A revision of the tribe Chondrieae (Ceramiales, Rhodophyta) from the Russian Pacific coast with descriptions of two new species (Chondria pendula sp. nov. and C. epiphytica sp. nov.) and the genus Nothochondria dimorphica gen. et sp. nov

Until recently, two species of the tribe Chondrieae were recorded from the Russian Pacific coast: Chondria dasyphylla and C. decipiens. In this study we re-examined these algae from the region using comparative morphological and molecular analyses. It was shown that both C. dasyphylla and C. decipiens do not occur in the studied region. Specimens previously identified as ‘C. decipiens’ are confirmed as Neochondria ammophila based on molecular and morphological analyses. Specimens from the Russian Pacific coast previously identified as C. ‘dasyphylla’, represent a complex of species, described here as a new genus Nothochondria, with N. dimorphica sp. nov., and two new species, C. epiphytica and C. pendula. Phylogenetic analysis based on COI, rbcL and SSU indicates that N. dimorphica forms a strongly supported clade separate from a diverse clade containing Chondria capillaris, the generitype of Chondria, as well as from the recently described genus, Neochondria. Based on its vegetative anatomy, Nothochondria is intermediate between Chondria and Neochondria. Similarly to Neochondria, it has adventitious cells among pericentral cells, while the distinctness of the axial and pericentral cells throughout the thallus makes it close to Chondria. Data on the distribution of these species along the Russian Pacific coast are provided. There is no evidence that Chondria dasyphylla and C. decipiens that had been reported from the Russian Pacific coast occur here.A new genus Nothochondria and two new species of Chondria, Chondria epiphytica and C. pendula, are proposed.The new taxa are distributed from the southern Sea of Japan to the southern Sea of Okhotsk. There is no evidence that Chondria dasyphylla and C. decipiens that had been reported from the Russian Pacific coast occur here. A new genus Nothochondria and two new species of Chondria, Chondria epiphytica and C. pendula, are proposed. The new taxa are distributed from the southern Sea of Japan to the southern Sea of Okhotsk.直至近期，俄罗斯太平洋沿岸曾记录有软骨藻族（Chondrieae）的2个物种：软骨藻属（Chondria）的Chondria dasyphylla与C. decipiens。本研究采用比较形态学与分子分析方法，重新检视了该区域的上述藻类。研究结果显示，这两个物种均未在本次研究区域中出现。此前被鉴定为‘C. decipiens’的标本，经分子与形态分析确认实为新软骨藻属（Neochondria）的Neochondria ammophila。此前在俄罗斯太平洋沿岸被鉴定为‘C. dasyphylla’的标本，实则为一个物种复合体，本文将其描述为新属拟软骨藻属（Nothochondria），该属包含N. dimorphica sp. nov.以及另外两个新种：C. epiphytica与C. pendula。基于COI、rbcL及SSU序列的系统发育分析表明，N. dimorphica形成了一个强支持的单系演化支，该演化支独立于包含软骨藻属模式种Chondria capillaris的多样演化支，同时也独立于近年新建立的新软骨藻属（Neochondria）。从营养解剖结构来看，拟软骨藻属（Nothochondria）介于软骨藻属（Chondria）与新软骨藻属（Neochondria）之间：与新软骨藻属类似，其围轴细胞间存在不定细胞；而整个叶状体的轴细胞与围轴细胞分界清晰，这一特征又使其接近软骨藻属。本文提供了这些物种在俄罗斯太平洋沿岸的分布数据。此前报道产自俄罗斯太平洋沿岸的Chondria dasyphylla与C. decipiens，实际上并不分布于此。本文提议建立新属拟软骨藻属（Nothochondria）以及软骨藻属（Chondria）的两个新种：Chondria epiphytica与C. pendula。上述新类群的分布范围从日本海南部延伸至鄂霍次克海南部。