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Metrics details. The latest advancements in DNA sequencing technologies have facilitated the resolution of the phylogeny of insects, yet parts of the tree of Holometabola remain unresolved. The phylogeny of Neuropterida has been extensively studied, but no strong consensus exists concerning the phylogenetic relationships within the order Neuroptera. Here, we assembled a novel transcriptomic dataset to address previously unresolved issues in the phylogeny of Neuropterida and to infer divergence times within the group. We tested the robustness of our phylogenetic estimates by comparing summary coalescent and concatenation-based phylogenetic approaches and by employing different quartet-based measures of phylogenomic incongruence, combined with data permutations. Coniopterygidae is inferred as sister to all remaining neuropteran families suggesting that larval cryptonephry could be a ground plan feature of Neuroptera. A clade that includes Nevrorthidae, Osmylidae, and Sisyridae i.

A dialect map of the Indo-European languages. Reproduced with permission from Anttilap. The first two are structured entirely by binary splits; in the third there is almost no such branching, and the relationships between the subgroups take the form of a network of cross-cutting relationships instead.

Most importantly, the difference is by no means merely one of representation, but has implications for our understanding of the relationships between the early Indo-European languages and the real-world context in which they arose. For what moulded the particular constellation of relationships between the dialects and languages of any family was none other than the unfolding relations between the populations who spoke them, as they themselves diverged through pre- history.

Yet there was only one real-world population history, of course.

New Perspectives on Indo-European Phylogeny and Chronology

So how is it that for this same language family, different types of phylogenetic analysis can come to such radically different outputs? Is one right and the others wrong? And how might the different types of phylogenetic method-tree-only or network approaches-help us uncover what actually happened in linguistic prehistory? Linguists have traditionally represented patterns of divergence within a language family in terms of either of two discrete models by which they are assumed to arise:.

There has been much debate in theory as to the respective merits and demerits of these models, and how well suited each might be for representing the types of relationship that can obtain between language varieties within a family. What has been all too briefly considered, however, is how and why in practice these two types of relationship come to arise in the first place. How and why should it be in the nature of languages to develop into relationships of these particular and starkly contrasting types?

In truth the contrast in models only exists at all because it reflects two very different processes in the real world. Broadly speaking, these two mechanisms are as follows.

A speaker population divides, prototypically by long-distance migration sinto two or more groups, henceforth physically separated from one another. This leads to the classic language split pattern.

A speaker population expands whether suddenly or more progressively over a continuous territory, across which a degree of contact is maintained-at least at the immediate local level, and all the more strongly the shorter the distance between any two points. This leads to language divergence in a pattern of overlapping, cross-cutting waves. The nature of any given language family as either more split-like or more wave-like can thus be interpreted as effectively a linguistic record of the past, pointing to one or other of these two different mechanisms as the probable history of its speaker populations, the real-world scenario that moulded that family's particular pattern of divergence.

Let it be clear from the outset, then, what the nature of the relationship is between the divergence pattern of a language family and the real-world contexts in which its speakers lived. For this relationship is unambiguously one of cause-and-effect; and in a direction that is equally ineluctable.

Forces in the real-world context-demographic, socio-political, cultural, and so on-are the cause; they alone determine entirely the linguistic divergence effects. One must hasten to clarify that what those forces do not determine is the form and nature of whatever particular language changes arise other than in cases of contact.

Changes can be highly idiosyncratic, and generally are either random, or in line with other changes in the language system as a whole Heggartyp. Changes arise by natural linguistic processes, then; what external forces determine is only whether those changes whatever linguistic form they take either develop independently and differently, or come to be shared, from one region to the next. That is, real-world forces dictate not which particular changes occur, but the patterns of language divergence that they ultimately give rise to.

What many readers may feel is missing from the above discussion of the two divergence mechanisms is the role of borrowing or contact. It is with very good reason, however, that we leave borrowing out of this section.

For a start, borrowing and contact are modes of language con vergence of languages either unrelated, or related but already diverged from each other. As such, neither has any real place here, in this discussion of the two basic modes of language di vergence out of a common ancestor. How could those three studies come to such radically different results?

Which of the two basic mechanisms of language divergence comes closest to what actually happened to the peoples who spoke the earliest Indo-European languages? Answering those questions calls for a full exploration of the difference between a splits-then-borrowing and a dialect continuum scenario, and how significant it is for how we understand and model language prehistory.

These issues have to be left for a more wide-ranging survey than there is space for here, however, in further papers by Heggarty in preparation ab.

The treatment here will be limited to only one of the main issues in the trees versus webs debate, and seek instead to establish a more general point of methodology. For in reality, neither a branching tree nor a continuum model alone is sufficient to account for the complex relationships observed across many a language family. Nor, indeed, have we any reason to expect either to be. The vagaries of history typically ensure that in the real world, both types of process may act upon the populations speaking any given language family, combining in any manner of ways across time and space.

The real-world history of any language family need by no means be a story of uniquely one or the other mechanism, but is very often a complex composite of the two. This complexity has implications for the tools and data we might look to in order to model and represent relationships between the languages within a family. In principle, to do justice to real language divergence histories, we need a model able to capture both split and wave mechanisms within a single analysis and representation.

Indeed ideally we would wish for a model that allows us to tease apart the respective contributions of each to the overall story. The ability to do just this is precisely the claim made for one particular type of phylogenetic analysis: those of the network type, in contrast to others of the tree-only type. Though initially developed for applications in the biological sciences, particularly genetics, two network-type methods in particular have also been widely applied to language divergence data: Network and NeighborNet, both of which we shall survey here.

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It is not considered in detail here, however, firstly because it has been rather less used in linguistic studies of late. A second and more critical objection is that for precisely the task in hand here, that of teasing apart the respective strengths of tree-like and web-like signals, Split Decomposition has an inherent bias-towards the former.

It is not the task of this short article to set out in detail the workings of these methods. Useful general sources include the valuable and readable survey of and introduction to network methods, as applied specifically to language studies, in Bryant et al. Here, we just briefly overview how the two network-type methods we cover here have been received in historical linguistics, and focus on how they relate to the issue of particular interest in this paper.

The Network algorithm Bandelt et al.

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The programme can be downloaded from www. Forster in particular has applied Network to language data, in papers with various colleagues.

Criticisms of their approach to the language data and certain assumptions in the dating methodology employed are widely felt to invalidate the paper's conclusions. Rather less problematic are Forster et al. These too, though, are based on rather limited datasets. The authors remove all of these data, which in the case of Germanic leaves an effective dataset of just 28 data-points.

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Questions also remain as to the authors' inferences for what their outputs may mean for the history of the Germanic-speaking populations Forster et al. Still, however one might question the handling of the data and ancillary assumptions in any one case, such objections are besides the main methodological point for the purposes of this paper. For criticism on these scores does not impugn the algorithm per se as one that in principle does harbour considerable potential as a means of representing language divergence relationships.

Albeit on an imperfect and limited dataset, the pattern does duly reflect that cross-cutting relationships exist within Germanic-whether imputable to shared or parallel innovation, to cross-cutting waves across a dialect continuum, or to contacts between speakers after an earlier split.

Such an output format is arguably more realistic and balanced than a tree-only representation. It also has the attraction and advantage over NeighborNet of identifying all individual changes in the network diagram itself, i. Unrooted network of 19 Germanic language samples. Reproduced with permission from Forster et al. It too was first intended particularly for applications in the biological sciences, but has been enthusiastically advocated for applications to language data by a number of researchers, including April McMahon and Russell Gray, each together with various colleagues.

NeighborNet from a matrix of distances in phonetics between traditional dialects in Germanic. NeighborNet from a matrix of measures of divergence in phonetics between traditional dialects and reconstructed historical varieties of English.

Bryant et al. In both studies, the authors use traditional lexicostatistical data. We have also applied it to other, finer-grained measures of language divergence. Heggarty's study of the Andean language families Quechua and Aymara is based on distance data in lexical semantics, as calculated by a new quantification method to work to a more refined level than traditional lexicostatistics, set out in Heggartyand more briefly in McMahon et al.

We have explored NeighborNet also with divergence ratings in phoneticsfor the Romance languages Heggarty et al. Both of these network-type methods, then, are able to visualize together the relative strengths of the tree-like and web-like signals within a single dataset. This is indeed how Forster et al. In fact, even methods whose graphical outputs are only in tree format can nonetheless produce similar quantifications of tree-ness, many of them based on samples of large numbers of possible trees.

There are, however, known problems with consistency indices particularly, with actual scores overly dependent on sample size.

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One can also focus on individual branches within the tree. Other recent work takes existing tree-only approaches as a basis upon which to build what are effectively new forms of network analysis. Nakhleh et al. For Ringe et al. Much of the explanation for this apparent contradiction lies in whether one considers the entire family, throughout its history, or focuses on just its earliest divergence stages.

Some experts say that if parents and kids don't speak the same language at home, communication between them may suffer. As a result, parents may lose some control over their children and, over time, kids might turn to negative influences, such as gangs, to regain the sense of belonging they no longer experience at home. Several methods can help kids be bilingual.

In each, it's very important to expose kids to both languages in different settings and to help them understand the significance of learning each language. With any method, try not to mix the languages. That is, when you talk to your child in your heritage language, don't mix it with English in phrases or sentences. However, you shouldn't be surprised if your child mingles words of both languages in one sentence. When it happens, correct him or her by casually providing the proper word in the language you are using.

And of course, there's always the Internet.

Method of dating divergence within language families

When exposing kids to a second language, consider their hobbies. For example, if a child likes soccer, watch a match in one of the Spanish-speaking stations. If your child likes music, check for the latest albums of artists singing in English and in their native language. For young kids, use childhood rhymes, songs, and games. As your kids grow, be persistent and creative with your approach. Some parents send their kids to language schools so that they learn the language using a more formal method.

Many families also send their kids to their country of origin to spend more time with relatives, either during the summer or for longer periods. Keep in mind that it's also important to have friends who speak a heritage language.

Some of your culture and some ties are likely to be lost if your child is raised in a new country; however, it's up to you to choose whether you want to pass your cultural heritage to your kids or not.

There is, indeed, an "American" culture. However, remember that for centuries, many people who arrived in America looking for a more promising future kept their native languages and cultures at their homes and in their neighborhoods.

However, they learned to speak English and blended in with the American lifestyle. Hence, a reevaluation of the previously proposed paraphyly of Myrmeleontiformia based on other kinds of data or methods is needed [ 48 ]. Previous molecular studies of the phylogeny of Neuropterida have mostly relied on conventional measures of branch support, such as the non-parametric bootstrap [ 50 ] and the Bayesian posterior probabilities [ 51 ]. However, the usage of these measures alone has often proven insufficient for the purpose of estimating the robustness of the inferred molecular phylogenies [ 525354555657 ], especially when the size of the dataset increases [ 5859606162 ], or when overly simplified evolutionary models are used [ 6364 ].

A plethora of quartet-based approaches for estimating phylogenomic incongruence and node certainty in molecular phylogenies has been proposed lately [ 45265666768 ]. These approaches rely on the calculation of phylogenetic signal from quartets of taxa and they can be used to identify conflicting signals and potentially inflated support for certain phylogenetic clades, but have not yet been applied to the phylogeny of Neuropterida.

Given the putatively misleading nature of the existing branch support measures in a maximum likelihood or Bayesian phylogenetic framework, combined with the incongruent results of previous phylogenomic studies, a thorough evaluation of the conflicts in the phylogenetic tree of Neuropterida is currently needed.

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The purpose of this study is to provide: 1 a phylogenomic framework and ated divergence time estimates of Neuropterida, 2 an evaluation of conflicting phylogenetic signals in the backbone phylogeny of the group, and 3 a discussion of the implications for morphological character evolution within Neuropterida based on the results of the present contribution and those of other studies.

In an effort to resolve the existing incongruencies we assembled a novel transcriptomic dataset of Neuropterida and of suitable outgroup species, and assessed the robustness of our phylogenetic estimates with concatenation-based quartet approaches combined with data permutations and with gene tree-based quartet approaches.

We additionally estimated divergence times of the major lineages of Neuropterida by using an approach that enables monitoring the effect of data selection on the Bayesian posterior divergence times of Neuropterida.

On average, sequences per transcriptome or official gene set OGS passed the reciprocal best-hit criterion during the orthology assignment step max. The majority of the excluded transcriptomes and OGSs refer to outgroup taxa 17 outgroup and four ingroup species. Concatenation of the masked amino-acid sequence alignments resulted in a supermatrix composed of domain-based partitions spanning more than 1. The optimization of the partitioning scheme of supermatrix E with the software PartitionFinder resulted in a total number of meta-partitions.

Phylogenetic analyses of the domain-based partitioned amino-acid sequence data yielded congruent topologies with respect to the phylogenetic relationships of major lineages with those obtained when analyzing the second codon positions of the nucleotide sequence data Fig.

In addition, the phylogenetic trees yielded by the analyses of the reduced amino-acid supermatrices decisive and RCFV-corrected versions of supermatrix E, Table 1 are topologically congruent with trees that resulted from the analyses of the above-mentioned datasets, concerning the phylogenetic relationships within Neuropterida Additional file 3 : Figures S6-S9.

Analyses with the site-heterogeneous mixture models also delivered topologies congruent to the analyses of the above-mentioned datasets Additional file 3 : Figures SS Phylogenetic relationships of Neuropterida based on the analyses of the concatenated amino-acid sequence data of supermatrix E.

Colored circles depict phylogenetic branch support values based on non-parametric bootstrap replicates. Blue squares indicate the time-calibrated nodes. Divergence time estimates were calculated from a single summarized MCMC chain first independent analysis, run 1 that included all parameter values from each individual meta-partition analysis when including all fossil calibrations.

Insect photos from top to bottom: Dichrostigma flavipesSialis lutariaChrysopa perla all photos by O. The inferred relationships within Raphidioptera suggest the monophyly of the family Raphidiidae, and the placement of the Nearctic genus Agulla as sister to a clade comprising all the Palearctic Raphidiidae.

These relationships received maximum bootstrap and maximum bootstrap by transfer TBE support Fig.

In linguistics, a method of dating divergence in branches of language families. In language, pronouns, lower numerals, and names for body parts and natural objects. The attempt by ethnic minorities and even countries to proclaim independence by purging their . Dec 12,   2. Language divergence and the real world: two models, one reality. Linguists have traditionally represented patterns of divergence within a language family in terms of either of two discrete models by which they are assumed to arise: the splits model, corresponding to a branching family tree structure;Cited by:

Within the Palearctic Raphidiidae the genus Mongoloraphidia was inferred as the sister taxon to all remaining Raphidiidae. Within Neuroptera, a sister group relationship between Coniopterygidae and all remaining neuropteran families received maximum bootstrap and maximum TBE support Fig. A clade comprising Osmylidae, Sisyridae, and Nevrorthidae i. Osmyloidea [ 20 ] was inferred as sister to all neuropteran families except Coniopterygidae.

Dilaridae was placed as the sister group to all other Neuroptera except Coniopterygidae and Osmyloidea. A clade comprising Mantispidae and Berothidae i. Mantispoidea excluding Rhachiberothidae for which transcriptomic data were not available received high statistical branch support in all analyses of the above-mentioned analyzed datasets Fig.

A sister group relationship between Ithonidae and Myrmeleontiformia excluding Psychopsidae for which transcriptomic data were not available was inferred with maximum bootstrap and maximum TBE support. These results were congruent with the results of the summary coalescent analyses of gene partitions at the amino-acid sequence level, except for the sister group relationship of Mongoloraphidia to the remaining Palearctic Raphidiidae Fig.

Gene tree-based and concatenation-based quartet analyses of the phylogenetic relationships of Neuropterida. Pie charts on branches show ASTRAL quartet support quartet-based frequencies of alternative quadripartition topologies around a given internode. Arrows indicate the numbers of the corresponding tree nodes in Fig. The first column shows the results of FcLM when the original data of supermatrix E were analyzed.

The second column shows the results of FcLM after phylogenetic signal had been eliminated from supermatrix E i. I, see Additional file 2.

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The summary coalescent analyses and the concatenation-based analyses of gene partitions when analyzing codon-based nucleotide sequence data with all codon positions included suggest different topologies concerning the inter-familiar phylogenetic relationships of Neuroptera Additional file 3 : Figures SS29, see also Additional file 2. Additional topological differences concern the inferred relationships within Osmyloidea depending on the method and the data type analyzed e.

The different hypotheses concerning the relationships of these four groups e. Hemerobiidae vs.

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The four-cluster likelihood mapping FcLM approach delivered strong statistical support for most inferred phylogenetic relationships Additional file 1 : Table S2. Support for Coniopterygidae instead of Nevrorthidae as the sister group to the remaining Neuroptera also received strong FcLM support without detectable confounding signal Fig.

The monophyly of Osmyloidea is also strongly supported without detectable confounding signal A potential sister group relationship of Osmylidae and Chrysopidae, as suggested by some previous morphological studies, is not supported by the FcLM branch support tests Hypotheses 4a and 4b, Fig. The monophyly of Myrmeleontiformia Nymphidae, Nemopteridae, Ascalaphidae, Myrmeleontidae is strongly supported by our FcLM tests without detectable confounding signal Fig.

Nevertheless, the results of FcLM analyses showed conflicting signal for some splits in the backbone tree of Neuroptera Fig. For example, the FcLM analyses do not unequivocally support the sister group relationship of Sisyridae and Nevrorthidae i.

FcLM analyses on the permuted matrices showed that there was no substantial contribution of confounding factors for this sister group relationship, although there exists some weak signal Our molecular-dating analyses illustrate that most meta-partitions contained enough signal to overrule the prior assumptions i. Given a fixed topology and node-age calibrations, the distribution of median posterior divergence times among meta-partitions when compared with the distribution of the median values of the marginal prior distributions, constitutes evidence for the dominant influence of signal in the datasets Fig.

It does however also show extensive variation in signal among meta-partitions. This variation in signal is more prominent for certain nodes e. Distribution of the median posterior node ages among the different meta-partitions.

Arrows indicate the corresponding crown groups of Neuropterida and outgroups. Numbers on x-axis correspond to the node number ids of the tree in Fig. The distribution of the median age estimates when running the analyses without data i. There is extensive variation in signal among meta-partitions for this particular split Fig. Many consecutive deep splits in the phylogeny of Neuroptera e. Lastly, most crown groups of the different neuropterid families e. Posterior node-age estimates and confidence intervals that resulted from the combined analysis of the second independent run run 2 with MCMCTree are very similar Additional file 1 : Table S4which suggests that the two independent chains each composed of the combined parameter values of the individual meta-partitions have converged to very similar posterior node-age estimates Additional file 3 : Figures S30, S We traced the evolution of larval characters within Neuroptera based on the best topology overall best maximum likelihood tree, ML tree, Fig.

The implications for the evolution of larval characters in Neuroptera under parsimony are outlined in Additional file 1 : Table S5. Autapomorphies of Neuroptera, Myrmeleontiformia and Coniopterygidae two terminals included in the studies by Beutel et al.

With the parsimony approach the reconstruction of ancestral states remained ambiguous with respect to the larval habitat of Neuroptera terrestrial versus aquatic, Additional file 1 : Table S5. In contrast, our Bayesian stochastic character mapping SCM analyses suggest a primarily terrestrial larval habitat in the last common ancestor of Neuroptera but also in the last common ancestor of the entire Neuropterida Fig.

This result is recovered irrespective of the inferred relationships within Osmyloidea Additional file 3 : Figures SS Additionally, the parsimony-based analysis remained ambiguous with respect to the ancestral character state of the larval gula in Neuroptera.

A large posterior sclerotized plate as it is present in Nevrorthidae and also in Raphidioptera and Megaloptera may be ancestral, with a small posterior rectangular sclerite preserved as vestige in Polystoechotinae, and a small anteromedian triangular sclerite as a de novo formation in Myrmeleontiformia. The specialized terminal seta of the flagellum is interpreted as secondarily absent in Nevrorthidae on the one hand, and in Ithonidae and Myrmeleontiformia on the other, in the latter case as a potentially synapomorphic feature of these two groups.

The poison channel and the intrinsic musculature of the maxillary stylets are secondarily absent in Sisyridae [ 47 ]. The trumpet-shaped empodium is likely an apomorphy of Neuroptera excluding Coniopterygidae and Osmyloidea, and the secondary loss of this feature is a synapomorphy of Ithonidae and Myrmeleontiformia [ 47 ].

The ground plan of Neuroptera with respect to the larval cryptonephry is ambivalent. This feature could represent an apomorphy of Neuroptera Additional file 1 : Table S5. Summarized results of stochastic character mapping analyses SCM for the evolution of larval ecologies based on 10, sampled character histories. Stochastic character maps were generated under the ER model and by using the topology and branch lengths of the chronogram of Fig.

Colored circles at the tips show the coded state for each species. Pie charts on internal tree nodes show posterior probabilities of states at each node under the model used. Internal nodes with a posterior probability lower than 1. Previously published phylogenomic analyses have suggested robustly resolved backbone trees of Neuropterida [ 17202122 ] that were in part incongruent to inferred phylogenetic relationships based on analyses of morphological characters.

The most recent molecular analyses at odds with morphological analyses were based on extensive genomic data [ 202124 ] and therefore the incongruences between these molecular and morphological phylogenies cannot be easily dismissed. Since the accumulation and characterization of extensive genomic data is now the standard procedure in phylogenetics, as it is also true for the analyses of the phylogeny of Neuropterida, the evaluation of statistical robustness of the inferred phylogenies is becoming a complex yet essential task [ 69 ].

It is obvious that conventional analyses of statistical robustness, in most cases performed with the classical non-parametric bootstrap, might not scale well with the quantity of the data [ 59707172 ]. This is because bootstrap support values provide an assessment of the sampling effects and repeatability of the analyses but cannot assess the accuracy of the inferred phylogenetic trees [ 71 ].

Alternative or complementary measures of phylogenomic incongruence are warranted to identify phylogenetic relationships with potentially inflated support [ 52536873 ]. In order to identify potentially inflated branch support of the inferred relationships within Neuropterida, we have used a combination of gene tree-based and concatenation-based quartet methods and compared results with those of the classical non-parametric bootstrapping approach and with those of the newly described bootstrap by transfer support measure TBE.

We observed that a few seemingly well supported phylogenetic relationships assessed by bootstrapping are in fact inflated due to potentially confounding factors in the data. In most instances, concatenation-based and gene tree-based quartet methods deliver congruent pictures, that are in several cases in stark contrast to the classical resampling approaches. We conclude from these observations that at least parts of the backbone tree of Neuropterida should still not be considered robustly resolved.

Below we discuss two examples from the backbone tree of Neuroptera that do not receive unequivocal support from our quartet analyses:. We observed incongruent topologies between concatenation and the summary coalescent phylogenetic analyses concerning the splits within Osmyloidea.

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This incongruence between methods was only present when analyzing amino-acid sequence alignments. The analyses of the codon-based nucleotide sequence alignments with all codon positions included resulted in phylogenetic relationships congruent to the summary coalescent approach. Despite the high bootstrap and high TBE support from the concatenated analyses of amino-acid sequence data for a sister group relationship of Sisyridae and Nevrorthidae, our FcLM analyses do not unequivocally support the inferred phylogenetic relationships within Osmyloidea.

Specifically, quartet support calculated with ASTRAL and FcLM analyses show almost equal proportions of quartets supporting each of the two above-mentioned prevalent phylogenetic hypotheses. Moreover, the FcLM analyses suggest substantial influence from taxon sampling and possibly from non-random distribution of missing data for this particular phylogenetic relationship.

Putting the results of the concatenation-based, summary coalescent and FcLM analyses together, we conclude that the phylogenetic relationships of the three families in Osmyloidea should be considered for now unresolved. These incongruencies again warrant a detailed examination of potentially confounding signals. The FcLM analyses also show some weak putatively misleading signal in support of this relationship that possibly originates from non-random distribution of missing data.

Although many previous phylogenomic studies have focused on the biological causes of incongruence that results from analyzing the data with coalescent-based or concatenation-based phylogenetic methods [ 59747576 ], little attention has been given to the effects of the different analyzed data types on phylogenetic inference [ 77 ].

Such data-type effects have been discussed before either in the context of analyzing different genomic regions, such as analyzing introns vs. Here, we find that some of the inferred relationships within Neuroptera i. Given sufficient phylogenetic signal, the expectation is that the analyses of the same genomic regions at the nucleotide sequence level and the translational level should reflect the same evolutionary history.

If the analyses of different data types result in discrepancies, this is most likely due to the failure of the applied substitution models to accommodate the evolutionary history in the analyzed data. Thus, the above-mentioned data-type effects probably stem from violations of the model assumptions by the analyzed data. Additionally, the observation that these data-type effects are quite robust across different tree-inference methods further suggests that both concatenation and summary coalescent methods are sensitive to these violations of model assumptions.

An important open question is why some branches in the tree of Neuroptera may be more prone to data-type effects than others. Within holometabolous insects, Neuropterida is inferred as the sister group to Coleopterida, a phylogenetic hypothesis that is in accordance with the latest views on the phylogeny of Holometabola [ 24 ]. The notion that Megaloptera is the sister group to Neuroptera was first introduced by Boudreaux [ 83 ], on the premise of common wing venation characters.

This idea was revived later with the argument that aquatic larvae represent a synapomorphic feature for Neuroptera and Megaloptera, with secondary terrestrialization in Neuroptera [ 84 ].

Our phylogenetic results and FcLM analyses are in agreement with the results of those morphological studies and with recent phylogenomic analyses of mitochondrial genomes or target DNA enrichment data concerning the inter-ordinal relationships of Neuropterida [ 182021 ].

This node-age estimate is slightly older than the age inferred in previously published phylogenomic studies, that proposed a common origin of the extant Neuropterida in the late Carboniferous or the early Permian [ 2021 ]. Within Raphidioptera, both Raphidiidae and Inocelliidae are recovered as monophyletic in all of our analyses and with high statistical support.

Our results suggest the placement of the Nearctic genus Agulla as sister to the Palearctic Raphidiidae.

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Although the Nearctic genus Alena is not included in our analyses, the above-mentioned relationship suggests the monophyly of the Palearctic Raphidiidae and corroborates previous molecular phylogenetic analyses of Raphidiidae [ 26 ]. Furthermore, the results of the analyses of domain-based partitioned data are in agreement with previous molecular phylogenetic analyses of the Raphidiidae, that suggested the division of the Palearctic Raphidiidae into an Eastern Palearctic Mongoloraphidia clade and a Western Palearctic OhmellaPuncha and Phaeostigma clades radiation [ 26 ].

The order Megaloptera is inferred as monophyletic in all analyses and the family Corydalidae is also inferred as monophyletic. These results are congruent with the results of target DNA enrichment-based phylogenomic analyses of Neuropterida [ 20 ].

In addition, these results are in agreement with morphological analyses of genital and non-genital characters and with most morphology-based phylogenies of Neuropterida [ 91127 ]. There are only few morphological autapomorphies of Megaloptera such as the shift of the bases of the male gonocoxites 9 to the base of tergum 9 [ 36 ]. Morphological characters supporting the monophyly of Corydalidae are scarce and they concern mostly genital characters and wing-base structures [ 2736 ].

Our taxon sampling does not allow further assessment of the monophyly of the corydalid subfamilies Corydalinae and Chauliodinae, but recent phylogenetic investigations have shown that the current taxonomic classification is supported by the analyses of molecular or morphological characters [ 202736 ]. Our inferred phylogenetic trees corroborate the results of previous phylogenomic studies that suggested the family Coniopterygidae as sister to all remaining neuropteran families [ 202122 ].

The idea that the dustywings are the sister group of the remaining families of Neuroptera is very old [ 94 ] and was originally based on a number of characters that this family shares with Megaloptera, such as the reduced number of Malpighian tubules six in Coniopterygidae instead of eight in other Neuroptera and the reduced number of abdominal ganglia of their larvae [ 94 ]. However, it should be noted that these features could be the result of miniaturization in the dustywings.

Moreover, the alternative character states would be plesiomorphic, and therefore they constitute no arguments for monophyletic Neuroptera excluding Coniopterygidae. This result is in agreement with the findings of recent molecular dating analyses of Neuropterida [ 2021 ].

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The phylogenetic placement of Coniopterygidae as sister to all remaining Neuroptera is in contrast with the majority of morphological analyses that have instead suggested Nevrorthidae as the most ancient lineage within the order [ 91115 ].

The monophyly of Neuroptera with the exclusion of Nevrorthidae is morphologically supported by the formation of an undivided postmentum, the far-reaching modification or loss of the larval gula and the presence of cryptonephric Malpighian tubules of the larvae [ 15 ].

Specifically, in all terrestrial neuropteran larvae including Coniopterygidae the distal parts of the Malpighian tubules are connected with the colon, a phenomenon referred to as larval cryptonephry.

In the aquatic larva of Nevrorthus all Malpighian tubules are free, while the aquatic larvae of Sisyridae have one cryptonephric tubule.

in linguistics, a method of dating divergence in branches of language families Core Vocabulary in language, pronouns, lower numerals, and names for body parts and natural objects. Method of dating divergence within language families Linguists have seen also use the carbon method of internal reconstruction an evolutionary approach such linguistic analyses also use the rentpath family name. The latest advancements in DNA sequencing technologies have facilitated the resolution of the phylogeny of insects, yet parts of the tree of Holometabola remain unresolved. The phylogeny of Neuropterida has been extensively studied, but no strong consensus exists concerning the phylogenetic relationships within the order Neuroptera. Here, we assembled a novel transcriptomic dataset to address.

The phenomenon of cryptonephry results in an improved water re-absorption mechanism and is apparently an adaptation to terrestrial environment, especially to a more exposed lifestyle and life in drier habitats. The original idea concerning the evolution of cryptonephry within Neuroptera is in contrast with the herewith presented phylogenetic relationships and with other molecular phylogenies [ 172021 ], that suggest cryptonephry might be an apomorphic feature of Neuroptera with a putative secondary loss in Nevrothidae and secondary modification in Sisyridae.

Despite the lack of morphological autapomorphies for a clade comprising Neuroptera excluding Coniopterygidae, this robust result across molecular analyses and methods suggests that a sister group relationship of Nevrorthidae to all other neuropteran families is unlikely. A clade of Nevrorthidae, Sisyridae and Osmylidae i. Osmyloidea is inferred as sister to all remaining neuropteran families except Coniopterygidae and this clade is stable across analyses of different datasets and methods.

This clade was also strongly supported in all quartet analyses, which in turn suggests that the placement of these three families in a monophyletic group is robust. This result is also in agreement with the results of analyses of target DNA enrichment data [ 20 ]. Potential synapomorphies of Osmyloidea are the semi-aquatic or aquatic larval ecologies and the secondarily multi-segmented antennae of the larvae [ 95 ].

Within Osmyloidea, a sister group relationship of Nevrorthidae and Sisyridae is congruent with the analyses of mitochondrial genomes [ 21 ] and with older studies based on the analysis of a few genes [ 17 ]. Moreover, a single shift to an aquatic lifestyle conforms to a branching pattern of Nevrorthidae and Sisyridae as sister clades. It should, however, be noted that the larvae of Nevrorthidae and Sisyridae have very different breathing and feeding adaptations, an observation that contrasts their sister group relationship [ 95 ].

In the context of our best ML tree Fig.

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Another interesting observation in this context is that the adults of Osmylidae are the only neuropterans with ocelli. Given that the possession of ocelli is most likely a plesiomorphic feature, as they are present in the adults of Raphidiidae and Corydalidae, we can hypothesize that the median eyes must have been reduced several times independently within Neuroptera, with possible vestiges still preserved in several groups. A robust inference of the most archaic phylogenetic events within Neuroptera is essential for deciphering the evolution of lifestyle transitions of their larvae.

Aquatic versus terrestrial habits of ancestral neuropteran larvae as well as a possible ancestral aquatic larvae of Neuropterida have been discussed in detail by authors of previous studies [ 2021 ]. Specifically, previous ancestral character state reconstructions ACSR of the larval ecologies of Neuropterida have suggested that the common ancestor of Neuroptera might have had aquatic larvae [ 2021 ].

Under the scenario of primarily aquatic neuropteran larvae, the results of our transcriptomic analysis would imply that the larvae of Coniopterygidae acquired terrestrial habits secondarily. In a second step Osmylidae must also have acquired terrestrial larvae independently, and finally in a third step the stem species of the remaining Neuroptera must also have acquired terrestrial larvae. Although three independent transitions to terrestrial lifestyle within Neuroptera is a possible scenario, it is not the most parsimonious.

In an alternative scenario, with the stem species of Neuroptera being primarily terrestrial in the larval stages, the larvae of Sisyridae and Nevrorthidae would be secondarily aquatic as assumed by Gaumont [ 97 ]. Our parsimony-based ACSR of larval ecologies do not provide unequivocal support for either aquatic or terrestrial larvae in the last common ancestor of Neuroptera. In contrast, our SCM analyses unequivocally support primarily terrestrial larvae of Neuroptera and Neuropterida.

However, it should be noted that parsimony-based ACSRs suffer from a number of limitations [ 9899 ] and that our parsimony-based analysis is based on a less extensive taxon sampling [ 95 ].

For these reasons we consider the estimates of SCM analyses as more reliable.

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The hypothesis of primarily terrestrial larvae of Neuropterida and Neuroptera suggests either two or three independent shifts to aquatic larval lifestyles within Neuropterida depending on the inferred topology within Osmyloidea. We conclude from these observations that at least two shifts to aquatic habitats must have occurred in the early evolution of Neuropterida.

Some parents send their kids to language schools so that they learn the language using a more formal method. Many families also send their kids to their country of origin to spend more time with relatives, either during the summer or for longer periods. in linguistics, a method of dating divergence in branches of language families core vocabulary in language, pronouns, lower numerals, and names for body parts and natural objects. Since history often leaves a complex of both patterns within the same language family, ideally we need a single model to capture both, and tease apart the respective contributions of each. The.

The family Dilaridae pleasing lacewings has been traditionally considered to form a clade with the families Mantispidae, Berothidae and Rhachiberothidae. We could not corroborate a clade that includes these four families as suggested by other authors [ 847 ].

All analyses place Dilaridae as sister to all remaining Neuroptera except Coniopterygidae and Osmyloidea. This result is in accordance with previous sequenced-based phylogenomic analyses [ 2021 ]. Most importantly, the monophyly of the neuropteran families except Coniopterygidae and Osmyloidea is strongly supported by previous analyses of mitochondrial genomic rearrangements [ 1821 ].

Mantispidae and Berothidae were recovered as sister taxa with strong statistical branch support in all phylogenetic analyses, but the placement of this clade within Neuroptera is not robustly resolved.

Concatenation-based and summary coalescent phylogenetic analyses of amino-acid sequences suggest a sister group relationship of Mantispoidea with Chysopidae. However, the different quartet analyses did not unequivocally support this sister group relationship. Our results corroborate previous views suggesting a close phylogenetic affinity of Berothidae and Mantispidae [ 947 ].

The phylogenetic relationships within Mantispoidea, as well as the monophyly of Mantispidae, have remained unresolved [ 20 ], yet our taxon sampling does not allow testing any hypothesis concerning the phylogeny of Mantispoidea.

The conflicting phylogenetic hypotheses between the analyses of different data types presented here corroborate the results of Winterton et al.

These results are identical to our own results based on analyses of amino-acid sequence data. However, it should be noted that there is presently no morphological support in favor of these phylogenetic relationships. Morphological apomorphies shared by Hemerobiidae and Chrysopidae [ 1121 ] and the results of our quartet-based analyses show that the above-mentioned relationships require further scrutiny.

The main argument for this sister group relationship was based on length of the cardines, and the possession of special prothoracic glands [ ].

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However, varying lengths of the cardines are gradual modifications rather than discrete character states. Additionally, data on the prothoracic glands are missing for most neuropteran families.

The family Ithonidae is inferred as monophyletic and sister to monophyletic Myrmeleontiformia. The monophyly of Myrmeleontiformia is also strongly supported by our FcLM analyses and by previous analyses of morphological characters [ 1448 ]. The synapomorphies supporting the monophyly of Myrmeleontiformia, including the Psychopsidae, have already been documented by MacLeod [ 13 ], by Beutel et al. Overall, the larval cephalic morphology of Myrmeleontiformia differs profoundly from that of other groups of Neuroptera [ 1547 ], including among others the anterior shift of the tentorium and the greatly enlarged muscles of the paired mouthparts to handle the huge sucking tubes.

Our phylogenetic analyses of amino-acid sequence alignments are in contrast with the results of the analyses of target DNA enrichment data that suggested paraphyletic Myrmeleontiformia in relation to Ithonidae [ 2024 ]. Interestingly, when we analyzed codon-based nucleotide sequences with all three codon positions included, Myrmeleontiformia was rendered paraphyletic in relation to Ithonidae similarly to the results of Winterton et al.

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The study of Winterton et al. In contrast, we received high statistical support in most phylogenetic analyses and in FcLM analyses in favor of the monophyly of this group.

Within Myrmeleontiformia excluding PsychopsidaeNymphidae is inferred as the earliest diverging lineage. Larval synapomorphies of Myrmeleontiformia excluding Psychopsidae are the conspicuously raised ocular region, a sensory pit on the apical labial palpomere, a strongly developed mid-dorsal cervical apodeme, a distinctly widened body posterior to the prothorax, and a compact and laterally rounded abdomen [ 1547 ]. The monophyly of the family Nemopteridae has been questioned before [ ], but has been corroborated later [ 14 ].

These results are congruent with those of most recent cladistic analyses of Myrmeleontiformia based on analyses of larval characters [ 48 ]. However, non-parametric bootstrap support for the monophyly of Myrmeleontidae in the analyses of amino-acid sequence alignments was very low, and the same applies for the gene tree-based quartet support for this particular phylogenetic relationship.

Previous phylogenomic analyses of the owlflies and antlions have suggested that Myrmeleontidae are polyphyletic with respect to Ascalaphidae [ 2024 ]. Based on that premise, it has been suggested that Ascalaphidae should be placed in a subfamily of Myrmeleontidae together with the antlion tribes Palparini, Dimarini and Stilbopterygini [ 24 ]. Since we did not recover Ascalaphidae nested within Myrmeleontidae, we retain the taxonomic status of Ascalaphidae as a separate family.

The monophyly of the Myrmeleontidae has been corroborated based on several fossorial habits of their larvae and specific features linked with them [ 1448 ]. It is essential to mention that the different phylogenetic relationships of neuropteran families presented here corroborate previous results on the evolution of the larval gula-like sclerite within Neuroptera [ 20 ].

Winterton et al. The result showed that the presence of gula is the ancestral state of the entire Neuropterida clade. As such, the presence of gula in the larvae of Nevrorthidae, Ithonidae, and Myrmeleontiformia could be formed either by numerous multiple losses in other lacewings, or could have at least two independent gains in these groups. When considering the larval gula in Myrmeleontiformia, this sclerite is usually reduced to a narrow sclerite medially dividing the two greatly enlarged genal sclerites, a structure that appears different from the gula in Megaloptera and Raphidioptera.

Our parsimony-based character mapping analysis suggested an independent gain of the gula-like sclerite in the members of Ithonidae and Myrmeleontiformia similarly to the suggestion by Winterton et al. Because the herewith presented phylogenetic incongruencies mainly concern the phylogenetic position of Hemerobiidae, Chrysopidae and Mantispoidea and because the larvae of these groups lack a gula-like sclerite, the previously suggested pattern for the evolution of this morphological feature is unaffected by our results.

Hence, an independent gain or reinvention of this gula-like sclerite in Ithonidae and in Myrmeleontiformia appears very likely. We draw four major conclusions from our analyses: 1 Part of the backbone tree of Neuropterida receives strong statistical support in several independent phylogenetic analyses and should be considered for now the most likely scenario of neuropterid evolution.

Within Neuroptera, all analyses support an early split between Coniopterygidae and the remaining Neuroptera which cannot be corroborated with morphological analyses.

The families Nevrorthidae, Sisyridae and Osmylidae form a monophyletic group sister to all other Neuroptera except Coniopterygidae. The family Dilaridae is the sister group to all remaining Neuroptera except Coniopterygidae and Osmyloidea. Despite these seemingly robust phylogenetic results, the phylogenetic relationships between the most species rich groups of Neuroptera i.

For several branches in the neuropteran tree, the seemingly high branch support appears to be inflated and should be taken with caution. Scientists are therefore advised to critically evaluate branch support in phylogenomic analyses and assume a conservative position.

However, parts of the backbone tree of Neuropterida can still not be robustly resolved which is disappointing, but reflecting a picture seen in other analyses of ancient phylogenetic splits as well. It will be necessary to invest molecular data beyond primary gene sequence information, for example structural genomic data [ 59].

Morphological analyses are critically needed to deliver a complete picture of the evolution of Neuropterida. We sequenced and de novo assembled 88 whole-body transcriptomes of 85 species of Neuropterida Raphidioptera: 18 species, Megaloptera: seven species, Neuroptera: 60 species, Additional file 1 : Table S6comprising representatives of all extant families of Neuropterida except Rhachiberothidae and Psychopsidae.

For the species Parvoraphidia microstigmaPalpares libelluloidesPeyerimhoffina gracilistwo transcript libraries of separate specimens were generated respectively, sequenced and assembled Suppl Table 1.

RNA isolation, RNA library preparation, transcriptome sequencing, transcriptome assembly, and transcriptome quality assessment were performed according to the procedures described by Misof et al. We complemented our dataset with publicly available transcriptomic and genomic official gene sets, OGS sequence data of eight neuropterid and 41 outgroup species, representing all currently recognized holometabolous insect orders Additional file 1 : Table S7.

In total, our sampling comprised 96 transcriptomes of Neuropterida from 92 species and 45 transcriptomes and official gene-sets of non-neuropterid insects from 41 species, see Additional file 2. Holometabolabased on a custom profile query in OrthoDB7 [ ] see Additional file 2 for details.

The custom query allowed COGs only to be included in the ortholog set if single-copy genes of all selected reference taxa were present in a given COG. As reference genomes, we selected Acromyrmex echinatior v. Mapping of putative orthologous transcripts to each COG, at the translational amino-acid, aaCOGs and at the transcriptional level nucleotide, nCOGswas performed with the software package Orthograph v. Subsequently, we selected a subset of outgroup and ingroup species with a high number of assigned orthologs for downstream analyses Additional file 1 : Table S1.

We did not exclude ingroup taxa based on their completeness measured by the number of assigned orthologsexcept in those cases in which more than one transcriptome from the same species were used in the orthology assignment step.

Overall, we considered transcriptomes of the outgroup species to be of high completeness when putative orthologous transcripts from these datasets were assigned to at least COGs Additional file 1 : Table S1, with the exception of Mengenilla moldrzyki.

The filtered dataset consisted of species 92 neuropterid species and 32 outgroup species including the four reference species of the ortholog set. We followed the procedures outlined by Misof et al.

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