The land snail Ellobium chinense (L. Pfeiffer, 1855) (Eupulmonata, Ellobiida, Ellobiidae), which inhabits the salt marshes along the coastal areas of northwestern Pacific, is an endangered species on the IUCN Red List. Over recent decades, the population size of E. chinense has consistently decreased due to environmental interference caused by natural disasters and human activities. Here, we provide the first assessment of the genetic diversity and population genetic structures of northwestern Pacific E. chinense . The results analyzed with COI and microsatellites revealed that E. chinense population exhibit metapopulation characteristics, retaining under the influence of the Kuroshio warm currents through expansion of the Late-Middle and Late Pleistocene. We also found four phylogenetic groups, regardless of geographical distributions, which were easily distinguishable by four unidirectional and stepwise adenine-to-guanine transitions in COI (sites 207–282–354–420: A–A–A–A, A–A–G–A, G–A–G–A, and G–G–G–G). Additionally, the four COI hotspots were robustly connected with a high degree of covariance between them. We discuss the role of these covariate guanines which link to form four consecutive G-quadruplexes, and their possible beneficial effects under positive selection pressure.

Gobioidei is one of the largest vertebrate taxa with over 2000 species observed around the globe. The largest group in Gobioidei is gobies that had been classified as one family, Gobiidae, based on morphological features. Molecular phylogenetic studies revealed that gobies consisted of two monophyletic families, Gobiidae and Oxudercidae, in which 19 lineages have been proposed, despite some claims arisen about the relationship among these lineages or species. We analyzed 58 Gobioidei species, including 45 East Asian oxudercids, based on 12S rRNA sequences to reconstruct the spatiotemporal diversification history of gobies. Our analysis yielded the results compatible with the previous reports in a large framework. The common ancestor of Gobiidae and Oxudercidae were estimated to appear at 38.66 Mya. Genus-level splits occurred in Gobiidae and Oxudercidae predominantly at Miocene and late Miocene to early Pleistocene, respectively. Gobies have likely originated in many parts of the northern and western Pacific Ocean, of which a large proportion of Oxudercidae have adapted to various environments in the North Pacific.

Scrophularia species are highly valued and widely used traditional medicinal plants in East Asia. In this article, the complete chloroplast genome of Scrophularia cephalantha, a species endemic to South Korea, is reported for the first time. The genome is 153,016 bp long, and it is composed of a pair of 25,485 bp inverted repeats (IRs), separated by a large single copy (LSC) region of 84,124 bp, and a small single copy (SSC) region of 17,922 bp. There are 133 predicted genes in the genome, comprising 88 protein-coding genes, 37 tRNAs, and 8 rRNAs, with an overall GC content of 38%. Phylogenetic analysis based on the chloroplast genome data showed that S. cephalantha is a sister species to S. buergeriana and S. ningpoensis. The data provide useful molecular information for phylogenetic and evolutionary studies of the genus Scrophularia and its related species.

We performed high-throughput sequencing on the complete mitogenomes of two Araneidae species, a wasp spider (Argiope bruennichi) and a large nocturnal spider (Araneus ventricosus). The two mitogenomes contain 14,060 bp and 14,607 bp, and GC content of 26.6% and 26.5%, respectively. The two mitogenomes contain 13 protein-coding genes (PCGs), 22 transfer RNAs, 2 ribosomal RNAs, and 1 control region. We performed a phylogenetic analysis with the concatenated 13 PCGs, which showed that Argiope and Araneus are clearly classified and clustered within Araneidae clade. Our study serves to enrich evolutionary and ecological studies.

Plumarella spinosa (Anthozoa: Octocorallia: Primnoidae) is an endangered marine soft coral species discovered on a 50–100 m deep reefs in South Korea. We analyzed the mitochondrial genome sequence of this species. The genome size was 19,037 bp in length consisting of 14 protein coding genes (PCGs), two rRNA genes and a tRNA gene. Our phylogenetic analysis for this species with 33 Octocorallia species reconstructed based on the nucleotide sequences of 14 PCGs showed that P. spinosa was placed as a sister to Narella hawainensis and Primnoidae formed a monophyletic group.

We performed high-throughput sequencing on the complete mitogenomes of two non-orb-weaving spiders, Pardosa astrigera (wolf spiders; Lycosidae) and Agelena labyrinthica (funnel weaver; Agelenidae). The two mitogenomes contain 14,520 bp and 14,772 bp, and a GC content of 22.5% and 25.5%, respectively. The two mitogenomes contain 13 protein-coding genes (PCGs), 22 transfer RNAs, two ribosomal RNAs, and one control region. Phylogenetic analysis of the concatenated 13 PCGs revealed the clear classification of the two families, based on the data of this study.

Two individuals of Latrodectus hesperus Chamberlin & Ivie were newly found in munitions storage at military facilities in Daegu, South Korea. A female was first discovered on August 31, 2018, and followed by another female along with three egg sacs on September 20, 2018. These spiders were identified based on morphological characters and DNA barcode sequence analysis. Additional surveys were made around the initial detection site to examine the range and spread of this species, but no additional individuals were found.

The complete mitochondrial genome sequence from the Asian crested ibis, Nipponia nippon (Aves, Pelecaniformes, Threskiornithidae), was determined and characterized in detail. This mitochondrial genome is 16,813?bp long, and consists of 13 PCGs, 22 tRNAs, and 2 rRNAs. The nucleotide composition is slightly biased with A?+?T contents of 53.79% (A, T, C, and G was 30.37%, 23.42%, 31.99%, and 14.22%, respectively). 11 PCGs are initiated by ATN codons, except for cox1 and cox2 with GTG instead. The phylogenetic relationships based on the maximum-likelihood and Bayesian methods showed that the placement of N. nippon within the order Pelecaniformes, with forming the monoclade of the family Threskiornithidae.

The complete mitochondrial genomes of Luciogobius grandis and Luciogobius elongatus (Perciformes, Gobionellinae) living on rocky coasts in South Korea are reported here for the first time. The mitogenomes of L. grandis and L. elongatus have total lengths of 16,477 bp and 16,486 bp, respectively, and include 13 PCGs, small and large rRNAs, a control region, and 22 tRNAs. Most of the genes are encoded on the heavy strand except for nine genes. Compared with other Gobionellinae species, the PCGs of the two Luciogobius species have a conserved gene order. These data provide useful molecular information for phylogenetic studies concerning Luciogobius species and related species.

The complete mitochondrial genome of Ellobium chinense (Ellobioidea, Ellobiidae), an Endangered species in South Korea, is reported here for the first time. The mitogenome of E. chinense is 13,979 base pairs in total length and includes 13 PCGs, small and large rRNAs, and 21 tRNAs. Twelve genes are encoded on the light-strand and 24 genes on the heavy-strand. Compared to four other ellobiid species, the PCGs of E. chinense have a conserved gene order except for the positions of ND4L and ND4. These data provide useful molecular information for phylogenetic studies concerning ellobiids and related species.

Copepods, small aquatic crustaceans, are the most abundant metazoan zooplankton and outnumber every other group of multicellular animals on earth. In spite of ecological and biological importance in aquatic environment, their morphological plasticity, originated from their various lifestyles and their incomparable capacity to adapt to a variety of environments, has made the identification of species challenging, even for expert taxonomists. Molecular approaches to species identification have allowed rapid detection, discrimination, and identification of cryptic or sibling species based on DNA sequence data. We examined sequence variation of a partial mitochondrial cytochrome C oxidase I gene (COI) from 133 copepod individuals collected from the Korean Peninsula, in order to identify and discriminate 94 copepod species covering six copepod orders of Calanoida, Cyclopoida, Harpacticoida, Monstrilloida, Poecilostomatoida and Siphonostomatoida. The results showed that there exists a clear gap with ca. 20 fold difference between the averages of within-specific sequence divergence (2.42%) and that of between-specific sequence divergence (42.79%) in COI, suggesting the plausible utility of this gene in delimitating copepod species. The results showed, with the COI barcoding data among 94 copepod species, that a copepod species could be distinguished from the others very clearly, only with four exceptions as followings: Mesocyclops dissimilis-Mesocyclops pehpeiensis (0.26% K2P distance in percent) and Oithona davisae-Oithona similis (1.1%) in Cyclopoida, Ostrincola japonica-Pseudomyicola spinosus (1.5%) in Poecilostomatoida, and Hatschekia japonica-Caligus quadratus (5.2%) in Siphonostomatoida. Thus, it strongly indicated that COI may be a useful tool in identifying various copepod species and make an initial progress toward the construction of a comprehensive DNA barcode database for copepods inhabiting the Korean Peninsula.

The mulberry white caterpillar, Rondotia menciana, belongs to the lepidopteran family Bombycidae, in which the domestic silkworm, Bombyx mori is included. In this study, we describe the complete mitochondrial genome of R. menciana in terms of general genomic features and characteristic features found in the A+T-rich region. The 15,364 bp long genome consisted of a typical set of genes (13 protein-coding genes [PCGs], 2 rRNA genes, and 22 tRNA genes) and 1 major non-coding A+T-rich region, with the typical arrangement found in Lepidoptera. Twelve of the 13 PCGs started with typical ATN codons, except for the COI, which began with CGA and twelve of 13 PCGs had complete stop codons, except for the COII, which ended with a single T. The 360 bp long A+T-rich region harbored the conserved sequence blocks typically found in lepidopteran insects. Additionally, the A+T-rich region of R. menciana contained one tRNA(Met)-like structure, which had a proper anticodon and secondary structure.

The complete mitochondrial genome of Ridgeia piscesae (Polychaeta, Siboglinidae), one of the dominant taxa in deep-sea hydrothermal vents, is reported here for the first time. The R. piscesae mitogenome is 15,002bp in total length and includes 13 protein-coding gene sequences, small and large rRNA sequences and 22 tRNA sequences. All genes are encoded on the heavy strand. The mitochondrial genomes of R. piscesae and other six polychaete species have a conserved gene order.

In this study, we determined the complete mitogenome sequence of Siberian stone loach, Barbatula toni (Dybowsky, 1869). The total length of mitogenome is 16 623 bp, which consists of 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region (D-loop). The genome organization and gene order were identical to that of the typical vertebrates. The control region harbors conserved sequence blocks (CSB-D, E, F, CSB-1, CBS-2 and CBS-3) and TA-nucleotide microsatellite repeats in its 3' end. The complete mitogenome may provide important molecular data for further phylogenetic analyses for higher taxa of teleost fishes, especially for the fishes in order Cypriniformes.

The complete mitochondrial genome of Odontobutis interrupta (Perciformes, Odontobutidae), a species endemic to South Korea, is reported here for the first time. The O. interrupta mitogenome is 16 802 base pairs in total length and includes 13 PCGs, small and large rRNAs, a control region and 22 tRNAs. Nine genes are encoded on the light strand and 29 on the heavy strand. The O. interrupta mitochondrial genome has a conserved gene order compared to four other Odontobutis species and Micropercops swinhonis, a closely related species. The data will provide useful molecular information for phylogenetic studies concerning Odontobutidae and its related species.

The complete mitochondrial genome of Hymeniacidon sinapium (Demospongiae, Halichondriidae) is reported here for the first time. The H. sinapium mitogenome is 23,435 base pairs in total length and includes 14 protein-coding gene sequences, small and large rRNA sequences, and 25 tRNA sequences. All genes are encoded on the heavy strand without overlapping genes.