scholarly journals Assessment of cladistic data availability for living mammals

2015 ◽  
Author(s):  
Thomas Guillerme ◽  
Natalie Cooper

Analyses of living and fossil taxa are crucial for understanding changes in biodiversity through time. The Total Evidence method allows living and fossil taxa to be combined in phylogenies, by using molecular data for living taxa and morphological data for both living and fossil taxa. With this method, substantial overlap of morphological data among living and fossil taxa is crucial for accurately inferring topology. However, although molecular data for living species is widely available, scientists using and generating morphological data mainly focus on fossils. Therefore, there is a gap in our knowledge of neontological morphological data even in well-studied groups such as mammals. We investigated the amount of morphological (cladistic) data available for living mammals and how this data was phylogenetically distributed across orders. 22 of 28 mammalian orders have < 25% species with available morphological data; this has implications for the accurate placement of fossil taxa, although the issue is less pronounced at higher taxonomic levels. In most orders, species with available data 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.

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.


2020 ◽  
Vol 34 (2) ◽  
pp. 113 ◽  
Author(s):  
Rafael Robles ◽  
Peter C. Dworschak ◽  
Darryl L. Felder ◽  
Gary C. B. Poore ◽  
Fernando L. Mantelatto

The axiidean families Callianassidae and Ctenochelidae, sometimes treated together as Callianassoidea, are shown to represent a monophyletic taxon. It comprises 265 accepted species in 74 genera, twice this number of species if fossil taxa are included. The higher taxonomy of the group has proved difficult and fluid. In a molecular phylogenetic approach, we inferred evolutionary relationships from a maximum-likelihood (ML) and Bayesian analysis of four genes, mitochondrial 16S rRNA and 12S rRNA along with nuclear histone H3 and 18S rRNA. Our sample consisted of 298 specimens representing 123 species plus two species each of Axiidae and Callianideidae serving as outgroups. This number represented about half of all known species, but included 26 species undescribed or not confidently identified, 9% of all known. In a parallel morphological approach, the published descriptions of all species were examined and detailed observations made on about two-thirds of the known fauna in museum collections. A DELTA (Description Language for Taxonomy), database of 135 characters was made for 195 putative species, 18 of which were undescribed. A PAUP analysis found small clades coincident with the terminal clades found in the molecular treatment. Bayesian analysis of a total-evidence dataset combined elements of both molecular and morphological analyses. Clades were interpreted as seven families and 53 genera. Seventeen new genera are required to reflect the molecular and morphological phylograms. Relationships between the families and genera inferred from the two analyses differed between the two strategies in spite of retrospective searches for morphological features supporting intermediate clades. The family Ctenochelidae was recovered in both analyses but the monophyly of Paragourretia was not supported by molecular data. The hitherto well recognised family Eucalliacidae was found to be polyphyletic in the molecular analysis, but the family and its genera were well defined by morphological synapomorphies. The phylogram for Callianassidae suggested the isolation of several species from the genera to which they had traditionally been assigned and necessitated 12 new generic names. The same was true for Callichiridae, with stronger ML than Bayesian support, and five new genera are proposed. Morphological data did not reliably reflect generic relationships inferred from the molecular analysis though they did diagnose terminal taxa treated as genera. We conclude that discrepancies between molecular and morphological analyses are due at least in part to missing sequences for key species, but no less to our inability to recognise unambiguously informative morphological synapomorphies. The ML analysis revealed the presence of at least 10 complexes wherein 2–4 cryptic species masquerade under single species names.


2020 ◽  
Author(s):  
Zachary H. Griebenow

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.


2021 ◽  
Author(s):  
E. J. Thompson ◽  
Melodina Fabillo

The taxonomy of Neurachninane has been unstable, with its member genera consisting of Ancistrachne, Calyptochloa, Cleistochloa, Dimorphochloa, Neurachne, Paraneurachne and Thyridolepis, changing since its original circumscription that comprised only the latter three genera. Recent studies on the phylogeny of Neurachninae have focused primarily on molecular data. We analysed the phylogeny of Neurachninae on the basis of molecular data from seven molecular loci (plastid markers: matK, ndhF, rbcL, rpl16, rpoC2 and trnLF, and ribosomal internal transcribed spacer, ITS) and morphological data from 104 morphological characters, including new taxonomically informative micromorphology of upper paleas. We devised an impact assessment scoring (IAS) protocol to aid selection of a tree for inferring the phylogeny of Neurachninae. Combining morphological and molecular data resulted in a well resolved phylogeny with the highest IAS value. Our findings support reinstatement of subtribe Neurachninae in its original sense, Neurachne muelleri and Dimorphochloa rigida. We show that Ancistrachne, Cleistochloa and Dimorphochloa are not monophyletic and Ancistrachne maidenii, Calyptochloa, Cleistochloa and Dimorphochloa form a new group, the cleistogamy group, united by having unique morphology associated with reproductive dimorphism.


2020 ◽  
Author(s):  
Tamara Spasojevic ◽  
Gavin R Broad ◽  
Ilari E Sääksjärvi ◽  
Martin Schwarz ◽  
Masato Ito ◽  
...  

Abstract Taxon sampling is a central aspect of phylogenetic study design, but it has received limited attention in the context of total-evidence dating, a widely used dating approach that directly integrates molecular and morphological information from extant and fossil taxa. We here assess the impact of commonly employed outgroup sampling schemes and missing morphological data in extant taxa on age estimates in a total-evidence dating analysis under the uniform tree prior. Our study group is Pimpliformes, a highly diverse, rapidly radiating group of parasitoid wasps of the family Ichneumonidae. We analyze a data set comprising 201 extant and 79 fossil taxa, including the oldest fossils of the family from the Early Cretaceous and the first unequivocal representatives of extant subfamilies from the mid Paleogene. Based on newly compiled molecular data from ten nuclear genes and a morphological matrix that includes 222 characters, we show that age estimates become both older and less precise with the inclusion of more distant and more poorly sampled outgroups. These outgroups not only lack morphological and temporal information, but also sit on long terminal branches and considerably increase the evolutionary rate heterogeneity. In addition, we discover an artefact that might be detrimental for total-evidence dating: “bare-branch attraction”, namely high attachment probabilities of certain fossils to terminal branches for which morphological data are missing. Using computer simulations, we confirm the generality of this phenomenon and show that a large phylogenetic distance to any of the extant taxa, rather than just older age, increases the risk of a fossil being misplaced due to bare-branch attraction. After restricting outgroup sampling and adding morphological data for the previously attracting, bare branches, we recover a Jurassic origin for Pimpliformes and Ichneumonidae. This first age estimate for the group not only suggests an older origin than previously thought, but also that diversification of the crown group happened well before the Cretaceous-Paleogene boundary. Our case study demonstrates that in order to obtain robust age estimates, total-evidence dating studies need to be based on a thorough and balanced sampling of both extant and fossil taxa, with the aim of minimizing evolutionary rate heterogeneity and missing morphological information.


2005 ◽  
Vol 272 (1572) ◽  
pp. 1577-1586 ◽  
Author(s):  
Niklas Wahlberg ◽  
Michael F Braby ◽  
Andrew V.Z Brower ◽  
Rienk de Jong ◽  
Ming-Min Lee ◽  
...  

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.


2021 ◽  
Author(s):  
Zachary H. Griebenow

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 &amp; 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 synonymised 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.


2020 ◽  
Author(s):  
Johannes S Neumann ◽  
Rob Desalle ◽  
Apurva Narechania ◽  
Bernd Schierwater ◽  
Michael Tessler

Abstract There are considerable phylogenetic incongruencies between morphological and phylogenomic data for the deep evolution of animals. This has contributed to a heated debate over the earliest-branching lineage of the animal kingdom: the sister to all other Metazoa (SOM). Here, we use published phylogenomic data sets ($\sim $45,000–400,000 characters in size with $\sim $15–100 taxa) that focus on early metazoan phylogeny to evaluate the impact of incorporating morphological data sets ($\sim $15–275 characters). We additionally use small exemplar data sets to quantify how increased taxon sampling can help stabilize phylogenetic inferences. We apply a plethora of common methods, that is, likelihood models and their “equivalent” under parsimony: character weighting schemes. Our results are at odds with the typical view of phylogenomics, that is, that genomic-scale data sets will swamp out inferences from morphological data. Instead, weighting morphological data 2–10$\times $ in both likelihood and parsimony can in some cases “flip” which phylum is inferred to be the SOM. This typically results in the molecular hypothesis of Ctenophora as the SOM flipping to Porifera (or occasionally Placozoa). However, greater taxon sampling improves phylogenetic stability, with some of the larger molecular data sets ($&gt;$200,000 characters and up to $\sim $100 taxa) showing node stability even with $\geqq100\times $ upweighting of morphological data. Accordingly, our analyses have three strong messages. 1) The assumption that genomic data will automatically “swamp out” morphological data is not always true for the SOM question. Morphological data have a strong influence in our analyses of combined data sets, even when outnumbered thousands of times by molecular data. Morphology therefore should not be counted out a priori. 2) We here quantify for the first time how the stability of the SOM node improves for several genomic data sets when the taxon sampling is increased. 3) The patterns of “flipping points” (i.e., the weighting of morphological data it takes to change the inferred SOM) carry information about the phylogenetic stability of matrices. The weighting space is an innovative way to assess comparability of data sets that could be developed into a new sensitivity analysis tool. [Metazoa; Morphology; Phylogenomics; Weighting.]


2019 ◽  
Author(s):  
Cara Van Der Wal ◽  
Shane T. Ahyong ◽  
Simon Y. W. Ho ◽  
Luana S. F. Lins ◽  
Nathan Lo

The mantis shrimp superfamily Squilloidea, with over 185 described species, is the largest superfamily in the crustacean order Stomatopoda. To date, phylogenetic relationships within this superfamily have been comprehensively analysed using morphological data, with six major generic groupings being recovered. Here, we infer the phylogeny of Squilloidea using a combined dataset comprising 75 somatic morphological characters and four molecular markers. Nodal support is low when the morphological and molecular datasets are analysed separately but improves substantially when combined in a total-evidence phylogenetic analysis. We obtain a well resolved and strongly supported phylogeny that is largely congruent with previous estimates except that the Anchisquilloides-group, rather than the Meiosquilla-group, is the earliest-branching lineage in Squilloidea. The splits among the Anchisquilloides- and Meiosquilla-groups are followed by those of the Clorida-, Harpiosquilla-, Squilla- and Oratosquilla-groups. Most of the generic groups are recovered as monophyletic, with the exception of the Squilla- and Oratosquilla-groups. However, many genera within the Oratosquilla-group are not recovered as monophyletic. Further exploration with more extensive molecular sampling will be needed to resolve relationships within the Oratosquilla-group and to investigate the adaptive radiation of squilloids. Overall, our results demonstrate the merit of combining morphological and molecular datasets for resolving phylogenetic relationships.


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