ABSTRACT

Molecular phylogeny based on concatenated sequences of chloroplast atpB, psaA, psbA, psbC and rbcL genes indicates that the filamentous brown alga Pilinia rimosa is phylogenetically distant from the Ectocarpales, in which it has been classified (as Waerniella lucifuga). In the tree, Pilinia was sister to the clade comprised of Ishige and Petroderma (Ishigeales) supported by high statistical values. Observations of unialgal P. rimosa cultures originating from Helgoland (Germany), England (UK), Woods Hole (USA) and Newfoundland (Canada) showed a direct type of life history with reproduction by characteristic unilocular zoidangia typically forming only four zoids. Despite the description of plurilocular zoidangia in Kuckuck’s account as well as in later publications, we conclude that those observations were based on misinterpretation of the very small unilocular zoidangia formed in series, often with longitudinal walls between zoidangia. Pilinia rimosa grows in caves or crevices in rocks, and on walls or wood pilings in deep shade in the upper intertidal and spray zone, and is therefore regarded as a marine species, but it could also survive and mature in freshwater medium. We propose the establishment of a new family Piliniaceae for Pilinia and place it in Ishigeales. Molecular and morphological analysis of the culture strains, SAG 124.79 and SAG 2381, identified as the euryhaline alga Porterinema fluviatile, indicated that SAG 124.79 is in fact P. rimosa. However, SAG 2381 is true P. fluviatile, also displaying the characteristic plurilocular zoidangia. Porterinema was shown to be a member of the Chordariaceae, Ectocarpales sensu lato.

摘要

基于叶绿体atp B、psa A、psb A、psb C 和rbc L 基因的串联序列的分子系统发育表明，丝状褐藻Pilinia rimosa在系统发育上远离外果皮目，它已被分类（如Waerniella lucifuga）。在树中，Pilinia是由高统计值支持的由Ishige和Petroderma (Ishigeales)组成的进化枝的姐妹。unialgal P. rimosa的观察起源于黑尔戈兰（德国）、英格兰（英国）、伍兹霍尔（美国）和纽芬兰（加拿大）的文化显示出直接类型的生活史，通过典型的单房 zoidangia 繁殖，通常仅形成四个 zoid。尽管在 Kuckuck 的描述以及后来的出版物中描述了多眼zoidangia，但我们得出结论，这些观察结果是基于对串联形成的非常小的单眼zoidangia 的误解，通常在zoidangia 之间具有纵向壁。Pilinia rimosa生于岩石的洞穴或缝隙中，也生长在潮间带和喷淋带较深的墙壁或木桩上，因此被视为海洋物种，但它也可以在淡水介质中生存和成熟。我们建议建立一个新的蕨科Pilinia并将其放置在 Ishigeales 中。培养菌株 SAG 124.79 和 SAG 2381 的分子和形态学分析被鉴定为广盐藻Porterinema fluviatile，表明 SAG 124.79 实际上是P. rimosa。然而，SAG 2381 是真正的P. fluviatile，也显示出特征性的多眼 zoidangia。Porterinema被证明是 Chordariaceae Ectocarpales sensu lato的成员。