Xingyue Liu

The First Mitochondrial Genome for the Fishfly Subfamily Chauliodinae and Implications for the Higher Phylogeny of Megaloptera

Megaloptera are a basal holometabolous insect order with larvae exclusively predacious and aquatic. The evolutionary history of Megaloptera attracts great interest because of its antiquity and important systematic status in Holometabola. However, due to the difficulties identifying morphological apomorphies for the group, controversial hypotheses on the monophyly and higher phylogeny of Megaloptera have been proposed. Herein, we describe the complete mitochondrial (mt) genome of a fishfly species, Neochauliodes punctatolosus Liu & Yang, 2006, representing the first mt genome of the subfamily Chauliodinae. A phylogenomic analysis was carried out based on the mt genomic sequences of 13 mt protein-coding genes (PCGs) and two rRNA genes of nine Neuropterida species, comprising all three orders of Neuropterida and all families and subfamilies of Megaloptera. Both maximum likelihood and Bayesian inference analyses highly support the monophyly of Megaloptera, which was recovered as the sister of Neuroptera. Within Megaloptera, the sister relationship between Corydalinae and Chauliodinae was corroborated. The divergence time estimation suggests that stem lineage of Neuropterida and Coleoptera separated in the Early Permian. The interordinal divergence within Neuropterida might have occurred in the Late Permian.

Early Evolution and Historical Biogeography of Fishflies (Megaloptera: Chauliodinae): Implications from a Phylogeny Combining Fossil and Extant Taxa

Fishflies (Corydalidae: Chauliodinae) are one of the main groups of the basal holometabolous insect order Megaloptera, with ca. 130 species distributed worldwide. A number of genera from the Southern Hemisphere show remarkably disjunctive distributions and are considered to be the austral remnants or “living fossils” of Gondwana. Hitherto, the evolutionary history of fishflies remains largely unexplored due to limited fossil record and incomplete knowledge of phylogenetic relationships. Here we describe two significant fossil species of fishflies, namely Eochauliodes striolatus gen. et sp. nov. and Jurochauliodes ponomarenkoi Wang & Zhang, 2010 (original designation for fossil larvae only), from the Middle Jurassic of Inner Mongolia, China. These fossils represent the earliest fishfly adults. Furthermore, we reconstruct the first phylogenetic hypothesis including all fossil and extant genera worldwide. Three main clades within Chauliodinae are recognized, i.e. the Dysmicohermes clade, the Protochauliodes clade, and the Archichauliodes clade. The phylogenetic and dispersal-vicariance (DIVA) analyses suggest Pangaean origin and global distribution of fishflies before the Middle Jurassic. The generic diversification of fishflies might have happened before the initial split of Pangaea, while some Gondwanan-originated clades were likely to be affected by the sequential breakup of Pangaea. The modern fauna of Asian fishflies were probably derived from their Gondwanan ancestor but not the direct descendents of the Mesozoic genera in Asia.

Mitochondrial phylogenomics illuminates the evolutionary history of Neuropterida

Neuroptera (lacewings) and allied orders Megaloptera (dobsonflies, alderflies) and Raphidioptera (snakeflies) are predatory insects and together make up the clade Neuropterida. The higher‐level relationships within Neuropterida have historically been widely disputed with multiple competing hypotheses. Moreover, the evolution of important biological innovations among various Neuropterida families, such as the origin, timing and direction of transitions between aquatic and terrestrial habitats of larvae, remains poorly understood. To investigate the origin and diversification of lacewings and their allies, we undertook phylogenetic analyses of mitochondrial genomes of all families of Neuropterida using Bayesian inference, maximum likelihood and maximum parsimony methods. We present a robust, fully resolved phylogeny and divergence time estimation for Neuropterida with strong statistical support for almost all nodes. Mitochondrial sequence data are typified by significant compositional heterogeneity across lineages, and parsimony and models assuming homogeneous rates did not recover Neuroptera as monophyletic. Only a model accounting for compositional heterogeneity (i.e. CAT‐GTR) recovered all orders of Neuropterida as monophyletic. Significant findings of the mitogenomic phylogeny include recovering Raphidioptera as sister to Megaloptera plus Neuroptera. The sister family of all other lacewings are the dusty‐wings (Coniopterygidae), rather than Nevrorthidae. Nevrorthidae are instead returned to their traditional position as the sister group of the spongilla‐flies (Sisyridae) and closely related to Osmylidae. Our divergence time analysis indicates that the Mesozoic was indeed a ‘golden age’ for lacewings, with most families of Neuropterida diverging during the Triassic and Jurassic and all extant families present by the Early Cretaceous. Based on ancestral character state reconstructions of larval habitat we evaluate competing hypotheses regarding the life style of early neuropteridan larvae as either aquatic or terrestrial.

The first mitochondrial genomes of antlion (Neuroptera: Myrmeleontidae) and split-footed lacewing (Neuroptera: Nymphidae), with phylogenetic implications of Myrmeleontiformia.

In the holometabolous insect order Neuroptera (lacewings), the cosmopolitan Myrmeleontidae (antlions) are the most species-rich family, while the closely related Nymphidae (split-footed lacewings) are a small endemic family from the Australian-Malesian region. Both families belong to the suborder Myrmeleontiformia, within which controversial hypotheses on the interfamilial phylogenetic relationships exist. Herein, we describe the complete mitochondrial (mt) genomes of an antlion (Myrmeleon immanis Walker, 1853) and a split-footed lacewing (Nymphes myrmeleonoides Leach, 1814), representing the first mt genomes for both families. These mt genomes are relatively small (respectively composed of 15,799 and 15,713 bp) compared to other lacewing mt genomes, and comprise 37 genes (13 protein coding genes, 22 tRNA genes and two rRNA genes). The arrangement of these two mt genomes is the same as in most derived Neuroptera mt genomes previously sequenced, specifically with a translocation of trnC. The start codons of all PCGs are started by ATN, with an exception of cox1, which is ACG in the M. immanis mt genome and TCG in N. myrmeleonoides. All tRNA genes have a typical clover-leaf structure of mitochondrial tRNA, with the exception of trnS1(AGN). The secondary structures of rrnL and rrnS are similar with those proposed insects and the domain I contains nine helices rather than eight helices, which is common within Neuroptera. A phylogenetic analysis based on the mt genomic data for all Neuropterida sequenced thus far, supports the monophyly of Myrmeleontiformia and the sister relationship between Ascalaphidae and Myrmeleontidae.

Phylogeny of the family Sialidae (Insecta: Megaloptera) inferred from morphological data, with implications for generic classification and historical biogeography

Sialidae (alderflies) is a family of the holometabolous insect order Megaloptera, with ca. 75 extant species in eight genera distributed worldwide. Alderflies are a group of “living fossils” with a long evolutionary history. The oldest fossil attributed to Sialidae dates back to the Early Jurassic period. Further, the global distribution of modern‐day species shows a remarkably disjunctive pattern. However, due to the rareness of most species and scarcity of comprehensive taxonomic revisions, the phylogeny of Sialidae remains largely unexplored, and the present classification system is in great need of renewal. Here we reconstruct the first phylogeny for Sialidae worldwide based on the most comprehensive sampling and broadest morphological data ever presented for this group of insects. All Cenozoic alderflies belong to a monophyletic clade, which may also include the Early Jurassic genus †Dobbertinia, and the Late Jurassic genus †Sharasialis is their putative sister taxon. Two subfamilies of Sialidae are proposed, namely †Sharasialinae subfam. nov. and Sialidinae. Austrosialis is the sister of all other extant genera, an assemblage which comprises three monophyletic lineages: the Stenosialis lineage, the Ilyobius lineage, and the Sialis lineage. The revised classification of Sialidae is composed of 12 valid genera and 87 valid species. Ilyobius and Protosialis are recognized as valid generic names, while Nipponosialis is treated as a synonym of Sialis. Reconstruction of the ancestral area proposes a global distribution of alderflies in Pangaea before their diversification. The generic diversification of alderflies might have occurred before the breakup of Pangaea, but the divergence of some lineages or genera was probably promoted by the splitting of this supercontinent.

Phylogeny of the subfamily Chauliodinae (Megaloptera: Corydalidae), with description of a new genus from the Oriental Realm

Abstract A new Oriental fishfly genus, Sinochauliodesgen.n., is described, including four species: S. fujianensis ( Yang & Yang, 1999 ) comb.n., S. griseus ( Yang & Yang, 1999 ) comb.n., S. maculosussp.n. and S. squalidussp.n. A cladistic analysis based on adult morphological characters clarified the phylogenetic status of the new genus and allowed the reconstruction of the intergeneric relationships of the subfamily Chauliodinae. Two main clades within Chauliodinae were recognized from the cladistic analysis. The Asian fishflies, together with the two Nearctic genera, Chauliodes and Nigronia, formed a monophyletic lineage, and the new genus was assigned as the sister group to the genus Parachauliodes. The biogeography of the Asian fishflies is discussed.

Homology of the genital sclerites of Megaloptera (Insecta: Neuropterida) and their phylogenetic relevance†

The genitalia of Megaloptera are crucial for taxonomic identification and represent a significant component of characters for phylogenetic interpretation of this order. However, several complex genital structures, especially those related to segments 9 and 11 in Megaloptera, have yet to be subjected to a comprehensive survey of homology. The terminology for genital sclerites has been variously and even incorrectly used by different authors, a fact which could lead to much confusion about character evolution. In this paper, we first present a comprehensive morphological comparison of the sclerites of male and female genital segments in 23 megalopteran genera representing all major lineages of Corydalinae, Chauliodinae and Sialidae. Accordingly, we then provide new interpretations on the homology of the genital sclerites which often appear to be considerably different among Megaloptera. Based on our new and revised homology assessments, we conclude that: (i) the small to medium‐sized sclerite beneath the ectoprocts in males of Sialidae represents the fused gonocoxites 11; (ii) the male gonocoxites 11 in Corydalidae are largely reduced and are sometimes retained as a small sclerite beneath the anus; (iii) the predominant sternite‐like sclerite of the female abdominal segment 8 represents the fused gonocoxites 8; and (iv) a pair of sclerites amalgamated with the lateral arms of male gonocoxites 10 in Chauliodinae is the gonocoxites 9. Furthermore, based on our genital homology assessments, we reconstruct an intergeneric phylogeny including all genera of Megaloptera using genital characters in a parsimonious analysis to test their phylogenetic relevance. The phylogeny herein recovered is largely congruent with the results from several previous studies, thus underlying the significant phylogenetic relevance of the megalopteran genital sclerites. The present work provides new insights into the evolution of insect genitalia.

A new genus of mantidflies discovered in the Oriental region, with a higher‐level phylogeny of Mantispidae (Neuroptera) using DNA sequences and morphology

A remarkable new genus and two new species of Mantispidae (Neuroptera) are described from the Oriental region. Allomantispa Liu, Wu, Winterton & Ohl gen.n., currently including A. tibetana Liu, Wu & Winterton sp.n. and A. mirimaculata Liu & Ohl sp.n. The new genus is placed in the subfamily Drepanicinae based on a series of morphological characteristics and on the results of total evidence phylogenetic analyses. Bayesian and Parsimony analyses were undertaken using three gene loci (CAD, 16S rDNA and COI) combined with 74 morphological characters from living and fossil exemplars of Mantispidae (17 genera), Rhachiberothidae (two genera) and Berothidae (five genera), with outgroup taxa from Dilaridae and Osmylidae. The resultant phylogeny presented here recovered a monophyletic Mantispidae with †Mesomantispinae sister to the rest of the family. Relationships among Mantispidae, Rhachiberothidae and Berothidae support Rhachiberothidae as a separate family sister to Mantispidae. Within Mantispidae, Drepanicinae are a monophyletic clade sister to Calomantispinae and Mantispinae. In a combined analysis, Allomantispa gen.n. was recovered in a clade comprising Ditaxis McLachlan from Australia, and two fossil genera from the Palaearctic, †Promantispa Panfilov (Kazakhstan; late Jurassic) and †Liassochrysa Ansorge & Schlüter (Germany; Jurassic), suggesting a highly disjunct and relictual distribution for the family.

The first mitochondrial genome for caddisfly (insecta: Trichoptera) with phylogenetic implications.

The Trichoptera (caddisflies) is a holometabolous insect order with 14,300 described species forming the second most species-rich monophyletic group of animals in freshwater. Hitherto, there is no mitochondrial genome reported of this order. Herein, we describe the complete mitochondrial (mt) genome of a caddisfly species, Eubasilissa regina (McLachlan, 1871). A phylogenomic analysis was carried out based on the mt genomic sequences of 13 mt protein coding genes (PCGs) and two rRNA genes of 24 species belonging to eight holometabolous orders. Both maximum likelihood and Bayesian inference analyses highly support the sister relationship between Trichoptera and Lepidoptera.

Evolution of lacewings and allied orders using anchored phylogenomics (Neuroptera, Megaloptera, Raphidioptera)

Analysis of anchored hybrid enrichment (AHE) data under a variety of analytical parameters for a broadly representative sample of taxa (136 species representing all extant families) recovered a well‐resolved and strongly supported tree for the higher phylogeny of Neuropterida that is highly concordant with previous estimates based on DNA sequence data. Important conclusions include: Megaloptera is sister to Neuroptera; Coniopterygidae is sister to all other lacewings; Osmylidae, Nevrorthidae and Sisyridae are recovered as a monophyletic Osmyloidea, and Rhachiberothidae and Berothidae were recovered within a paraphyletic Mantispidae. Contrary to previous studies, Chrysopidae and Hemerobiidae were not recovered as sister families and morphological similarities between larvae of both families supporting this assumption are reinterpreted as symplesiomorphies. Relationships among myrmeleontoid families are similar to recent studies except Ithonidae are placed as sister to Nymphidae. Notably, Ascalaphidae render Myrmeleontidae paraphyletic, again calling into question the status of Ascalaphidae as a separate family. Using statistical binning of partitioned loci based on a branch‐length proxy, we found that the diversity of phylogenetic signal across partitions was minimal from the slowest to the fastest evolving loci and varied little over time. Ancestral character‐state reconstruction of the sclerotization of the gular region in the larval head found that although it is present in Coleoptera, Raphidioptera and Megaloptera, it is lost early in lacewing evolution and then regained twice as a nonhomologous gula‐like sclerite in distantly related clades. Reconstruction of the ancestral larval habitat also indicates that the ancestral neuropteridan larva was aquatic, regardless of the assumed condition (i.e., aquatic or terrestrial) of the outgroup (Coleopterida).