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The imaginal stages and eggs of the species Labiobaetis ancoralis Shi and Tong (2014) are first described and photographed based on reared materials from mature nymphs. In addition, its COI gene is sequenced and compared to other species in the same genus. Besides its nymphal labrum with submarginal spatulate-like bristles, abdomen with anchor-shaped markings, its imaginal diagnostic characteristics include slim hindwings with an indistinct costal process, and a cone-like projection between two base-widened forceps. The COI gene sequence of this species is close to L. atrebatinus. The morphological details provided in this research show that the males of the species L. ancoralis, like typical baetids, have reduced hindwings and penes, which have very limited value in classification, but their shapes of forceps can be used in future studies to identify the potentially diverse Chinese Labiobaetis species. [ABSTRACT FROM AUTHOR]

The mature larva of a new species, Neoephemera projecta sp. n.,from China is described in detail. It represents a new country record of thegenus for China. The discovery shows that the genus Neoephemera McDunnoughhas a more extensive Holarctic distribution than previously known. Ecologicalvicariance instead of geographic isolation is therefore favoured as presumedcause of the origin of the three neoephemerid genera. [ABSTRACT FROM AUTHOR]

A new species, Rhithrogena trispina sp. n. from Tian-Mu-Shan Mountainof Southeast China, is described and figured in detail at the imaginal stage.From the position of gonopore on the penis lobe, it belongs to the znojkoi -group. [ABSTRACT FROM AUTHOR]

Abstract: The mayfly species Siphluriscus chinensis (Siphluriscidae) has valuable structures useful for phylogeny reconstruction, given its putative basal position within the Ephemeroptera. Here its nearly complete mitochondrial genome is sequenced. We built phylogenetic trees through multiple analytical strategies with some other insect mitogenomes. Structurally, the obtained mitochondrial genome of S. chinensis is 16,616bp in length, 1 [1] Sequence data from this article have been deposited with the GenBank Data Libraries under Accession No. HQ875717. containing 37 genes and an extra trnK-like (trnK2 (AAA)) gene. The 12 PCGs start with typical ATN codons, except the nad1 gene which starts with an unnormalized TTG. Like other known mayfly mitogenomes, the strand bias has negative AT-skew and negative GC-skew. Phylogenetically, our topologies suggest that Odonata is the basally diverged clade in Pterygota; Ephemeroptera is the sister group of the Neoptera; and S. chinensis is indeed the most basal mayfly branch. [Copyright &y& Elsevier]

The genus Epeorus Eaton, 1881 is diverse in China but has never been specifically studied before. In this revision, eight species in Epeorus (Proepeorus) from China are recognised, including two new species, Epeorus (Proepeorus) gibbussp. nov., Epeorus (Proepeorus) falcatussp. nov. and additional five new records for this country. Both new species have unique shape of imaginal penis and tubercles on nymphal terga. The variation of Epeorus (Proepeorus) in China shows this subgenus may not be a monophyletic taxon. [ABSTRACT FROM AUTHOR]

The genus Paegniodes Eaton, 1881 and its type species P. cupulatus (Eaton, 1871) have never been described in detail completely. In this article, all stages are described and photographed. Compared to other heptageniid genera, the adults of P. cupulatus have a more colourful body, smaller hindwings but larger titillators. The nymphs of this species have no setae or tubercles on the body and no emarginations on the head capsule. They have smaller lamellae of the first gills, a wider labrum with a median notch, mandibles without setae on outer margins, maxillae with a row of setae and scattered setae on the ventral surface, cerci with mesal setae, and a median filament with setae on both sides. Both imaginal and nymphal stages of the genus have unique characters, so the taxon Paegniodes is recognized at the rank of genus here. It appears closely related to Rhithrogena Eaton, 1881. [ABSTRACT FROM AUTHOR]

The nymphs of Chankagenesia yangi (Hsu, 1936) are described for the first time and selected key structures of adults are clarified. Compared to the valid congener C. natans Buldovsky, the nymphs of C. yangi have spines on lateral large projections of frons and more in between them. In the same structure of adults, the lateral projections of C. yangi are smaller and blunter. The nymphs described here confirm the status of the species and show that the genus has a vast distribution. [ABSTRACT FROM AUTHOR]

Mayflies (Ephemeroptera) display many primitive characters and a unique type of metamorphosis (Prometabola). However, information on the genomes and transcriptomes of this insect group is limited. The RNA sequencing study presented here generated the first de novo transcriptome assembly of Cloeon viridulum (Ephemeroptera: Baetidae), and compared gene expression signatures among the young larva (YL), mature larva (ML), subimago (SI), and imago (IM) stages of this mayfly. The transcriptome, based on 88 Gb of sequence data, comprised a set of 81,185 high quality transcripts. The number of differentially expressed genes (DEGs) in YL vs. ML, ML vs. SI, and SI vs. IM, was 4,825, 1,584, and 1,278, respectively, according to the reads per kilobase of transcript per million mapped reads analysis, assuming a false discovery rate <0.05 and a fold change >2. Gene enrichment analysis revealed that these DEGs were enriched in the “chitin metabolic process”, “germ cell development”, “steroid hormone biosynthesis”, and “cutin, suberine, and wax biosynthesis” pathways. Finally, the expression pattern of a selected group of candidate signature genes for Prometabola, including vestigial, methoprene-tolerant, wingless, and broad-complex were confirmed by quantitative real time-PCR analysis. The Q-PCR analysis of larval, subimaginal, and imaginal stages of C. viridulum suggests that the development of mayflies more closely resembles hemimetamorphosis than holometamorphosis. [ABSTRACT FROM AUTHOR]

The complete mitochondrial genome ofPaegniodes cupulatus(Ephemeroptera: Heptageniidae), which is sequenced for the first time here, is 15,715 bp in length, containing 13 protein-coding genes, 2 rRNAs, 22 tRNAs and a control region. The overall base composition of the genome is 33.1% for T, 20.7% for C, 32.5% for A and 13.7% for G, with an AT bias of 65.6%. [ABSTRACT FROM AUTHOR]