The mitochondrial genome of Nobia grandis Sowerby, 1839 (Cirripedia: Sessilia): the first report from the coral-inhabiting barnacles family Pyrgomatidae

Complete mitochondrial genome of the European common barnacle Perforatus perforatus Bruguière, 1789 (balanomorpha: balanidae)

This study is the first to sequence the complete mitochondrial genome (mitogenome) of Perforatus perforatus Bruguière, 1789 (Balanomorpha: Balanidae). The 15,536-bp long P. perforatus mitogenome contained a typical set of animal mitochondrial genes, along with one control region. The P. perforatus mitogenome had an inverted gene block (trnP-ND4L-ND4-trnH-ND5-trnF) between trnS(gct) and trnT. This inverted gene block had been detected six species in three subfamilies of the Balanidae family (Balaninae, Acastinae and Megabalaninae), but our results show that it is also present in Concavinae, in which P. perforatus is included. The phylogenetic tree based on the concatenated sequences of the 13 protein-coding genes and two rRNA genes showed that P. perforatus is closely associated with Acasta sulcate and Balanus trigonus within Balanidae.

The Mitochondrial Genome of the Globally Invasive Barnacle Megabalanus coccopoma Darwin 1854 (Crustacea: Balanomorpha): Rearrangement and Phylogenetic Consideration within Balanomorpha

Megabalanus coccopoma (Darwin, 1854) is a globally invasive species in Balanomorpha (Crustacea). This species is a model organism for studying marine pollution and ecology. However, its mitogenome remains unknown. The mitogenome sequencing of M. coccopoma is completed in the present study. It has a 15,098 bp in length, including 13 protein-coding genes (PCGs), 2 ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs), along with a putative regulatory area. A substantial A+T bias was observed in the genome composition (68.2%), along with a negative AT (0.82) and GC (−0.136) skew. Compared to the gene sequence of the ground model of pan-crustacea, 13 gene clusters (or genes), such as 10 tRNAs and 3 PCGs, were observed in a different order. This was in line with the previously observed large-scale gene rearrangements of Balanomorpha. Among the 37 genes, the gene cluster (M-nad2-W-cox1-L2-cox2-D-atp8-atp6-cox3-G- nad3-R-N-A-E-S1) Balanomorpha was conserved. Furthermore, phylogeny analysis indicated that the existing Balanomorpha species family was divided into nine rearrangement patterns, supporting the polyphyly of Balanoidea.

Complete mitochondrial genome of Tetraclita squamosa squamosa (Sessilia: Tetraclitidae) from China and phylogeny within Cirripedia

Here we present the complete mitochondrial genome of Tetraclita squamosasquamosa, which is 15,191 bp in length with 67.20% AT content. It contains 13 protein-coding genes, 2 ribosomal-RNA genes and 22 transfer-RNA genes. All PCGs except nad4l in T. squamosasquamosa start with ATN, and terminated with a complete stop codon, except nad3. Phylogenetic analysis based on mitochondrial PCGs shows that T. squamosasquamosa is clustered with T. serrata into a branch (BP = 100). Our result is consistent with previous reports that genus Tetraclita and family Tetraclitidae are not monophyletic. This study contributes to further phylogenetic analysis within Cirripedia. 

The complete mitochondrial genome of Tetraclita japonica (Crustacea: Maxillopoda: Sessilia) from Zhejiang (China) and phylogeny within Sessilia

The complete mitochondrial genome of Tetraclita japonica (Crustacea: Maxillopoda: Sessilia) from Zhejiang (China) was presented (T. japonica ZJ). The genome is a circular molecule of 15,192 bp, all non-coding regions are 694 bp in length, and the longest one (307 bp) is located between 12S rRNA and trnK. Phylogenetic analysis based on mitochondrial PCGs shows that T. japonica ZJ clusters with T. japonica CN, and they grouped with T. japonica (BP = 100), then grouped with Tesseropora rosea, Tetraclita serrata, Tetraclita rufotincta, Epopella plicata, and Tetraclitella divisa successively . The phylogenetic tree indicated that the Balanidae and Archaeobalanidae are polyphyletic, while the Chthamalidae is monophyletic. The result can help us to understand the phylogenetic history within Sessilia.

The first mitochondrial genome of Megabalanus tintinnabulum (Sessilia: Balanidae) from China: phylogeny within Cirripedia based on mitochondrial genes

Here we present the complete mitochondrial genome of Megabalanus tintinnabulum. The genome is 15,107 bp in length with a 67.35% AT content. It contains 13 protein-coding genes (PCGs), 2 rRNAs genes, and 22 tRNAs. Both rRNAs are encoded on the light strand, as in the other crustacean and barnacle mitochondrial genomes. Besides five tRNAs are encoded on the light strand (nad1, trnV, trnL1, trnC, trnQ, and trnK). Only one PCG is encoded on the light strand (nad1), whereas the other 12 PCGs are located on the heavy strand, which is consistent with M. ajax. Phylogenetic analysis based on mitochondrial PCGs shows that M. tintinnabulum is clustered with M. ajax into a branch (BP = 100), and the group with M. volcano with high support. This study contributes to further phylogenetic analysis within Cirripedia.

Mitochondrial genome of Tesseropora rosea: molecular evidence for non-monophyly of the genus Tetraclita

The complete mitochondrial genome of Tesseropora rosea (Tetraclitidae) was presented. The genome is a circular molecule of 15,330 bp, which encodes 13 PCGs, two rRNA genes, and 22 tRNA genes. The length of all non-coding regions is 768 bp, with the longest one speculated as the control region (255 bp), which is located between 12S rRNA and trnK. Phylogenetic analysis based on mitochondrial PCGs shows that T. rosea is nested within the genus Tetraclita, more closely related to Tetraclita japonica than to Tetraclita rufotincta or Tetraclita serrata. Thus, the monophyly of the genus Tetraclita is not supported.