Analyzing the mitochondrial 16S gene from specimens collected along the Brazilian coast, we expanded the current genetic diversity and phylogeny of the Christmas tree hydroid, Pennaria disticha Goldfuss, 1820 complex. A total of seven clades were retrieved, of which three were recovered among the newly added specimens—two were already known from different locations in previous studies and a new one was formed by a specimen collected near an isolated coastal island in the São Paulo state—demonstrating that P. disticha also represents a complex of cryptic species in the southwestern Atlantic. Species delimitation analyses recovered three to five clades as separate species within P. disticha; moreover, the haplotype network confirmed the already suggested scenario of multiple invasive trajectories and helped untangle the genetic relationships between clades. The data presented herein, besides broadening P. disticha genetic diversity, reinforce the importance of barcoding analyses of local populations in cryptic species studies.

中文翻译：

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Pennaria disticha Goldfuss，1820（Cnidaria，Hydrozoa）复合体的遗传多样性：来自巴西的新见解

分析了沿巴西海岸收集的标本中的线粒体16S基因，我们扩展了当前的遗传多样性和系统发育的圣诞树水体Pennaria disticha Goldfuss，1820复合体。总共检索了7个进化枝，其中3个在新添加的标本中被回收-在以前的研究中，两个标本已在不同位置被发现，而新标本由在圣保罗州一个孤立的沿海岛屿附近收集的标本组成-证明了P. disticha在西南大西洋也代表了一个隐性物种的复合体。物种定界分析将三到五个进化枝分离为P. disticha中的一个物种; 此外，单倍型网络证实了已经提出的多种侵袭轨迹的方案，并有助于弄清进化枝之间的遗传关系。本文提出的数据，除了拓宽了斑节对虾的遗传多样性外，还加强了在隐性物种研究中对当地种群进行条形码分析的重要性。