Lithophyllum okamurae is one of the important encrusting coralline algae, which plays important roles as primary producer, carbonate sediment builder, and habitat provider in the marine ecosystems. In this study, L. okamurae was collected from tropical coast of Sanya, and firstly described based on both detailed morph-anatomical characteristics and molecular studies of typic DNA sequences. The structure of the thalli of L. okamurae was pseudoparenchymatous construction with radially organized dimerous organizations in the crustose portion. The pseudoparenchymatous construction were composed of three parts, including 1 to 3 layers of epithelia cells which had flatten to round outermost walls, one layer of square or rectangular cells of the hypothallia and multiple layers of square or elongated rectangular peripheral cells. Palisade cells were observed, and the cells of the contiguous vegetative filaments were connected by secondary pit-connections with cell fusions absent. The carposporangial conceptacles, the spermatangial conceptacles, the bisporangial conceptacles and the tetrasporangial conceptacles were observed, and all these four kinds of conceptacles were uniporate. The spermatangial conceptacles were slightly convex and buried at shallow depths in the thalli tissues, and the carposporangial conceptacles and asexual conceptacles were protruding and conical. Phylogenetic studies based on DNA barcoding markers of 18S rDNA, COI, rbcL and psbA revealed that L. okamurae clustered with the closest relation of L. atlanticum, and formed a distinct branch. Based on the comparative anatomical features and the molecular data, the detailed description of the valid species of L. okamurae was firstly given in this study to provide theoretical basis for algae resources utilization and conservation in marine ecosystems.

中文翻译：

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海洋生态系统中分布广泛的甲壳珊瑚藻类-Lithophyllum okamurae（Lithophylloideae，Corallinales）的详细描述

冈村石藻是重要的包埋珊瑚藻类之一，在海洋生态系统中作为主要生产者，碳酸盐沉积物建造者和栖息地提供者发挥着重要作用。在这项研究中，冈村乳杆菌是从三亚热带海岸收集的，首先基于详细的形态解剖特征和典型DNA序列的分子研究进行了描述。的菌体结构L. okamurae是假性薄壁组织，在rust壳部分有放射状组织的二元组织。假性实质结构由三部分组成，包括1-3层上皮细胞，这些上皮细胞具有扁平至圆形的最外壁，下丘脑的一层正方形或矩形细胞，以及多层正方形或细长的矩形外周细胞。观察到栅栏细胞，并且相邻的营养丝的细胞通过次级凹坑连接而没有细胞融合。观察到了鼻孔囊，精囊孔，双孔囊和四孔囊，这四种孔都是单孔的。精原细胞的概念触角略微凸出，并埋在浅层的海藻组织中，房孔小囊和无性小囊突出且呈圆锥形。基于18S rDNA，COI，rbcL和DNA的DNA条形码标记的系统发育研究psbA显示，冈村乳杆菌与大西洋乳杆菌的亲缘关系最紧密，并形成一个独特的分支。基于比较的解剖特征和分子数据，本研究首先对冈村乳杆菌的有效种类进行了详细描述，为海洋生态系统中藻类资源的利用和保护提供理论依据。