Phylogenetic relationships of woodcreepers (Aves: Dendrocolaptinae) – incongruence between molecular and morphological data

The woodcreepers is a highly specialized lineage within the New World suboscine radiation. Most systematic studies of higher level relationships of this group rely on morphological characters, and few studies utilizing molecular data exist. In this paper, we present a molecular phylogeny of the major lineages of woodcreepers (Aves: Dendrocolaptinae), based on nucleotide sequence data from a nuclear non-coding gene region (myoglobin intron II) and a protein-coding mitochondrial gene (cytochrome b ). A good topological agreement between the individual gene trees suggests that the resulting phylogeny reflects the true evolutionary history of woodcreepers well. However, the DNA-based phylogeny conflicts with the results of a parsimony analysis of morphological characters. The topological differences mainly concern the basal branches of the trees. The morphological data places the genus Drymornis in a basal position (mainly supported by characters in the hindlimb), while our data suggests it to be derived among woodcreepers. Unlike most other woodcreepers, Drymornis is ground-adapted, as are the ovenbirds. The observed morphological similarities between Drymornis and the ovenbird outgroup may thus be explained with convergence or with reversal to an ancestral state. This observation raises the question of the use of characters associated with locomotion and feeding in phylogenetic reconstruction based on parsimony.     

Character evolution in Hydrozoa (phylum Cnidaria)

The diversity of hydrozoan life cycles, as manifested in the wide range of polyp, colony, and medusa morphologies, has been appreciated for centuries. Unraveling the complex history of characters involved in this diversity is critical for understanding the processes driving hydrozoan evolution. In this study, we use a phylogenetic approach to investigate the evolution of morphological characters in Hydrozoa. A molecular phylogeny is reconstructed using ribosomal DNA sequence data. Several characters involving polyp, colony, and medusa morphology are coded in the terminal taxa. These characters are mapped onto the phylogeny and then the ancestral character states are reconstructed. This study confirms the complex evolutionary history of hydrozoan morphological characters. Many of the characters involving polyp, colony, and medusa morphology appear as synapomorphies for major hydrozoan clades, yet homoplasy is commonplace.     

Head capsule characters in the Hymenoptera and their phylogenetic implications

The head capsule of a taxon sample of three outgroup and 86 ingroup taxa is examined for characters of possible phylogenetic significance within Hymenoptera. 21 morphological characters are illustrated and scored, and their character evolution explored by mapping them onto a phylogeny recently produced from a large morphological data set. Many of the characters are informative and display unambiguous changes. Most of the character support demonstrated is supportive at the superfamily or family level. In contrast, only few characters corroborate deeper nodes in the phylogeny of Hymenoptera.     

Phylogenetic analyses of marine sponges within the order Verongida: a comparison of morphological and molecular data

Abstract. Because the taxonomy of marine sponges is based primarily on morphological characters that can display a high degree of phenotypic plasticity, current classifications may not always reflect evolutionary relationships. To assess phylogenetic relationships among sponges in the order Verongida, we examined 11 verongid species, representing six genera and four families. We compared the utility of morphological and molecular data in verongid sponge systematics by comparing a phylogeny constructed from a morphological character matrix with a phylogeny based on nuclear ribosomal DNA sequences. The morphological phylogeny was not well resolved below the ordinal level, likely hindered by the paucity of characters available for analysis, and the potential plasticity of these characters. The molecular phylogeny was well resolved and robust from the ordinal to the species level. We also examined the morphology of spongin fibers to assess their reliability in verongid sponge taxonomy. Fiber diameter and pith content were highly variable within and among species. Despite this variability, spongin fiber comparisons were useful at lower taxonomic levels (i.e., among congeneric species); however, these characters are potentially homoplasic at higher taxonomic levels (i.e., between families). Our molecular data provide good support for the current classification of verongid sponges, but suggest a re-examination and potential reclassification of the genera Aiolochroia and Pseudoceratina . The placements of these genera highlight two current issues in morphology-based sponge taxonomy: intermediate character states and undetermined character polarity.     

Dissecting the ancient rapid radiation of microgastrine wasp genera using additional nuclear genes

Previous estimates of a generic level phylogeny for the ubiquitous parasitoid wasp subfamily Microgastrinae (Hymenoptera) have been problematic due to short internal branches deep in the phylogeny. These short branches might be attributed to a rapid radiation among the taxa, the use of genes that are unsuitable for the levels of divergence being examined, or insufficient quantity of data. We added over 1200 nucleotides from four nuclear genes to a dataset derived from three genes to produce a dataset of over 3000 nucleotides per taxon. While the number of well-supported short branches in the phylogeny increased, we still did not obtain strong bootstrap support for every node. Parametric and nonparametric bootstrap simulations projected that an enormous, and likely unobtainable, amount of data would be required to get bootstrap support greater than 50% for every node. However, a marked increase in the number of well-supported nodes was seen when we conducted a Bayesian analysis of a combined dataset generated from morphological characters added to the seven gene dataset. Our results suggest that, in some cases, combining morphological and genetic characters may be the most practical way to increase support for short branches deep in a phylogeny.     

Molecular insights into Cumacean family relationships (Crustacea, Cumacea)

Cumaceans are a diverse order of small, benthic marine crustaceans. Phylogenetic hypotheses for the eight currently recognized cumacean families have not been formally proposed. However, based on external morphological traits and Linnean classification, a few conflicting hypotheses of relatedness have been proposed. Family definitions rely on morphological characters that often overlap and diagnoses are based on a combination of non-unique characters. Morphological analysis does not provide a well-resolved phylogeny. In the present study, we use amino acid sequences from the mitochondrial cytochrome oxidase I gene to produce a molecular phylogenetic hypothesis for the families of Cumacea. Phylogenetic analyses at the amino acid level were performed under Bayesian, likelihood, and parsimony methods. Results strongly suggest that families lacking an articulated telson form a monophyletic group. This pleotelson clade, composed of the families Bodotriidae, Leuconidae, and Nannastacidae, is the most derived within the Cumacea. Within this group, the Bodotriidae resolve paraphyletically, with Leuconidae and Nannastacidae embedded within it. Comparison of the molecular phylogeny with that based on morphology suggests that many "diagnostic" characters are homoplasious.     

Evaluating the efficacy of continuous quantitative characters for reconstructing the phylogeny of a morphologically homogeneous spider taxon (Araneae, Mygalomorphae, Antrodiaetidae, Antrodiaetus)

The use of continuous quantitative characters for phylogenetic analyses has long been contentious in the systematics literature. Recent studies argue for and against their use, but there have been relatively few attempts to evaluate whether these characters provide an accurate estimate of phylogeny, despite the fact that a number of methods have been developed to analyze these types of data for phylogenetic inference. A tree topology will be produced for a given methodology and set of characters, but little can be concluded with regards to the accuracy of phylogenetic signal without an independent evaluation of those characters. We assess the performance of continuous quantitative characters for the mygalomorph spider genus Antrodiaetus, a group that is morphologically homogeneous and one for which few discrete (morphological) characters have been observed. Phylogenetic signal contained in continuous quantitative characters is compared to an independently derived phylogeny inferred on the basis of multiple nuclear and mitochondrial gene loci. Tree topology randomizations, regression techniques, and topological tests all demonstrate that continuous quantitative characters in Antrodiaetus conflict with the phylogenetic signal contained in the gene trees. Our results show that the use of continuous quantitative characters for phylogenetic reconstruction may be inappropriate for reconstructing Antrodiaetus phylogeny and indicate that due caution should be exercised before employing this character type in the absence of other independently derived sources of characters.     

Similarity

Recent debates concerning conflicting hypotheses of higher-level phylogeny such as the sister-group relationships of tetrapods, turtles, birds and snakes, serve as examples in the analysis of the nature of morphological evidence as it is currently used in phylogeny reconstruction. We note a recent shift of emphasis towards ever-larger data matrices, which may come at the cost of detailed character analysis and argumentation. Because the assessment of morphological characters necessarily entails a conceptual element of abstraction, there is also a threat that preconceived notions of phylogeny influence character analysis. Because the test of congruence does not address character analysis in itself, we argue that character hypotheses, i.e. primary conjectures of homology, need to be testable, and potentially refutable, in their own right. We demonstrate the use of classical criteria of homology (topological relations and/or connectivity, in conjunction with the subsidiary criteria of special similarity and intermediate forms) in the test, and refutation, of morphological characters. Rejection of the classical criteria of homology in the test of morphological character hypotheses requires the formulation of alternative methods of test and potential falsification of morphological characters that have so far not been proposed. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 75 , 59–82.     

Phylogeny and host-plant association in the leaf beetle genus Trirhabda LeConte (Coleoptera: Chrysomelidae)

The leaf beetle genus Trirhabda contains 26 described species from the United States and Canada, feeding on host plants from the families Asteraceae and Hydrophyllaceae. In this study, we present a phylogeny for the genus that was reconstructed from mitochondrial COI and 12S rRNA fragments, nuclear ITS2 rRNA, and morphological characters. Both parsimony and mixed-model Bayesian likelihood analyses were performed. Under both methods, the mitochondrial and nuclear partitions support the same backbone phylogeny, as do the combined data. The utility of the molecular data is contrasted with the low phylogenetic signal among morphological characters. The phylogeny was used to trace the evolution of the host-plant association in Trirhabda. The recovered phylogeny shows that although the host-plant association is phylogenetically conservative, Trirhabda experienced one shift to a distantly related host-plant family, 6 shifts between host-plant tribes, and 6 between genera within tribes. The phylogeny reveals that Trirhabda were plesiomorphically adapted to tolerate complex secondary compounds of its host plants and this adaptation is retained in Trirhabda species, as evidenced by multiple shifts from chemically simpler host plants back to the more complex host plants.     

Molecular evolution inferred from small subunit rRNA sequences: what does it tell us about phylogenetic relationships and taxonomy of the parabasalids?

The Parabasala are a primitive group of protists divided into two classes: the trichomonads and the hypermastigids. Until recently, phylogeny and taxonomy of parabasalids were mainly based on the comparative analysis of morphological characters primarily linked to the development of their cytoskeleton. Recent use of molecular markers, such as small subunit (SSU) rRNA has led to now insights into the systematics of the Parabasala and other groups of prolists. An updated phylogeny based on SSU rRNA is provided and compared to that inferred from ultrastructural data. The SSU rRNA phylogeny contradicts the dogma equating simple characters with pumitive characters. Hypermastigids, possessing a hyperdeveloped cytoskeleton, exhibit the most basal emergence in the parabasalid lineage. Other observations emerge from the SSU rRNA analysis, such as the secondary loss of some cytoskeleton structures in all representatives of the Monocercomonadidae, the existence of secondarily free living taxa (reversibility of parasitism) and the evidence against the co-evolution of the endobiotic parabasalids and their animal hosts. According to phylogenies based on SSU rRNA, all the trichomonad families are not monophyletic groups, putting into question the validity of current taxonomic assignments. The precise branching order of some taxa remains unclear, but this issue can possibly be addressed by the molecular analysis of additional parabasalids. The goal of such additional analyses would be to propose, in a near future, a revision of the taxonomy of this group of protists that takes into account both molecular and morphological data.     

Using 18S rDNA to resolve diaptomid copepod (Copepoda: Calanoida: Diaptomidae) phylogeny: an example with the North American genera

The phylogenetic relationships among the numerous genera of diaptomid copepods remain elusive due to difficulties in obtaining sufficient numbers of phylogenetically informative morphological characters for cladistic analysis. Molecular phylogenetic techniques offer high potential to resolve phylogenetic relationships in the absence of sufficient morphological characters because of the ease in which many characters can be unambiguously coded. I present the first molecular phylogeny for diaptomid copepod genera using 18S rDNA. Specifically, I test Light’s (1939) hypothesis regarding the interrelationships among the North American diaptomid genera. The 18S phylogeny is remarkably consistent with Light’s hypothesis. The endemic North American genera represent a monophyletic group exclusive of the non-endemic genera. Moreover, his hypothesized basal genus for the North America genera, Hesperodiaptomus, is the basal genus in this analysis. However, his Leptodiaptomus group is not reciprocally monophyletic with his Hesperodiaptomus group, but is rather a derived member of the latter group. Finally, the genus Mastigodiaptomus is found to be more closely allied with the non-endemic genera, as Light suggested. This phylogeny contributes heavily to the understanding of phylogenetic relationships among North American diaptomids and has large implications for the systematics of diaptomids in general. The use of 18S rDNA sequences in phylogenetic analyses of diaptomid copepods can be used to confirm the monophyly of recognized genera, the interrelationships among genera, and subsequent biogeographic interpretation of the family’s diversification. The use of molecular data, such as 18S rDNA sequences, to test phylogenetic hypotheses based on a very limited number of morphological characters will be a particularly useful approach to phylogenetic analysis in this system.     

Re-examination and phylogeny of the genus Chondrostoma based on mitochondrial and nuclear data and the definition of 5 new genera

Previous molecular phylogenetic studies of the genus Chondrostoma (Cyprinidae: Leuciscinae) were unable to resolve the relationship among its major species groups. In this paper we present a phylogeny for this genus, based on five mitochondrial genes and the nuclear gene beta-actin, comprising a total of 4068 bp. Bayesian inference using all gene fragments yielded a fully resolved phylogeny, compatible with topologies obtained from individual fragments using maximum parsimony and minimum evolution. Mapping of morphological characters critical to the rasping feeding mode of most Chondrostoma species indicates that they evolved several times, and questions the use of these characters in the traditional definition of the genus. Our findings led us to the definition of the following new genera: Achondrostoma, Iberochondrostoma, Pseudochondrostoma, Protochondrostoma and Parachondrostoma. Our data contradict the hypothesis of a rapid radiation during Lago Mare phase, suggested by previous studies.     

Histological data in a combined phylogenetic analysis of scleractinian reef corals

Scleractinian systematics have undergone rapid changes due to increased use of molecular phylogenetics and new perspectives on skeletal morphology from micromorphology and microstructure. Despite this increase in characters there are still unresolved clades in the phylogeny, indicating that more characters are needed. This study investigates a new source of morphological data within the soft tissue of Indo‐Pacific scleractinian corals. Features of tissue layers, especially cnidocytes, are described in hematoxylin and eosin stained thin sections. Based on this new histological data source, a combined analysis with mitochondrial DNA and skeletal data is performed using parsimony and Bayesian analysis. Parsimony analysis yields three most‐parsimonious trees similar to trees based on Bayesian analysis. Character maps are also produced that show origination of histomorphological traits at deep nodes within the phylogeny. In general, both analyses retain the previously designated families Lobophylliidae and Merulinidae, but some genera are found to be paraphyletic. Nonetheless, the combined analysis produces a highly resolved and well‐supported phylogeny, which could lead to more effective use of biological conservation metrics based on evolutionary distinctiveness. These results show for the first time that inclusion of histomorphological characters improves the resolution of phylogenetic analyses of reef corals. J. Morphol. 277:494–511, 2016. © 2016 Wiley Periodicals, Inc.     

How our view of animal phylogeny was reshaped by molecular approaches: lessons learned

In the late 1980s, researchers began applying molecular sequencing tools to questions of deep animal phylogeny. These advances in sequencing were accompanied with improvements in computation and phylogenetic methods, and served to significantly reshape our understanding of metazoan evolution. Prior to this time, researchers asserted phylogenetic hypotheses based on their experience with taxa and to some degree, their authority. Molecular phylogenetic tools provided discrete methods and objective characters for reconstructing phylogeny. Nonetheless, major changes to widely accepted views, such as animal phylogeny, take time to be accepted. Development and acceptance of our current understanding of animal evolution occurred in three main phases: initial hypotheses based on 18S data, confirmation with additional molecular markers, and continued refinement with phylogenomics. With the advent of ideas such as Lophotrochozoa and Ecdysozoa, flaws in the traditional view became apparent. We now understand that complex morphological and embryological features (e.g., segmentation, coelom formation, development of body cavities) are much more evolutionarily plastic than previously recognized. Here, I explore how the transition from the traditional to the modern phylogenetic understanding of animal phylogeny occurred and examine some implications of this change in understanding. As the field moves forward, the utility of morphological and embryological characters for reconstruction of deep animal phylogeny should be discouraged. Instead, these characters should be interpreted in the light of independent phylogeny.     

A web-database of mammalian morphology and a reanalysis of placental phylogeny

Background  

Recent publications concerning the interordinal phylogeny of placental mammals have converged on a common signal, consisting of four major radiations with some ambiguity regarding the placental root. The DNA data with which these relationships have been reconstructed are easily accessible from public databases; access to morphological characters is much more difficult. Here, I present a graphical web-database of morphological characters focusing on placental mammals, in tandem with a combined-data phylogenetic analysis of placental mammal phylogeny.     

Evaluating the monophyly and phylogenetic relationships of Brassolini genera (Lepidoptera, Nymphalidae)

Abstract.  This study uses 80 morphological characters and cladistic analysis to evaluate the monophyly and phylogenetic relationships of 18 genera that constitute the butterfly tribe Brassolini. Most characters derive from genitalia, confirming previous generic definitions based mainly on wing characters, and showing that 16 of 18 genera are monophyletic. Mimoblepia Casagrande, syn.n. was subsumed within Opoptera Aurivillius to address the paraphyly of the latter, but resolution of the status of Aponarope Casagrande requires further study. The results suggest that the Brassolini includes six suprageneric groups/clades. Although this study verifies some genus-level relationships put forward over 100 years ago, some new hypotheses of relationships are proposed. Tracing larval host plant use onto the Brassolini phylogeny indicates that species in this tribe retain the use of Arecaceae and Poaceae from their 'satyroid' ancestors.     

THE USEFULNESS OF BEHAVIOR FOR PHYLOGENY ESTIMATION: LEVELS OF HOMOPLASY IN BEHAVIORAL AND MORPHOLOGICAL CHARACTERS

It is widely believed that behavior is more evolutionarily labile and/or more difficult to characterize than morphology, and thus that behavioral characters are not as useful as morphological characters for estimating phylogenetic relationships. To examine the relative utility of behavior and morphology for estimating phylogeny, we compared levels of homoplasy for morphological and behavioral characters that have been used in systematic studies. In an analysis of 22 data sets that contained both morphological and behavioral characters we found no significant difference between mean consistency indices (CIs, which measure homoplasy) within data sets for the two types of characters. In a second analysis we compared overall CIs for 8 data sets comprised entirely of behavioral characters with overall CIs for 32 morphological data sets and found no significant difference between the two types of data sets. For both analyses, 95% confidence limits on the difference between the two types of characters indicate that, even if given the benefit of the doubt, morphological characters could not have substantially higher mean CIs than behavioral characters. These results do not support the idea that behavioral characters are less useful than morphological characters for the estimation of phylogeny.     

A new phylogeny of swiftlets (Aves: Apodidae) based on cytochrome-b DNA

Due to a lack of distinctive morphological characters, swift taxonomy and phylogeny has always been an area of disagreement. To shed more light on this subject, we reconstructed swift(let) phylogeny based on 1143 bp of mitochondrial cytochrome-b DNA sequence. Although this is not the first attempt to reconstruct swift phylogeny using molecular data, our results show higher support for many of the branches due to our much longer sequences. However, placement of Hydrochous is still unexpected. Implementation of more conservative genetic regions and sampling of more taxa could solve this problem. Most importantly, the Collocaliini resolve as a monophyletic group. The internal structure of the group shows that non-echolocating Collocalia and echolocating Aerodramus form two distinct clades. This is in congruence with earlier classifications based on morphological characters, but in contrast with more recent classifications.