东方小藤壶Chthamalus challengeri（甲壳动物亚门：无柄目）线粒体基因组：小藤壶科基因排列比较及藤壶亚目系统发育分析

藤壶是潮间带生态、幼体发育以及生物防污损研究中重要的模式生物。目前，线粒体基因组学的发展有助于从线粒体基因组水平上更好地理解系统发育关系。本研究获得东方小藤壶Chthamalus challengeri完整线粒体基因组，大小为15358bp的环状分子。与藤壶亚目其它物种相比，东方小藤壶非编码区的长度较长，而基因区的长度则相近。东方小藤壶线粒体基因组A+T含量为70.5%。现有藤壶物种的线粒体基因组中存在起始和终止密码子的变化。同属的东方小藤壶和触肢小藤壶C. antennus具有共同的基因排列。然而，小藤壶科中不同属之间却具有不同的基因排列，包括两个tRNA基因出现易位，一个基因块出现倒置。值得注意的是，与以往藤壶亚目物种不同，小藤壶属两个物种的srRNA和lrRNA基因都在重链上编码。小藤壶科中进化树的拓扑结构与基因排列证据相互支持，系统发育分析表明小藤壶科是单系群，而藤壶科和古藤壶科则是多系群。

Mitochondrial genome of Chthamalus challengeri (Crustacea: Sessilia): gene order comparison within Chthamalidae and phylogenetic consideration within Balanomorpha

Acorn barnacles are important model species in researches on intertidal ecology, larval development and biofouling. At present, with the development of mitochondrial genomics, it is helpful to understand the phylogenetic relationship from the mitogenomic level. The complete mitochondrial genome of Chthamalus challengeri was presented. The genome is a circular molecule of 15 358 bp. Compared with other species in Balanomorpha, the non-coding region is longer, while the length of the genes is similar to the other species. The overall A+T content of the mitochondrial genome of C. challengeri is 70.5%. There are variations of initiation and stop codons in the known Balanomorpha mitochondrial genomes. The C. challengeri and C. antennatus within the same genus share the identical gene arrangement. However, the gene arrangement of different genera in Chthamalidae is different,as there is a translocation between two tRNA genes and an inversion involving a large gene block. In particular,both srRNA and lrRNA of the two species in Chthamalus are encoded in the heavy strand, differing from the former Balanomorpha species. The topology and gene arrangement in Chthamalidae support each other.Phylogenetic analysis indicates that the Chthamalidae is monophyletic, while the Balanidae and Archaeobalanidae are polyphyletic.