The complete mitochondrial genome of Meretrix lusoria (Bivalvia: Veneroida: Veneridae) from Kumamoto, Japan.

We sequenced and assembled the complete mitochondrial genome sequence of the Meretrix lusoria, from Kumamoto, Japan. The length of mitogenome is 20,180 bp, including 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNA genes. The nucleotide composition of the mitogenome was 25.73% for A, 42.41% for T, 9.35% for C, and 22.49% for G. The AT and GC skewness of mitogenome sequence are -0.245 and 0.412, showing the T-skew and G-skew. The reconstructed phylogenetic relationships of 25 Bivalvia species based on 12 protein-coding genes were highly supported and the clade of all Meretrix clams included had a support value of 99%. Our results shall provide a better understanding in the evolutionary histories of the Veneroida and relative species.

The complete mitochondrial genome of Montipora aequituberculata (Scleractinia, Acroporidae).

The complete mitogenome of the hexacorallia, Montipora aequituberculata has been amplified and sequenced. The mitogenome consists of 17,886 bp, with 13 protein-coding genes, 2 ribosomal RNA genes, 2 transfer RNA genes and a control region. It has been observed that ND5 gene is split into two parts by a large fragment of genes, which commonly presented in scleractinian coral. The overall base composition of the H-strand was A, 24.91%; G, 24.1%; C, 14.2%; and T, 36.8%, with a slight AT bias of 61.7%. The control region was 627 bp in length and located between 12S rRNA and COIII gene. Based on the neighbour-joining (NJ) tree, M. aequituberculata was grouped with M. cactus, Anacropora matthai and Acropora tenuis, and formed a clade of Acroporidae. In conclusion, the complete mitogenome of M. aequituberculata data may provide more informative for phylogenetic approach for corals phylogeny.

Complete mitochondrial genome of the palemargin grouper Epinephelus bontoides (Pisces: Perciformes).

The complete mitogenome of the palemargin grouper, Epinephelus bontoides, was presented in this study. This mitochondrial genome consists of 16 903 bp, follow the typical gene arrangement with 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and a non-coding control region (CR). The overall base composition was A, 28.7%; G, 16.1%; C, 28.0%; and T, 27.2%. The control region was 1200 bp in length, which located between tRNAPro and tRNAPhe, rich in A + T (69.2%) content. Based on the Neighbor-Joining (NJ) tree, E. bontoides was grouped with E. trimaculatus, E. quoyanus, E. areolatus, and E. bleekeri, and then combined with E. merra formed a clade. This complete mitogenome of E. bontoides can provide essential phylogenetic information of Epinephelus.

DNA barcoding reveals that the common cupped oyster in Taiwan is the Portuguese oyster Crassostrea angulata (Ostreoida; Ostreidae), not C. gigas.

The Pacific cupped oyster, Crassostrea gigas, is one of the major aquacultural shellfish species that has been introduced to Europe and America from its native source in the West Pacific. In Taiwan, the cultivated cupped oysters along the west coast have been identified as C. gigas for over centuries; however, several molecular phylogenetic studies have cast doubt upon the existence of this species in Taiwan and adjacent waters. Indeed, our analyses of mitochondrial cytochrome oxidase I (COI) sequences from 313 Crassostrea collected from 12 locations along Taiwanese and southern Chinese coastlines confirm that all samples were the Portuguese oyster, C. angulata, rather than C. gigas. Multiple lines of evidence, including haplotypic and nucleotide diversity of the COI gene, demographic history, and population genetics, suggest that Taiwanese C. angulata is unique, probably experienced a sudden population expansion after the Last Glacial Maxima around 20,000 years ago, and has a significantly limited genetic connectivity across the Taiwan Strait. Our study applies an extended sampling and DNA barcoding to confirm the absence of C. gigas in natural and cultivated populations in Taiwan and southern China, where we only found C. angulata. We highlight the importance of conserving the gene pool of the C. angulata population in Taiwan, particularly considering the current threats by large-scale environmental disturbances such as marine pollution, habitat destruction, and climate change.

Complete mitochondrial genome of Junceella fragilis (Gorgonacea, Ellisellidae).

In this article, the complete mitogenome of the Octocorallia, zooxanthellate, Junceella fragilis has been amplified and sequenced. This mitochondrial genome consists of 18,724 bp, with 14 protein-coding genes, 2 ribosomal RNA genes, 1 transfer RNA genes, no intron was observed. It has been observed that a mitochondrial mismatch repair (mtMutS) gene was present in all octocorals. The overall base composition of the heavy strand was A, 29.1%; G, 20.4%; C, 33.0%; and T, 17.5%, with a slight AT bias of 62.1%. The complete mitogenomic data may provide more informative for phylogenetic approach for soft corals phylogeny especially for octocorallian species.

The complete mitochondrial genome of Conus tulipa (Neogastropoda: Conidae).

The complete mitogenome sequence of the cone snail Conus tulipa (Linnaeus, 1758) has been sequenced by next-generation sequencing method. The assembled mitogenome is 16,599 bp in length, including 13 protein-coding genes, 22 transfer RNA genes and 2 ribosomal RNA genes. The overall base composition of C. tulipa is 28.7% A, 15.2% C, 18.4% G and 37.7% T. It shows 81.1% identity to the cone snail C. consors, 78.5% to C. borgesi and 77.5% to C. textile. Using the 13 protein-coding genes and 2 ribosomal RNA genes of C. tulipa in this study, together with 18 other closely species, we constructed the species phylogenetic tree to verify the accuracy and utility of new determined mitogenome sequence. The complete mitogenome of the C. tulipa provides an essential and important DNA molecular data for further phylogeography and evolutionary analysis for cone snail phylogeny.

Complete mitochondrial genome of the sixblotch hind Cephalopholis sexmaculata (Pisces: Perciformes).

The complete mitogenome of the sixblotch hind, Cephalopholis sexmaculata was presented in this study. This mitochondrial genome consists of 16,589 bp, with 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and a noncoding control region (CR), and its gene arrangement is identical to most vertebrates. The overall base composition of the heavy strand is A, 29.35%; G, 16.08%; C, 28.56%; and T, 26.01%. The COI gene started with GTG codon and the ATP6 gene started with CTG codon. The complete mitogenomic data may provide informative for further phylogenetic approach of species of Cephalopholis and related genera belong to the Epinephelidae groupers.

Mitochondrial DNA sequence of Conus textile (Neogastropoda: Conidae).

The cone snail Conus textile belongs to the family Conidae. It is a kind of molluscivorous species. The complete mitochondrial DNA sequence was constructed by next-generation sequencing in this study. The mitogenome of C. textile is 15,765 bp in length, including 13 protein-coding genes, 22 tRNA genes, 2 ribosomal RNA genes and 1 control region. The base composition was 27.3% A, 37.9% T, 15.7% C and 19.1% G. The phylogenetic tree of C. textile with the other 6 Conus species and 15 Neogastropoda sea snails was built. It provides fundamental data for further research of phylogeny and biogeography with this genus.

The complete mitochondrial genome of Conus capitaneus (Neogastropoda: Conidae).

The complete mitochondrial genome sequence of cone snail Conus capitaneus, a kind of worm-hunting sea snails, was performed by next-generation sequencing. The mitogenome is 15,829 bp in length, including 13 protein-coding genes, 22 tRNA genes, 2 ribosomal RNA genes (12S and 16S rRNA) and 1 control region. It has an overall base composition of A (25.6%), T (36.6%), C (16.3%) and G (21.5%). It shows 79.8% identity with C. tribblei, which also belongs to worm-hunting sea snail. The phylogenetic analysis was conducted with 21 closely related species to assess their phylogenetic relationship. The complete mitogenome of the C. capitaneus provides important DNA molecular data for further phylogeography.

The complete mitochondrial genome of Conus striatus (Neogastropoda: Conidae).

Conus striatus is a kind of piscivorous cone snail. We have sequenced it by next generation sequencing method. We used de novo assembly and reference mapping methods to assemble mitogenome. The mitochondrial genome is 15,738 bp, containing 13 protein coding genes, 22 transfer RNAs and 2 ribosomal RNAs genes. The overall base composition of C. striatus is 25.9% for A, 16.3% for C, 20.8% for G and 38.6% for T. The phylogenetic analysis was conducted with 18 related species and confirmed the classification status. The complete mitogenome of the C. striatus provides an essential and important DNA molecular data for further phylogeography and evolutionary analysis for cone snail phylogeny.

Complete mitochondrial genome of the amphidromous, red-tailed goby Sicyopterus lagocephalus (Pallas) (Teleostei, Gobiidae).

In this article, the complete mitogenome of the amphidromous, red-tailed goby, Sicyopterus lagocephalus has been amplified and sequenced by long polymerase chain reaction. This mitochondrial genome consists of 16,500 bp, with 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and a non-coding control region (CR), and its gene arrangement is identical to those of most vertebrates. The CR (841 bp) is located between tRNA(Pro) and tRNA(Phe). The overall base composition of the heavy strand is A, 28.9%; G, 16.4%; C, 28.3%; and T, 26.4%, with a slight AT bias of 55.3%. The complete mitogenomic data may provide more informative for phylogenetic approach for gobioid phylogeny especially for Sicydiine gobies.

Unusual distribution of floating seaweeds in the East China Sea in the early spring of 2012.

Floating seaweeds play important ecological roles in offshore waters. Recently, large amounts of rafting seaweed have been observed in the East China Sea. In early spring, juveniles of commercially important fish such as yellowtail accompany these seaweed rafts. Because the spatial distributions of seaweed rafts in the spring are poorly understood, research cruises were undertaken to investigate them in 2010, 2011, and 2012. Floating seaweed samples collected from the East China Sea during the three surveys contained only Sargassum horneri. In 2010 and 2011, seaweed rafts were distributed only in the continental shelf and the Kuroshio Front because they had become trapped in the convergence zone of the Kuroshio Front. However, in 2012, seaweed was also distributed in the Kuroshio Current and its outer waters, and massive strandings of seaweed rafts were observed on the northern coast of Taiwan and on Tarama Island in the Ryukyu Archipelago. Environmental data (wind, currents, and sea surface height) were compared among the surveys of 2010, 2011, and 2012. Two factors are speculated to have caused the unusual distribution in 2012. First, a continuous strong north wind produced an Ekman drift current that transported seaweed southwestward to the continental shelf and eventually stranded seaweed rafts on the coast of Taiwan. Second, an anticyclonic eddy covering northeast Taiwan and the Kuroshio Current west of Taiwan generated a geostrophic current that crossed the Kuroshio Current and transported the rafts to the Kuroshio Current and its outer waters. Such unusual seaweed distributions may influence the distribution of fauna accompanying the rafts.