Evaluating Results

2021 ◽  
pp. 186-216
Author(s):  
Andrew V. Z. Brower ◽  
Randall T. Schuh

This chapter explores the tools used to evaluate the quality and plausibility of results of phylogenetic analyses. The term “fit” has been widely used in the phylogenetic literature to indicate the degree to which data conform to (or are explained by) a cladogram. The most commonly used measure of fit applied to discrete character data is the consistency index, or ci. Meanwhile, measures of synapomorphy are less frequently reported than the consistency index. The chapter then considers the resolution of branches; multiple equally parsimonious cladograms; successive approximations weighing; and data decisiveness. It also differentiates between total evidence and consensus, before describing supertrees. Finally, the chapter looks at approaches for evaluating support or stability of phylogenetic results, including branch support, jackknifing, bootstrapping, randomization tests, and sensitivity analysis.

1995 ◽  
Vol 347 (1320) ◽  
pp. 213-234 ◽  

Phylogenedc reladonships of higher taxa of echinoids have been invesdgated using a 163 character morphological data base and molecular sequences from large and small subunit (LSU and SSU) ribosomal RNA (rRNA) genes. The complete ssu rRNA gene has been sequenced for 21 taxa, with representatives from nine of the 14 extant orders of Echinoidea. Partial LSU sequences, representing the first 400 base pairs (b.p.) from the 5' end were also sequenced for three taxa to complement an existing data base of ten taxa. The two molecular sequences provided a total of 371 variable sites, of which 143 were phylogenetically informative (compared to 145 phylogenetically informative sites from morphological data). Morphological, LSU and SSU data have been analysed separately and together. Morphological and ssu sequence data generate topologies that are not significantly in conflict (under Templeton’s test), but the strong signal pairing arbaciids with clypeasteroids in the LSU derived tree marks the LSU sequence data as anomalous for this taxon. A ‘ total evidence’ approach derived a tree very similar in topology to that derived from morphological data. Rooted on the stem group echinoid Archaeocidaris , our total evidence tree suggested relationships of higher taxa as follows: Gidaroida Phormosomatidae Echinothuriidae Diadematidae Spatangoida Clypeasteroida, Cassiduloida Calycina, Arbacioida Stomopneustidae Glyphocidaridae Temnopleuridae Echinometridae Echinidae, Strongylocentridae. Phylogenetic analyses run both with and without key fossil taxa yielded slightly different topologies. It is important to include fossil taxa in a phylogenetic analysis where there are long stem-group branches or where the crown group is highly derived.


2002 ◽  
Vol 93 (4) ◽  
pp. 333-353 ◽  
Author(s):  
Julia J. Day

ABSTRACTThe Eocene sparid fauna (Teleostei: Percoidei) from Monte Bolca, Italy and from the London Clay, U.K. is revised based on re-examination of the type material and phylogenetic analyses of primarily osteological data. Two phylogenetic analyses, one of the Eocene taxa and a combined analysis of fossil and extant taxa, were performed. The addition of fossils to the extant data greatly increased numbers of most parsimonious trees, destabilising and obscuring basal relationships within the Sparidae. Combination of the data from fossil and extant data also affected relationships among the fossil taxa, changing some from those recovered using fossil data alone and destabilising others. Successive approximations character weighting supported the inclusion of the Eocene taxa within a monophyletic Sparidae. The genus Sparnodus, as previously conceived, is paraphyletic and is partitioned to remove the paraphyly. Five monotypic genera are recognised, including three new genera, Abromasta, Ellaserrata and Pseudosparnodus. Inclusion of the fossils in the phylogenetic analysis implies a minimum age of origin for the Sparidae of 55 Ma with most Recent sparid fauna in place no later than the Miocene, and provides further evidence that the diversification of feeding strategies occurred early on in the evolutionary history of the group.


2005 ◽  
Vol 79 (24) ◽  
pp. 15503-15510 ◽  
Author(s):  
Apurva Narechania ◽  
Zigui Chen ◽  
Rob DeSalle ◽  
Robert D. Burk

ABSTRACT The human papillomaviruses (HPVs) have long been thought to follow a monophyletic pattern of evolution with little if any evidence for recombination between genomes. On the basis of this model, both oncogenicity and tissue tropism appear to have evolved once. Still, no systematic statistical analyses have shown whether monophyly is the rule across all HPV open reading frames (ORFs). We conducted a taxonomic analysis of 59 mucosal/genital HPVs using whole-genome and sliding-window similarity measures; maximum-parsimony, neighbor-joining, and Bayesian phylogenetic analyses; and localized incongruence length difference (LILD) analyses. The algorithm for the LILD analyses localized incongruence by calculating the tree length differences between constrained and unconstrained nodes in a total-evidence tree across all HPV ORFs. The process allows statistical evaluation of every ORF/node pair in the total-evidence tree. The most significant incongruence was observed at the putative high-risk (i.e., cancer-associated) node, the common oncogenic ancestor for alpha HPV species 9 (e.g., HPV type 16 [HPV16]), 11, 7 (e.g., HPV18), 5, and 6. Although these groups share early-gene homology, including high degrees of similarity among E6 and E7, groups 9 and 11 diverge from groups 7, 5, and 6 with respect to L2 and L1. The HPV species groups primarily associated with cervical and anogenital cancers appear to follow two distinct evolutionary paths, one conferred by the early genes and another by the late genes. The incongruence in the genital HPV phylogeny could have occurred from an early recombination event, an ecological niche change, and/or asymmetric genome convergence driven by intense selection. These data indicate that the phylogeny of the oncogenic HPVs is complex and that their evolution may not be monophyletic across all genes.


2017 ◽  
Vol 31 (3) ◽  
pp. 317 ◽  
Author(s):  
Jesús A. Cruz-López ◽  
Oscar F. Francke

Systematic relationships among Laniatores have received considerable attention during the past few years. Many significant taxonomic changes have been proposed, particularly in the superfamily Gonyleptoidea. As part of this superfamily, the basalmost Stygnopsidae is the least known family. In order to propose the first total evidence phylogeny of the family, we produced four datasets: three molecular markers – partial nuclear 28S, mitochondrial ribosomal 16S, mitochondrial protein-encoding cytochrome c oxidase subunit I; and 72 morphological characters. With these data, we performed three different phylogenetic analyses: (1) Bayesian Inference with molecular data, and (2) Bayesian Inference and (3) Maximum Likelihood using combined data. Our results are congruent: a monophyletic Stygnopsidae subdivided into two major clades: Stygnopsinae and Karosinae, subfam. nov. The following genera are redefined: Stygnopsis, Hoplobunus and Serrobunus stat. rev. The following taxa are described: Iztlina venefica, gen. nov., sp. nov. and Tonalteca, gen. nov. Additionally, the following changes are proposed: Serrobunus queretarius (Šilhavý, 1974), comb. nov., Stygnopsis apoalensis (Goodnight & Goodnight, 1973), comb. nov., Stygnopsis mexicana (Roewer, 1915), comb. nov., Stygnopsis oaxacensis (Goodnight & Goodnight, 1973), comb. nov., and Tonalteca spinooculorum (Goodnight & Goodnight, 1973), comb. nov. We also discuss the status of the genera Isaeus stat. rev. and Mexotroglinus. Finally, we discuss the evolution of male genitalia and convergence of selected homoplastic diagnostic characters.


Phytotaxa ◽  
2020 ◽  
Vol 442 (2) ◽  
pp. 61-79 ◽  
Author(s):  
DENIS DAVYDOV ◽  
SERGEI SHALYGIN ◽  
ANNA VILNET

A cyanobacterial strain isolated from the Svalbard archipelago was studied using morphological, ecological, and molecular approaches. The morphology of natural populations fit well the description of the Leptolyngbya s.l. however, in culture, they formed specific nodules that prevented affiliation to this genus. Further phylogenetic analyses including the 16S rRNA gene and 16S-23S ITS region revealed that the strain corresponds to the genus Nodosilinea. Based on this total evidence approach, we provide here a description of the new taxon Nodosilinea svalbardensis sp. nov.


2006 ◽  
Vol 84 (3) ◽  
pp. 501-507
Author(s):  
Ying Chang ◽  
Chan Woon Khiong ◽  
Sean W. Graham ◽  
Benito C. Tan

The systematic position of Pterogonidium pulchellum (W.J. Hooker) Muell. Hal. in the Sematophyllaceae and Piloecium pseudorufescens (Hampe) Muell. Hal. in the Myuriaceae is reexamined with new evidence derived from rbcL gene sequences. A total of 18 taxa from Sematophyllaceae, Hypnaceae, Myuriaceae, and Hookeriaceae were included, 11 of which were newly sequenced for the rbcL gene. Analyses were done using maximum parsimony, maximum likelihood (TrN + Γ + I model and GTR + Γ + I model), and Bayesian inference (GTR + Γ + I model). The results show that Pterogonidium pulchellum has a closer relationship with members of Hypnaceae than with Sematophyllaceae, while Piloecium pseudorufescens forms a clade with the Sematophyllaceae in all phylogenetic analyses, with robust branch support. Two SOWH tests were carried out and the results show that it is not appropriate to classify Pterogonidium pulchellum in Sematophyllaceae and it is also not appropriate to classify Piloecium pseudorufescens in Myuriaceae.


2016 ◽  
Vol 12 (5) ◽  
pp. 20151003 ◽  
Author(s):  
Thomas Guillerme ◽  
Natalie Cooper

Analyses of living and fossil taxa are crucial for understanding biodiversity through time. The total evidence method allows living and fossil taxa to be combined in phylogenies, using molecular data for living taxa and morphological data for living and fossil taxa. With this method, substantial overlap of coded anatomical characters among living and fossil taxa is vital for accurately inferring topology. However, although molecular data for living species are widely available, scientists generating morphological data mainly focus on fossils. Therefore, there are fewer coded anatomical characters in living taxa, even in well-studied groups such as mammals. We investigated the number of coded anatomical characters available in phylogenetic matrices for living mammals and how these were phylogenetically distributed across orders. Eleven of 28 mammalian orders have less than 25% species with available characters; this has implications for the accurate placement of fossils, although the issue is less pronounced at higher taxonomic levels. In most orders, species with available characters are randomly distributed across the phylogeny, which may reduce the impact of the problem. We suggest that increased morphological data collection efforts for living taxa are needed to produce accurate total evidence phylogenies.


Botany ◽  
2016 ◽  
Vol 94 (9) ◽  
pp. 863-884 ◽  
Author(s):  
David S. Gernandt ◽  
Garth Holman ◽  
Christopher Campbell ◽  
Matthew Parks ◽  
Sarah Mathews ◽  
...  

Relationships of living and fossil Pinaceae were inferred using parsimony and Bayesian inference of morphological characters and plastid and nuclear DNA sequences. When considering extant taxa only, adding molecular to morphological characters resulted in markedly increased resolution and branch support compared with analysis of morphology alone. Including 45 fossil taxa resulted in drastically decreased resolution in morphology-based consensus trees. We evaluated the effect on branch support and resolution of including DNA sequences, deleting fossils lacking information for cone scale apices and seeds, using reduced consensus methods, and using implied weighting, and found that the greatest improvements were found by including DNA sequences and using implied weighting. The tree topologies from parsimony and Bayesian inference confirm previous findings that the fossil genus Pseudoaraucaria and a few species of Pityostrobus from the Lower Cretaceous are related to abietoid genera, and that other species of Pityostrobus are pinoid and closely related to Pinus. Focusing phylogenetic analyses on the most complete fossil cones, specifically those that are anatomically preserved and include both cone scale apices and seeds, and taking into account homoplasy, resulted in the clearest hypotheses for the timing and sequence of diversification in the family.


2021 ◽  
Author(s):  
Brendon E Boudinot ◽  
Marek L Borowiec ◽  
Matthew M Prebus

Within the Formicidae, the higher classification of nearly all subfamilies has been recently revised due to the findings of molecular phylogenetics. Here, we integrate morphology and molecular data to holistically address the evolution and classification of the ant genus Lasius, its tribe Lasiini, and their subfamily Formicinae. We accomplish this through a critical re-examination of morphology of extant and fossil taxa, molecular phylogenetic analyses, total-evidence dating under fossilized birth-death process, phylogeography, and ancestral state estimation. We use these results to provide revised taxonomic definitions for the Lasiini and select genera, and we provide a key to the genera of the Lasiini with emphasis on the Lasius genus group. We find that the crown Lasiini originated around the end of the Cretaceous on the Eurasian continent and is divisible into four morphologically distinct clades: Cladomyrma, the Lasius genus group, the Prenolepis genus group, and a previously undetected lineage we name XXXgen. n. The crown of the Lasius genus group is considerably younger than that of the Prenolepis genus group, indicating that extinction has played a major role in the evolution of the former clade. Lasius itself is divided into two well-supported monophyletic groups which are approximately equally speciose. We present evidence that temporary social parasitism and fungiculture arose in Lasius two times independently. Additionally, we recover the paraphyly of three Lasius subgenera and propose replacing all subgenera with an informal species group classification: Lasius = Acanthomyopssyn. rev., = Austrolasiussyn. n., = Cautolasiussyn. n., = Chthonolasius vsyn. n., = Dendrolasiussyn. n. Total-evidence analysis reveals that the Baltic-region amber fossil species Lasius pumilus and Pseudolasius boreus are misplaced to genus; we therefore designate XXXgen. n. for the former and XXXgen. n. for the latter. Further, we transfer XXX and Glaphyromyrmex out of the tribe, considering the former to be incertae sedis in the subfamily, and the latter a member of the Formicini (tribal transfer). Two final taxonomic actions are deemed necessary: synonymy of Lasius escamole Reza, 1925 with Liometopum apiculatum Mayr, 1870 syn. n. (subfamilial transfer), and transfer of Paratrechina kohli to Anoplolepis (tribal transfer, forming A. kohli (Forel, 1916) n. comb.).


PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1805 ◽  
Author(s):  
J. Antonio Baeza

Porcelain crabs from the closely related generaPetrolisthes,Liopetrolisthes, andAllopetrolisthesare known for their diversity of lifestyles, habitats, and coloration. The evolutionary relationships among the species belonging to these three genera is not fully resolved. A molecular phylogeny of the group may help to resolve the long-standing taxonomic question about the validity of the generaAllopetrolisthesandLiopetrolisthes. Using both ‘total evidence’ and single-marker analyses based on a 362-bp alignment of the 16S rRNA mitochondrial DNA and a 328-bp alignment of the Histone 3 nuclear DNA, the phylogenetic relationships among 11 species fromPetrolisthes(6 species),Liopetrolisthes(2 species), andAllopetrolisthes(3 species), all native to the south eastern Pacific, were examined. The analyses supported three pairs of sister species:L. mitra+L. patagonicus,P. tuberculatus+P. tuberculosus, andA. angulosus+A. punctatus. No complete segregation of species, according to genera, was evident from tree topologies. Bayesian-factor analyses revealed strong support for the unconstrained tree instead of an alternative tree in which monophyly of the three genera was forced. Thus, the present molecular phylogeny does not support the separation of the species within this complex into the generaPetrolisthes,Liopetrolisthes, andAllopetrolisthes. Taking into account the above and other recent molecular phylogenetic analyses focused on other representatives from the family Porcellanidae, it is tentatively proposed to eliminate the generaLiopetrolisthesandAllopetrolisthes, and to transfer their members to the genusPetrolisthes.


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