are extremely similar to the living genus. Dilwynites pollen grains, associated today with both Wollemia and Agathis and known since the Turonian, were found in situ within the pollen cones. CONCLUSIONS: Agathis was present in Patagonia ca. 2 million years after the K-Pg boundary, and the putative latest Cretaceous fossils suggest that the genus survived the K-Pg extinction. Agathis immortalis sp nov. is recovered in a stem position for the genus, while A. zamunerae (Eocene, Patagonia) is recovered as part of the crown. A Mesozoic divergence for the Araucariaceae crown group, previously challenged by molecular divergence estimates, is supported by the combined phylogenetic analyses including the fossil taxa.

Combined phylogenetic analysis of the subclass Marchantiidae (Marchantiophyta): towards a robustly diagnosed classification.

The most extensive combined phylogenetic analyses of the subclass Marchantiidae yet undertaken was conducted on the basis of morphological and molecular data. The morphological data comprised 126 characters and 56 species. Taxonomic sampling included 35 ingroup species with all genera and orders of Marchantiidae sampled, and 21 outgroup species with two genera of Blasiidae (Marchantiopsida), 15 species of Jungermanniopsida (the three subclasses represented) and the three genera of Haplomitriopsida. Takakia ceratophylla (Bryophyta) was employed to root the trees. Character sampling involved 92 gametophytic and 34 sporophytic traits, supplemented with ten continuous characters. Molecular data included 11 molecular markers: one nuclear ribosomal (26S), three mitochondrial genes (nad1, nad5, rps3) and seven chloroplast regions (atpB, psbT-psbH, rbcL, ITS, rpoC1, rps4, psbA). Searches were performed under extended implied weighting, weighting the character blocks against the average homoplasy. Clade stability was assessed across three additional weighting schemes (implied weighting corrected for missing entries, standard implied weighting and equal weighting) in three datasets (molecular, morphological and combined). The contribution from different biological phases regarding node recovery and diagnosis was evaluated. Our results agree with many of the previous studies but cast doubt on some relationships, mainly at the family and interfamily level. The combined analyses underlined the fact that, by combining data, taxonomic enhancements could be achieved regarding taxon delimitation and quality of diagnosis. Support values for many clades of previous molecular studies were improved by the addition of morphological data. The long-held assumption that morphology may render spurious or low-quality results in this taxonomic group is challenged. The morphological trends previously proposed are re-evaluated in light of the new phylogenetic scheme.

TNT version 1.5, including a full implementation of phylogenetic morphometrics.

Version 1.5 of the computer program TNT completely integrates landmark data into phylogenetic analysis. Landmark data consist of coordinates (in two or three dimensions) for the terminal taxa; TNT reconstructs shapes for the internal nodes such that the difference between ancestor and descendant shapes for all tree branches sums up to a minimum; this sum is used as tree score. Landmark data can be analysed alone or in combination with standard characters; all the applicable commands and options in TNT can be used transparently after reading a landmark data set. The program continues implementing all the types of analyses in former versions, including discrete and continuous characters (which can now be read at any scale, and automatically rescaled by TNT). Using algorithms described in this paper, searches for landmark data can be made tens to hundreds of times faster than it was possible before (from T to 3T times faster, where T is the number of taxa), thus making phylogenetic analysis of landmarks feasible even on standard personal computers.

The more, the better: the use of multiple landmark configurations to solve the phylogenetic relationships in musteloids.

Although the use of landmark data to study shape changes along a phylogenetic tree has become a common practice in evolutionary studies, the role of this sort of data for the inference of phylogenetic relationships remains under debate. Theoretical issues aside, the very existence of historical information in landmark data has been challenged, since phylogenetic analyses have often shown little congruence with alternative sources of evidence. However, most analyses conducted in the past were based upon a single landmark configuration, leaving it unsettled whether the incorporation of multiple configurations may improve the rather poor performance of this data source in most previous phylogenetic analyses. In the present study, we present a phylogenetic analysis of landmark data that combines information derived from several skeletal structures to derive a phylogenetic tree for musteloids. The analysis includes nine configurations representing different skeletal structures for 24 species. The resulting tree presents several notable concordances with phylogenetic hypotheses derived from molecular data. In particular, Mephitidae, Procyonidae, and Lutrinae plus the genera Martes, Mustela, Galictis, and Procyon were retrieved as monophyletic. In addition, other groupings were in agreement with molecular phylogenies or presented only minor discordances. Complementary analyses have also indicated that the results improve substantially when an increasing number of landmark configurations are included in the analysis. The results presented here thus highlight the importance of combining information from multiple structures to derive phylogenetic hypotheses from landmark data.

First phylogenetic analysis of the tribe Phyllotini (Rodentia: Sigmodontinae) combining morphological and molecular data.

Previous phylogenetic analyses of the tribe Phyllotini, one of the largest components of the subfamily Sigmodontinae, have been based on a single source of evidence. In particular, morphological analyses were largely based on craniodental data, almost neglecting the potential phylogenetic information present in the postcranium. Despite the significant advances made in relation to the knowledge of phyllotine phylogeny in recent times, there are several unsolved issues that highlight the importance of a phylogenetic analysis that integrates multiple sources of evidence, including previously considered sources as well as new sources of data. We present here the first combined phylogenetic analysis (morphological and molecular) of phyllotines, which includes the widest taxon and character sampling to date. Our dataset includes 164 morphological characters, of which 83 are postcranial characters, plus 3561 molecular characters, scored for 52 species from 34 genera of Oryzomyalia. In this study 75 postcranial characters not previously considered in this group are thoroughly described, and their utility for solving the relationships within Phyllotini is evaluated by means of different complementary analyses. Phyllotini was retrieved as a monophyletic clade in the combined analysis, with a composition that matches that obtained in most other recent analyses. All genera of phyllotines were monophyletic and show high support values. Abrotrichini, Akodontini and Oryzomyini were also monophyletic. The inclusion of postcranial data appears to be of limited utility to solve the phylogenetic relationships within Phyllotini.

Heavy metal resistant strains are widespread along Streptomyces phylogeny.

The genus Streptomyces comprises a group of bacteria species with high economic importance. Several of these species are employed at industrial scale for the production of useful compounds. Other characteristic found in different strains within this genus is their capability to tolerate high level of substances toxic for humans, heavy metals among them. Although several studies have been conducted in different species of the genus in order to disentangle the mechanisms associated to heavy metal resistance, little is known about how they have evolved along Streptomyces phylogeny. In this study we built the largest Streptomyces phylogeny generated up to date comprising six genes, 113 species of Streptomyces and 27 outgroups. The parsimony-based phylogenetic analysis indicated that (i) Streptomyces is monophyletic and (ii) it appears as sister clade of a group formed by Kitasatospora and Streptacidiphilus species, both genera also monophyletic. Streptomyces strains resistant to heavy metals are not confined to a single lineage but widespread along Streptomyces phylogeny. Our result in combination with genomic, physiological and biochemical data suggest that the resistance to heavy metals originated several times and by different mechanisms in Streptomyces history.

GB-to-TNT: facilitating creation of matrices from GenBank and diagnosis of results in TNT.

This paper presents a pipeline, implemented in an open-source program called GB→TNT (GenBank-to-TNT), for creating large molecular matrices, starting from GenBank files and finishing with TNT matrices which incorporate taxonomic information in the terminal names. GB→TNT is designed to retrieve a defined genomic region from a bulk of sequences included in a GenBank file. The user defines the genomic region to be retrieved and several filters (genome, length of the sequence, taxonomic group, etc.); each genomic region represents a different data block in the final TNT matrix. GB→TNT first generates Fasta files from the input GenBank files, then creates an alignment for each of those (by calling an alignment program), and finally merges all the aligned files into a single TNT matrix. The new version of TNT can make use of the taxonomic information contained in the terminal names, allowing easy diagnosis of results, evaluation of fit between the trees and the taxonomy, and automatic labelling or colouring of tree branches with the taxonomic groups they represent. © The Willi Hennig Society 2012.

Phylogenetic morphometrics (II): algorithms for landmark optimization.

This paper describes algorithms for optimizing two- or three-dimensional landmark data onto trees directly. The method is based on a first approximation using grids, and subsequent iterative refinement of the initial point estimates. Details of the implementation are discussed, as well as an empirical example. © The Willi Hennig Society 2010.

Phylogenetic morphometrics (I): the use of landmark data in a phylogenetic framework.

A method for the direct use of aligned landmark data (2D or 3D coordinates of comparable points) in phylogenetic analysis is described. The approach is based on finding, for each of the landmark points, the ancestral positions that minimize the distance between the ancestor/descendant points along the tree. Doing so amounts to maximizing the degree to which similar positions of the landmarks in different taxa can be accounted for by common ancestry, i.e. parsimony. This method requires no transformation of the aligned data or the results: the data themselves are the x, y, z coordinates of the landmarks, and the output of mapping a character onto a given tree is the x, y, z coordinates for the hypothetical ancestors. In the special case of collinear points, the results are identical to those of optimization of (continuous) additive characters.

Phylogenetic analysis of 73 060 taxa corroborates major eukaryotic groups.

Obtaining a well supported schema of phylogenetic relationships among the major groups of living organisms requires considering as much taxonomic diversity as possible, but the computational cost of calculating large phylogenies has so far been a major obstacle. We show here that the parsimony algorithms implemented in TNT can successfully process the largest phylogenetic data set ever analysed, consisting of molecular sequences and morphology for 73 060 eukaryotic taxa. The trees resulting from molecules alone display a high degree of congruence with the major taxonomic groups, with a small proportion of misplaced species; the combined data set retrieves these groups with even higher congruence. This shows that tree-calculation algorithms effectively retrieve phylogenetic history for very large data sets, and at the same time provides strong corroboration for the major eukaryotic lineages long recognized by taxonomists.