scholarly journals A Simulation-Based Evaluation of Total-Evidence Dating Under the Fossilized Birth-Death Process

2018 ◽  
Author(s):  
Arong Luo ◽  
David A. Duchêne ◽  
Chi Zhang ◽  
Chao-Dong Zhu ◽  
Simon Y.W. Ho
Keyword(s):  
Morphological Characters ◽  
Nucleotide Sequences ◽  
Tree Topology ◽  
Molecular Dating ◽  
Total Evidence ◽  
Morphological Data ◽  
Death Process ◽  
Nucleotide Sequence Data ◽  
Wide Range ◽  
Birth Death

AbstractBayesian molecular dating is widely used to study evolutionary timescales. This procedure usually involves phylogenetic analysis of nucleotide sequence data, with fossil-based calibrations applied as age constraints on internal nodes of the tree. An alternative approach is Bayesian total-evidence dating, which involves the joint analysis of molecular data from present-day taxa and morphological data from both extant and fossil taxa. Part of its appeal stems from the fossilized birth-death process, which provides a model of lineage diversification for the prior on the tree topology and node times. However, total-evidence dating faces a number of considerable challenges, especially those associated with fossil sampling and evolutionary models for morphological characters. We conducted a simulation study to evaluate the performance of total-evidence dating with the fossilized birth-death model. We simulated fossil occurrences and the evolution of nucleotide sequences and morphological characters under a wide range of conditions. Our analyses show that fossil occurrences have a greater influence than the degree of among-lineage rate variation or the number of morphological characters on estimates of node times and the tree topology. Total-evidence dating generally performs well in recovering the relationships among extant taxa, but has difficulties in correctly placing fossil taxa in the tree and identifying the number of sampled ancestors. The method yields accurate estimates of the origin time of the fossilized birth-death process and the ages of the root and crown group, although the precision of these estimates varies with the probability of fossil occurrence. The exclusion of morphological characters results in a slight overestimation of node times, whereas the exclusion of nucleotide sequences has a negative impact on inference of the tree topology. Overall, our results provide a detailed view of the performance of total-evidence dating, which will inform further development of the method and its application to key questions in evolutionary biology.

scholarly journals A Simulation-Based Evaluation of Tip-Dating Under the Fossilized Birth–Death Process

2019 ◽  
Vol 69 (2) ◽  
pp. 325-344 ◽  
Author(s):  
Arong Luo ◽  
David A Duchêne ◽  
Chi Zhang ◽  
Chao-Dong Zhu ◽  
Simon Y W Ho
Keyword(s):  
Morphological Characters ◽  
Nucleotide Sequences ◽  
Tree Topology ◽  
Molecular Dating ◽  
Morphological Data ◽  
Death Process ◽  
Joint Analysis ◽  
Nucleotide Sequence Data ◽  
Wide Range ◽  
Birth Death

Abstract Bayesian molecular dating is widely used to study evolutionary timescales. This procedure usually involves phylogenetic analysis of nucleotide sequence data, with fossil-based calibrations applied as age constraints on internal nodes of the tree. An alternative approach is tip-dating, which explicitly includes fossil data in the analysis. This can be done, for example, through the joint analysis of molecular data from present-day taxa and morphological data from both extant and fossil taxa. In the context of tip-dating, an important development has been the fossilized birth–death process, which allows non-contemporaneous tips and sampled ancestors while providing a model of lineage diversification for the prior on the tree topology and internal node times. However, tip-dating with fossils faces a number of considerable challenges, especially, those associated with fossil sampling and evolutionary models for morphological characters. We conducted a simulation study to evaluate the performance of tip-dating using the fossilized birth–death model. We simulated fossil occurrences and the evolution of nucleotide sequences and morphological characters under a wide range of conditions. Our analyses of these data show that the number and the maximum age of fossil occurrences have a greater influence than the degree of among-lineage rate variation or the number of morphological characters on estimates of node times and the tree topology. Tip-dating with the fossilized birth–death model generally performs well in recovering the relationships among extant taxa but has difficulties in correctly placing fossil taxa in the tree and identifying the number of sampled ancestors. The method yields accurate estimates of the ages of the root and crown group, although the precision of these estimates varies with the probability of fossil occurrence. The exclusion of morphological characters results in a slight overestimation of node times, whereas the exclusion of nucleotide sequences has a negative impact on inference of the tree topology. Our results provide an overview of the performance of tip-dating using the fossilized birth–death model, which will inform further development of the method and its application to key questions in evolutionary biology.

scholarly journals A skyline birth-death process for inferring the population size from a reconstructed tree with occurrences

2020 ◽  
Author(s):  
Jérémy Andréoletti ◽  
Antoine Zwaans ◽  
Rachel C. M. Warnock ◽  
Gabriel Aguirre-Fernández ◽  
Joëlle Barido-Sottani ◽  
...  
Keyword(s):  
Population Size ◽  
Total Evidence ◽  
Morphological Data ◽  
Death Process ◽  
Model Parameters ◽  
Large Set ◽  
The Past ◽  
Population Sizes ◽  
Past Population ◽  
Birth Death

AbstractPhylodynamic models generally aim at jointly inferring phylogenetic relationships, model parameters, and more recently, population size through time for clades of interest, based on molecular sequence data. In the fields of epidemiology and macroevolution these models can be used to estimate, respectively, the past number of infected individuals (prevalence) or the past number of species (paleodiversity) through time. Recent years have seen the development of “total-evidence” analyses, which combine molecular and morphological data from extant and past sampled individuals in a unified Bayesian inference framework. Even sampled individuals characterized only by their sampling time, i.e. lacking morphological and molecular data, which we call occurrences, provide invaluable information to reconstruct past population sizes.Here, we present new methodological developments around the Fossilized Birth-Death Process enabling us to (i) efficiently incorporate occurrence data while remaining computationally tractable and scalable; (ii) consider piecewise-constant birth, death and sampling rates; and (iii) reconstruct past population sizes, with or without knowledge of the underlying tree. We implement our method in the RevBayes software environment, enabling its use along with a large set of models of molecular and morphological evolution, and validate the inference workflow using simulations under a wide range of conditions.We finally illustrate our new implementation using two empirical datasets stemming from the fields of epidemiology and macroevolution. In epidemiology, we apply our model to the Covid-19 outbreak on the Diamond Princess ship. We infer the total prevalence throughout the outbreak, by taking into account jointly the case count record (occurrences) along with viral sequences for a fraction of infected individuals. In macroevolution, we present an empirical case study of cetaceans. We infer the diversity trajectory using molecular and morphological data from extant taxa, morphological data from fossils, as well as numerous fossil occurrences. Our case studies highlight that the advances we present allow us to further bridge the gap between between epidemiology and pathogen genomics, as well as paleontology and molecular phylogenetics.

scholarly journals Impacts of Taxon-Sampling Schemes on Bayesian Molecular Dating under the Unresolved Fossilized Birth-Death Process

2021 ◽  
Author(s):  
Arong Luo ◽  
Chi Zhang ◽  
Qing-Song Zhou ◽  
Simon Y.W. Ho ◽  
Chao-Dong Zhu
Keyword(s):  
Molecular Dating ◽  
Total Evidence ◽  
Death Process ◽  
Taxon Sampling ◽  
Data Set ◽  
Sampling Density ◽  
Sampling Schemes ◽  
Divergence Time Estimates ◽  
Tree Topologies ◽  
Birth Death

Evolutionary timescales can be estimated using a combination of genetic data and fossil evidence based on the molecular clock. Bayesian phylogenetic methods such as tip dating and total-evidence dating provide a powerful framework for inferring evolutionary timescales, but the most widely used priors for tree topologies and node times often assume that present-day taxa have been sampled randomly or exhaustively. In practice, taxon sampling is often carried out so as to include representatives of major lineages, such as orders or families. We examined the impacts of these diversified sampling schemes on Bayesian molecular dating under the unresolved fossilized birth-death (FBD) process, in which fossil taxa are topologically constrained but their exact placements are not inferred. We used synthetic data generated by simulation of nucleotide sequence evolution, fossil occurrences, and diversified taxon sampling. Our analyses show that increasing sampling density does not substantially improve divergence-time estimates under benign conditions. However, when the tree topologies were fixed to those used for simulation or when evolutionary rates varied among lineages, the performance of Bayesian tip dating improves with sampling density. By exploring three situations of model mismatches, we find that including all relevant fossils without pruning off those inappropriate for the FBD process can lead to underestimation of divergence times. Our reanalysis of a eutherian mammal data set confirms some of the findings from our simulation study, and reveals the complexity of diversified taxon sampling in phylogenomic data sets. In highlighting the interplay of taxon-sampling density and other factors, the results of our study have useful implications for Bayesian molecular dating in the era of phylogenomics.

scholarly journals Towards a phylogeny of the Metazoa: evaluating alternative phylogenetic positions of Platyhelminthes, Nemertea, and Gnathostomulida, with a critical reappraisal of cladistic characters

2004 ◽  
Vol 73 (1-2) ◽  
pp. 3-163 ◽  
Author(s):  
Ronald A. Jenner
Keyword(s):  
Sister Group ◽  
Morphological Characters ◽  
Total Evidence ◽  
Morphological Data ◽  
Future Research ◽  
Sister Group Relationship ◽  
Cladistic Analyses ◽  
Phylogenetic Hypotheses ◽  
Data Matrices

This paper critically assesses all morphological cladistic analyses of the Metazoa that were published during the last one and a half decades. Molecular and total evidence analyses are also critically reviewed. This study focuses on evaluating alternative phylogenetic positions of the ‘acoelomate’ worms: Platyhelminthes, Nemertea, and Gnathostomulida. This paper consists of two parts. In Part I, all recently proposed sister group hypotheses and the supporting synapomorphies for these phyla are evaluated. Discrepancies in the treatment of corresponding characters in different cladistic analyses are identified, and where possible, resolved. In Part II, the overall phylogenetic significance across the Metazoa of all characters relevant for placing the ‘acoelomate’ worms is examined. The coding and scoring of these characters for other phyla are evaluated, and uncertainties in our understanding are pointed out in order to guide future research. The characters discussed in this paper are broadly categorized as follows: epidermis and cuticle, reproduction and sexual condition, development, larval forms, coeloms and mesoderm source, nervous system and sensory organs, nephridia, musculature, digestive system, and miscellaneous characters. Competing phylogenetic hypotheses are compared in terms of several criteria: 1) taxon sampling and the fulfillment of domain of definition for each character; 2) character sampling; 3) character coding; 4) character scoring and quality of primary homology; 5) quality of the proposed diagnostic synapomorphies as secondary homologies. On the basis of this study I conclude that a sister group for the Platyhelminthes has not yet been unambiguously established. A clade minimally composed of Neotrochozoa (Mollusca, Sipuncula, Echiura, Annelida) emerges as the most likely sister group of the Nemertea on the basis of morphological and total evidence analyses. Finally, morphological data currrently favor a sister group relationship of Gnathostomulida and Syndermata (probably plus Micrognathozoa). In contrast, molecular or total evidence analyses have not identified a reliable sister group of Gnathostomulida.Further progress in our understanding of metazoan phylogeny crucially depends on the improvement of the quality of currently adopted cladistic data matrices. A thorough reassessment of many of the more than 70 morphological characters discussed here is necessary. Despite the recent compilation of comprehensive data matrices, the power to test competing hypotheses of higher-level metazoan relationships is critically compromised due to uncritical data selection and poor character study in even the most recently published cladistic analyses.

A new skink of the genus Scincella Mittleman, 1950 (Squamata: Scincidae) from Ba Den Mountain, Tay Ninh Province, southern Vietnam

Zootaxa ◽  
2019 ◽  
Vol 4648 (2) ◽  
pp. 273-286
Author(s):  
SANG NGOC NGUYEN ◽  
VU DANG HOANG NGUYEN ◽  
LUAN THANH NGUYEN ◽  
ROBERT W. MURPHY
Keyword(s):  
New Species ◽  
Endemic Species ◽  
Morphological Characters ◽  
Nucleotide Sequences ◽  
Morphological Data ◽  
Medium Size ◽  
Southern Vietnam ◽  
Males And Females ◽  
Coi Sequences ◽  
Dorsal Pattern

Ba Den is an isolated mountain in southern Vietnam and home to two endemic species of lizards. Herein, we describe another endemic species, a new skink of the genus Scincella Mittleman, 1950, from the area based on morphological data, including hemipenial characters and nucleotide sequences of COI. The following morphological characters diagnose Scincella badenensis sp. nov.: medium size in adults (snout-vent length up to 64.4 mm); toes reach to fingers when limbs adpressed; midbody scale rows 32–36, smooth; paravertebral scales 67–71; dorsal scales not enlarged; ventral scale rows 68–74; supraoculars four; prefrontals in broad contact with one another; loreal scales two; tympanum deeply sunk, without auricular lobules; two enlarged anterior temporal scales; smooth lamellae beneath toe IV 18–20; pair of enlarged precloacal scales; hemipenes short, smooth and forked near the tip with two short lobes and two small terminal papillae; no dorsal pattern in males; and females with black interruptive vertebral line. The new species differs from its congeners by at least 10.4% uncorrected p-distance in COI sequences. 

Morphologic variation in the USDA/ARS rhubarb germplasm collection

2009 ◽  
Vol 8 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Alberto Pantoja ◽  
Joseph C. Kuhl
Keyword(s):  
Germplasm Collection ◽  
Morphological Characters ◽  
Morphological Data ◽  
Skin Colour ◽  
Base Thickness ◽  
Flesh Colour ◽  
Combining Data ◽  
Wide Range ◽  
Morphologic Variation ◽  
The Mean

Rhubarb includes approximately 60 species in the genusRheum. It has been utilized for thousands of years for medicinal purposes, but only recently identified for its culinary use. In the mid 1700s, edible petioles were discovered on seedlings from rhubarb species. Hundreds of cultivars have since been identified for a wide range of uses from tarts to wine. Unfortunately, propagation by seed and irregular naming has resulted in a plethora of similarly named cultivars and multitude of phenotypes. Fifteen morphological characters were evaluated to differentiate rhubarb cultivars in the USDA, ARSRheumcollection in Palmer, Alaska. Two years of morphological data, focusing on horticultural characteristics indicated variation between the years. To improve cultivar resolution, the results suggest using 1 year's data instead of combining data from different years. The mean °Brix observed was 3.8, with a range from 2.2 to 6.1. Flesh colour and basal skin colour were poorly correlated (R2 = 0.462); overall skin colour was more red at the base than in the middle of the petiole. Rhubarb character categories, in particular petiole number and petiole base thickness, need to be modified to better anticipate the range of expected values, and thereby contribute improved reproducibility and reliability to separate cultivars based on morphological characters.

scholarly journals Synonymization of the male-based ant genus Phaulomyrma (Hymenoptera, Formicidae) with Leptanilla based upon Bayesian total-evidence phylogenetic inference

2020 ◽  
Author(s):  
Zachary H. Griebenow
Keyword(s):  
Sequence Data ◽  
Phylogenetic Inference ◽  
Morphological Characters ◽  
Molecular Data ◽  
Total Evidence ◽  
Morphological Data ◽  
Systematic Revision ◽  
Dna Sequence Data ◽  
Evidence Framework ◽  
Nuclear Loci

Abstract.Although molecular data have proven indispensable in confidently resolving the phylogeny of many clades across the tree of life, these data may be inaccessible for certain taxa. The resolution of taxonomy in the ant subfamily Leptanillinae is made problematic by the absence of DNA sequence data for leptanilline taxa that are known only from male specimens, including the monotypic genus Phaulomyrma Wheeler & Wheeler. Focusing upon the considerable diversity of undescribed male leptanilline morphospecies, the phylogeny of 35 putative morphospecies sampled from across the Leptanillinae, plus an outgroup, is inferred from 11 nuclear loci and 41 discrete male morphological characters using a Bayesian total-evidence framework, with Phaulomyrma represented by morphological data only. Based upon the results of this analysis Phaulomyrma is synonymized with Leptanilla Emery, and male-based diagnoses for Leptanilla that are grounded in phylogeny are provided, under both broad and narrow circumscriptions of that genus. This demonstrates the potential utility of a total-evidence approach in inferring the phylogeny of rare extant taxa for which molecular data are unavailable and begins a long-overdue systematic revision of the Leptanillinae that is focused on male material.

scholarly journals Craniodental morphology and phylogeny of marsupials

2021 ◽  
Author(s):  
Robin M. D. Beck ◽  
Robert Voss ◽  
Sharon Jansa
Keyword(s):  
Phylogenetic Analysis ◽  
Dna Sequences ◽  
Morphological Characters ◽  
Molecular Data ◽  
Morphological Data ◽  
Future Research ◽  
Data Types ◽  
Wide Range ◽  
Morphological And Molecular Data ◽  
Dense Sampling

The current literature on marsupial phylogenetics includes numerous studies based on analyses of morphological data with relatively limited sampling of Recent and fossil taxa, and many studies based on analyses of molecular data that include a dense sampling of Recent taxa, but relatively few that combine both data types. Another dichotomy in the marsupial phylogenetic literature is between studies that focus on New World taxa, others that focus on Sahulian taxa. To date, there has been no attempt to assess the phylogenetic relationships of the global marsupial fauna, based on combined analyses of morphology and molecular sequences, for a dense sampling of Recent and fossil taxa. For this report, we compiled morphological and molecular data from an unprecedented number of Recent and fossil marsupials. Our morphological data consist of 180 craniodental characters that we scored for 97 species representing every currently recognized Recent genus, 42 additional ingroup (crown-clade marsupial) taxa represented by well-preserved fossils, and 5 outgroups (non-marsupial metatherians). Our molecular data comprise 24.5 kb of DNA sequences from whole-mitochondrial genomes and six nuclear loci (APOB, BRCA1, GHR, RAG1, RBP3 and VWF) for 97 marsupial terminals (the same Recent taxa scored for craniodental morphology) and several placental and monotreme outgroups. The results of separate and combined analyses of these data using a wide range of phylogenetic methods support many currently accepted hypotheses of ingroup (marsupial) relationships, but they also underscore the difficulty of placing fossils with key missing data (e.g., †Evolestes), and the unique difficulty of placing others that exhibit mosaics of plesiomorphic and autapomorphic traits (e.g., †Yalkaparidon). Unique contributions of our study are (1) critical discussions and illustrations of marsupial craniodental morphology, including descriptions and illustrations of some features never previously coded for phylogenetic analysis; (2) critical assessments of relative support for many suprageneric clades; (3) estimates of divergence times derived from tip-and-node dating based on uniquely taxon-dense analyses; and (4) a revised, higher-order classification of marsupials accompanied by lists of supporting craniodental synapomorphies. Far from the last word on these topics, this report lays the foundation for future research that may be enabled by the discovery of new fossil taxa, better-preserved material of previously described taxa, novel morphological characters, and improved methods of phylogenetic analysis.

Allozyme Evidence for the Phylogeny of Giant New Caledonian Geckos (Squamata: Diplodactylidae: Rhacodactylus), with Comments on the Status of R. leachianus henkeli

1997 ◽  
Vol 45 (3) ◽  
pp. 317 ◽  
Author(s):  
D. A. Good ◽  
A. M. Bauer ◽  
R. A. Sadlier
Keyword(s):  
Phylogenetic Analysis ◽  
Morphological Characters ◽  
Total Evidence ◽  
Morphological Data ◽  
Branching Pattern ◽  
Phenetic Analysis ◽  
Allozyme Data ◽  
The Status ◽  
Distance Data ◽  
Nei's Genetic Distance

The phylogenetic analysis of allozyme characters within the New Caledonian giant geckos, genus Rhacodactylus, yields a pattern of relationships that is largely congruent with that derived from morphological data. A ‘total evidence’ approach, incorporating 13 allozyme and 29 morphological characters, yields a single most-parsimonious tree with the pattern: R. auriculatus ((R. leachainus (R. ciliatus, R. chahoua)) (R. sarasinorum, R. trachyrhynchus)). A phenetic analysis based on Nei’s genetic distance data results in a similar branching pattern. The genus Pseudothecadactylus is tentatively regarded as valid because allozyme data conflict strongly with morphological data that suggest that these geckos evolved from within Rhacodactylus. Allozymes and available morphological data do not support the recognition of the recently described subspecies R. leachianus henkeli.

scholarly journals Synergistic effects of combining morphological and molecular data in resolving the phylogeny of butterflies and skippers

2005 ◽  
Vol 272 (1572) ◽  
pp. 1577-1586 ◽  
Author(s):  
Niklas Wahlberg ◽  
Michael F Braby ◽  
Andrew V.Z Brower ◽  
Rienk de Jong ◽  
Ming-Min Lee ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Synergistic Effects ◽  
Strong Support ◽  
Sister Group ◽  
Morphological Characters ◽  
Molecular Data ◽  
Total Evidence ◽  
Data Matrix ◽  
Morphological Data ◽  
Combined Analysis

Phylogenetic relationships among major clades of butterflies and skippers have long been controversial, with no general consensus even today. Such lack of resolution is a substantial impediment to using the otherwise well studied butterflies as a model group in biology. Here we report the results of a combined analysis of DNA sequences from three genes and a morphological data matrix for 57 taxa (3258 characters, 1290 parsimony informative) representing all major lineages from the three putative butterfly super-families (Hedyloidea, Hesperioidea and Papilionoidea), plus out-groups representing other ditrysian Lepidoptera families. Recently, the utility of morphological data as a source of phylogenetic evidence has been debated. We present the first well supported phylogenetic hypothesis for the butterflies and skippers based on a total-evidence analysis of both traditional morphological characters and new molecular characters from three gene regions ( COI , EF-1α and wingless ). All four data partitions show substantial hidden support for the deeper nodes, which emerges only in a combined analysis in which the addition of morphological data plays a crucial role. With the exception of Nymphalidae, the traditionally recognized families are found to be strongly supported monophyletic clades with the following relationships: (Hesperiidae+(Papilionidae+(Pieridae+(Nymphalidae+(Lycaenidae+Riodinidae))))). Nymphalidae is recovered as a monophyletic clade but this clade does not have strong support. Lycaenidae and Riodinidae are sister groups with strong support and we suggest that the latter be given family rank. The position of Pieridae as the sister taxon to nymphalids, lycaenids and riodinids is supported by morphology and the EF-1α data but conflicted by the COI and wingless data. Hedylidae are more likely to be related to butterflies and skippers than geometrid moths and appear to be the sister group to Papilionoidea+Hesperioidea.

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