Characterization of the First Complete Mitochondrial Genome of Cyphonocerinae (Coleoptera: Lampyridae) with Implications for Phylogeny and Evolution of Fireflies

A Mysterious Asian Firefly Genus, Oculogryphus Jeng, Engel & Yang (Coleoptera, Lampyridae): The First Complete Mitochondrial Genome and Its Phylogenetic Implications

The firefly genus Oculogryphus Jeng, Engel & Yang, 2007 is a rare-species group endemic to Asia. Since its establishment, its position has been controversial but never rigorously tested. To address this perplexing issue, we are the first to present the complete mitochondrial sequence of Oculogryphus, using the material of O. chenghoiyanae Yiu & Jeng, 2018 determined through a comprehensive morphological identification. Our analyses demonstrate that its mitogenome exhibits similar characteristics to that of Stenocladius, including a rearranged gene order between trnC and trnW, and a long intergenic spacer (702 bp) between the two rearranged genes, within which six remnants (29 bp) of trnW were identified. Further, we incorporated this sequence into phylogenetic analyses of Lampyridae based on different molecular markers and datasets using ML and BI analyses. The results consistently place Oculogryphus within the same clade as Stenocladius in all topologies, and the gene rearrangement is a synapomorphy for this clade. It suggests that Oculogryphus should be classified together with Stenocladius in the subfamily Ototretinae at the moment. This study provides molecular evidence confirming the close relationship between Oculogryphus and Stenocladius and discovers a new phylogenetic marker helpful in clarifying the monophyly of Ototretinae, which also sheds a new light on firefly evolution.

An Overview of Aquatica Fu et al., a Phylogeny of Aquatic Fireflies Using Mitochondrial Genomes, a Description of Two New Species, and a New Record of Aquatic Fireflies in China (Coleoptera: Lampyridae: Luciolinae)

There are now seven species in the genus Aquatica Fu & Ballantyne, with all but one known from the characteristics of males, females, and larvae. Molecular information is combined with morphological taxonomy for the delimitation of both genus and species. The monophyly of the genus Aquatica is strongly supported in six trees, and its position as sister to the genus Nipponoluciola Ballantyne Kawashima Jusoh et Suzuki is stable across maximum likelihood and Bayesian inference results. Two new species of Aquatica Fu & Ballantyne, A. qingshen sp. nov. and A. xianning sp. nov., described from the features of males, females, and larvae, are closely related within a single clade within the genus Aquatica. Females have distinctively shaped median oviduct plates. A Chinese population identified as A. lateralis was found to be morphologically similar to the Japanese population, but genetic distances suggest that it is a distinctive species. No larvae are associated with this species. Definitions of the aquatic status of Luciolinae fireflies are expanded.

A Phylogenetic Morphometric Investigation of Interspecific Relationships of Lyponia s. str. (Coleoptera, Lycidae) Based on Male Genitalia Shapes

The nominate subgenus Lyponia Waterhouse, 1878 from China is reviewed, with two new species described and named L. (s. str.) ruficeps sp. n. (China, Yunnan) and L. (s. str.) zayuana sp. n. (China, Xizang). A distribution map and a key to all species of Lyponia s. str. are provided. Moreover, the phenotypic relationships among the species of Lyponia s. str. are investigated based on phallus shapes using geometric morphometric and phylogenetic morphometric analyses. The topologies demonstrate that the species are divided into two clades. One clade is composed of six species (L. ruficeps sp. n., L. zayuana sp. n., L. kuatunensis, L. shaanxiensis, L. hainanensis, and L. tamdaoensis) and is supported by a stout phallus (less than 3.6 times longer than wide). The other clade includes the remaining species (L. nepalensis, L. debilis, L. cangshanica, L. delicatula, and L. oswai) and is supported by a slender phallus (at least 4.1 times longer than wide). These results provide better understanding of the species diversity and evolution of Lyponia s. str. Nonetheless, more samples and loci are required in the future to verify the present results.

Comparative Mitogenomic Analyses of Darkling Beetles (Coleoptera: Tenebrionidae) Provide Evolutionary Insights into tRNA-like Sequences

Tenebrionidae is widely recognized owing to its species diversity and economic importance. Here, we determined the mitochondrial genomes (mitogenomes) of three Tenebrionidae species (Melanesthes exilidentata, Anatolica potanini, and Myladina unguiculina) and performed a comparative mitogenomic analysis to characterize the evolutionary characteristics of the family. The tenebrionid mitogenomes were highly conserved with respect to genome size, gene arrangement, base composition, and codon usage. All protein-coding genes evolved under purifying selection. The largest non-coding region (i.e., control region) showed several unusual features, including several conserved repetitive fragments (e.g., A+T-rich regions, G+C-rich regions, Poly-T tracts, TATA repeat units, and longer repetitive fragments) and tRNA-like structures. These tRNA-like structures can bind to the appropriate anticodon to form a cloverleaf structure, although base-pairing is not complete. We summarized the quantity, types, and conservation of tRNA-like sequences and performed functional and evolutionary analyses of tRNA-like sequences with various anticodons. Phylogenetic analyses based on three mitogenomic datasets and two tree inference methods largely supported the monophyly of each of the three subfamilies (Stenochiinae, Pimeliinae, and Lagriinae), whereas both Tenebrioninae and Diaperinae were consistently recovered as polyphyletic. We obtained a tenebrionid mitogenomic phylogeny: (Lagriinae, (Pimeliinae, ((Tenebrioninae + Diaperinae), Stenochiinae))). Our results provide insights into the evolution and function of tRNA-like sequences in tenebrionid mitogenomes and contribute to our general understanding of the evolution of Tenebrionidae.

Comparative genome and phylogenetic analysis revealed the complex mitochondrial genome and phylogenetic position of Conopomorpha sinensis Bradley

Conopomorpha sinensis Bradley is a destructive pest that causes severe economic damage to litchi and longan. Previous C. sinensis research has focused on population life tables, oviposition selectivity, pest population prediction, and control technology. However, there are few studies on its mitogenome and phylogenetic evolution. In this study, we sequenced the whole mitogenome of C. sinensis by the third-generation sequencing, and analyzed the characteristics of its mitogenome by comparative genome. The complete mitogenome of C. sinensis is a typical circular and double-stranded structure. The ENC-plot analyses revealed that natural selection could affect the information of codon bias of the protein-coding genes in the mitogenome of C. sinensis in the evolutionary process. Compared with 12 other Tineoidea species, the trnA-trnF gene cluster of tRNA in the C. sinensis mitogenome appears to have a new arrangement pattern. This new arrangement has not been found in other Tineoidea or other Lepidoptera, which needs further exploration. Meanwhile, a long AT repeated sequence was inserted between trnR and trnA, trnE and trnF, ND1 and trnS in the mitogenome of C. sinensis, and the reason for this sequence remains to be further studied. Furthermore, the results of phylogenetic analysis showed that the litchi fruit borer belonged to Gracillariidae, and Gracillariidae was monophyletic. The results will contribute to an improved understanding of the complex mitogenome and phylogeny of C. sinensis. It also will provide a molecular basis for further research on the genetic diversity and population differentiation of C. sinensis.

The first complete mitochondrial genome of Matsucoccidae (Hemiptera, Coccoidea) and implications for its phylogenetic position

The mitochondrial genome (mitogenome) has been extensively used to better understand the phylogenetic relationships within the hemipteran suborder Sternorrhyncha, but sequenced mitogenomes remain unavailable for the entire family Matsucoccidae to date. To address this, here we sequenced the complete mitogenome of Matsucoccusmatsumurae; the first for this family. The mitogenome is 15,360 bp in size and comprises the typical set of 37 mitochondrial genes and a large non-coding region (AT-rich region). Gene order, nucleotide composition and codon usage of protein-coding genes (PCGs) of M.matsumurae differ considerably from those of the other two sequenced Coccidae species. All PCGs were initiated by the ATN start codons and ended with the TAA/G or single T-- stop codons. Nine transfer RNA genes could be folded into typical clover-leaf secondary structures. The length and AT content of the ribosomal RNA genes are highly conserved in the Coccoidea mitogenomes. In contrast, the AT-rich control region is highly variable in size and in the number of tandem repeats. The sliding window analysis showed that the cox1 gene is the most conserved amongst the 13 PCGs, while the ratios of non-synonymous to synonymous substitution rates indicated that the evolution of this mitogenome has been dominated by positive selection. Phylogenetic analyses, based on nucleotide sequence data of 37 mitochondrial genes and amino acid sequence data of 13 PCGs using Bayesian Inference and Maximum Likelihood methods, showed that Matsucoccidae diverged before the Coccidae.

Rhagophthalmidae Olivier, 1907 (Coleoptera, Elateroidea): described genera and species, current problems, and prospects for the bioluminescent and paedomorphic beetle lineage

Rhagophthalmidae are a small beetle family known from the eastern Palaearctic and Oriental realms. Rhagophthalmidae are closely related to railroad worms (Phengodidae) and fireflies (Lampyridae) with which they share highly modified paedomorphic females and the ability to emit light. Currently, Rhagophthalmidae include 66 species classified in the following 12 genera: Bicladodrilus Pic, 1921 (two spp.), Bicladum Pic, 1921 (two spp.), Dioptoma Pascoe, 1860 (two spp.), Diplocladon Gorham, 1883 (two spp.), Dodecatoma Westwood, 1849 (eight spp.), Falsophrixothrix Pic, 1937 (six spp.), Haplocladon Gorham, 1883 (two spp.), Menghuoius Kawashima, 2000 (three spp.), Mimoochotyra Pic, 1937 (one sp.), Monodrilus Pic, 1921 (two spp. in two subgenera), Pseudothilmanus Pic, 1918 (two spp.), and Rhagophthalmus Motschulsky, 1854 (34 spp.). The replacement name Haplocladongorhami Kundrata, nom. nov. is proposed for Diplocladonhasseltii Gorham, 1883b (described in subgenus Haplocladon) which is preoccupied by Diplocladonhasseltii Gorham, 1883a. The genus Reductodrilus Pic, 1943 is tentatively placed in Lampyridae: Ototretinae. Lectotypes are designated for Pseudothilmanusalatus Pic, 1918 and P.marginalis Pic, 1918. Interestingly, in the eastern part of their distribution, Rhagophthalmidae have remained within the boundaries of the Sunda Shelf and the Philippines demarcated by the Wallace Line, which separates the Oriental and Australasian realms. This study is intended to be a first step towards a comprehensive revision of the group on both genus and species levels. Additionally, critical problems and prospects for rhagophthalmid research are briefly discussed.

Mitochondrial genomes of Sternochetus species (Coleoptera: Curculionidae) and the phylogenetic implications

The three weevil species, Sternochetus gravis, S. mangiferae, and S. olivieri, have all been reported to be serious pests of mango fruits. Morphology, biology, and various management approaches of these economically important weevils have been well studied. However, no mitochondrial genomes have been reported from the genus Sternochetus. Herein, we assembled mitogenomes of all the three Sternochetus species to reveal their mitogenomic characteristics. A DNA library of 350 bp insert size was constructed and sequenced in Illumina's HiSeq 6000 platform with a pair-end 150 bp sequencing strategy by Novogene. The sequence reads were assembled using GetOrganelle v1.7.1 and the genes were annotated by Geneious Prime 2021.0.3 and MITOS Web Server. Coupled with 61 published mitogenomes from 13 subfamilies of Curculionidae, we reconstructed phylogenetic trees to resolve evolutionary relationships of these closely related species and also examined subfamily-level classification among Curculionidae. All three mitogenomes are double-stranded circular molecules with 22 transfer RNA genes, 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, and 1 noncoding control region as in other insects. Higher interspecific nucleotide divergence (about 10%) of 13 PCGs indicated these three Sternochetus species diverged a long time ago. Phylogenetic analyses using both maximum likelihood and Bayesian inference methods showed that Sternochetus falls into the basal clade of Cryptorhynchini, a tribe in the subfamily Molytinae. The relationship of S. olivieri as a sister species to S. gravis + S. mangiferae was strongly supported. The monophyly of Cryptorhynchini was also well supported whereas Molytinae was suggested to be a polyphyletic group.