Pelagophytes (Heterokonta) are a morphologically diverse class of marine algae historically united only by DNA sequences. We established clonal cultures of sand‐dwelling pelagophytes collected from intertidal pools around Australia. Phylogenetic trees based on nuclear 18S rDNA and plastid rbcL, psaA, psaB, psbA, and psbC sequences revealed two new genera, Gazia and Glomerochrysis, related to Aureoumbra in a distinct lineage within the Sarcinochrysidaceae (Pelagophyceae). The three new species (Gazia saundersii, Gazia australica, and Glomerochrysis psammophila), along with an Australian strain of Aureoumbra geitleri, are characterized by dominant benthic stages that differ significantly from one another, while occasionally producing classic heterokont zoospores. The benthic stage of Ga. saundersii has a novel development not observed in any other colonial alga, consisting of large, spherical colonies (up to 140 μm in diameter) containing c. 2,500 cells that eventually differentiate and segregate into a large number of daughter colonies that are subsequently liberated. Alternatively, colonies may differentiate into a mass of zoospores that escape and settle to develop into new colonies. In Gl. psammophila, cubic packets of cells form large sticky clusters that bind sand together, while Ga. australica and A. geitleri are unicellular species. Using fixation by high‐pressure freezing, a distinctive perforated theca was observed by TEM in all genera of this lineage, and we hypothesize this unique covering may be the first morphological feature to characterize most, if not all, pelagophytes. This study substantiates the diverse nature of sand‐dwelling pelagophytes as well as their mechanisms for thriving in a dynamic habitat.

中文翻译：

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新的pelagophytes显示了藻类菌落发展的一种新模式，并揭示了可能定义该类的穿孔的卵泡膜

Pelagophytes（Heterokonta）是一类形态多样的海藻，过去仅通过DNA序列结合在一起。我们建立了从澳大利亚各地潮间带池中收集的沙生植物的克隆培养物。基于核18S rDNA和质体rbc L，psa A，psa B，psb A和psb C序列的系统发生树揭示了两个新属Gazia和Glomerochrysis，与金黄色葡萄球菌属在金藻科（Selcinochrysidaceae（Pelagophyceae））内的不同谱系有关。这三个新物种（Gazia saundersii，Gazia australica和Glomerochrysis psammophila（）和澳大利亚的Aureoumbra geitleri菌株的特征是优势底栖动物阶段，彼此之间显着不同，但偶尔会产生经典的异动孔游动孢子。中华绒螯蟹的底栖阶段具有在任何其他殖民藻中均未观察到的新颖发育，其由含有c的大型球形菌落（直径最大为140μm）组成。2500个细胞最终分化并分离为大量子集，随后被释放。或者，菌落可以分化成大量的游动孢子，它们逃逸并沉降以发展成新的菌落。在Gl中。嗜肺菌，细胞的立方小包形成了大的粘性簇，将沙子粘合在一起，而澳洲草和吉特勒是单细胞物种。通过高压冷冻进行固定，通过TEM在该谱系的所有属中观察到了一个独特的穿孔卵泡膜，我们推测这种独特的覆盖物可能是表征大多数（如果不是全部）象牙兰的首个形态特征。这项研究证实了沙生植物的多样性，以及它们在动态栖息地中繁衍的机制。