Morphology and molecular phylogeny of Aureophycus aleuticus gen. et sp nov (Laminariales, Phaeophyceae) from the Aleutian Islands
Morphology and molecular phylogeny of Aureophycus aleuticus gen. et sp nov (Laminariales, Phaeophyceae) from the Aleutian Islands
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DOI：
10.1111/j.1529-8817.2008.00548.x
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发表时间：
2008-08-01
影响因子：
2.9
通讯作者：
Lindstrom, Sandra C.
中科院分区：
文献类型：
--
作者：
Kawai, Hiroshi;Hanyuda, Takeaki;Lindstrom, Sandra C.
在阿留申群岛的卡加米尔岛上发现了一种以前未知的海带。该种与已知的海带类植物区别很明显：孢子体直立，叶片薄，披针形，高约2 m，宽约0.50 m，无中脉，过渡带边缘加厚，呈V形，柄实心，扁平，稍半透明，长约1 m;固着器为半盘状，直径可达0.15 m。在解剖学上，叶片具有典型的喇叭形菌丝特征，是脊索科和衍生的叶状海带目物种（即，Alariaceae/Laminariaceae/Lessoniaceae）。叶片和柄上无毛坑或粘液结构。没有收集到可育孢子体，但在田间观察到丰富的幼年孢子体。利用叶绿体rbcL基因、核ITS 1 -5. 8 S-ITS 2 rDNA和线粒体nad 6 DNA序列进行分子系统学分析，将一新种（Aureophycus aleuticus gen. et sp. nov.）与传统分类学的Alariaceae或Lane et al.（2006）的“Group 1”分支（包括Alaria和相关类群）相比，与其他类群的关系更密切，尽管该物种没有明确地包括在该组中。Aureophycus可能是阐明海带目中Alariaceae进化的关键种。由于缺乏生殖器官的信息和分子分析的分辨率不足，我们没有将新种分配到一个科，但我们将新种放在海带目的一个新属中。
A previously unknown species of kelp was collected on Kagamil Island, Aleutian Islands. The species can be easily distinguished from any known laminarialean alga: the erect sporophytic thallus is composed of a thin lanceolate blade attaining similar to 2 m in height and similar to 0.50 m in width, without midrib, and the edge of the blade at the transition zone is thickened to form a V-shape; the stipe is solid and flattened, slightly translucent, attaining similar to 1 m in length; the holdfast is semidiscoidal and up to 0.15 m in diameter. Anatomically, the blade has the typical trumpet-shaped hyphae characteristic of the Chordaceae and derived foliose laminarialean species (i.e., Alariaceae/Laminariaceae/Lessoniaceae). No hair pits or mucilaginous structures were observed on the blade or stipe. No fertile sporophytes were collected, but abundant juvenile sporophytes were observed in the field. In the molecular phylogenetic analyses using chloroplast rbcL gene, nuclear ITS1-5.8S-ITS2 rDNA, and mitochondria nad6 DNA sequences, the new species (Aureophycus aleuticus gen. et sp. nov.) showed a closer relationship with Alariaceae of conventional taxonomy, or the "Group 1" clade of Lane et al. (2006) including Alaria and related taxa than with other groups, although the species was not clearly included in the group. Aureophycus may be a key species in elucidating the evolution of the Alariaceae within the Laminariales. Because of the lack of information on reproductive organs and insufficient resolution of the molecular analyses, we refrain from assigning the new species to a family, but we place the new species in a new genus in the Laminariales.