ABSTRACT The phylogroup Chloromonadinia (Volvocales, Chlorophyceae) encompasses ecologically versatile green microalgae with a predominantly freshwater and snow lifestyle. Although a few species have been described from soils, the evolutionary history of terrestrial volvocalean flagellates is poorly known due to undersampling. Here we provide new insights into the phylogenetic position of terrestrial flagellates within the Chloromonadinia and investigate six unresolved strains from terrestrial and freshwater habitats in both hemispheres. The terrestrial strains differed in cell morphology, ultrastructure and lifestyle from the freshwater ones, therefore, we expected them to represent distinct evolutionary lineages (species or genera). While the terrestrial strain SAG 25.87 (Chloromonas gracillima comb. & stat. nov.) from Czech mountains clustered within the psychrotolerant core Chloromonas clade, the other terrestrial strains formed a phylogenetically separate lineage which we proposed as Ostravamonas gen. nov. The new genus differs from other closely related Chloromonadinia genera by chloroplast, eyespot, papilla and cell-wall morphology. Two terrestrial strains, CAUP G 1401 (coal spoil heap; Czechia) and SAG 12.72 (acidic soil; New Zealand), were designated as Ostravamonas chlorostellata comb. nov. and represent the first Chloromonadinia microalgae discovered in acidic terrestrial environments. Closely related ‘Chlamydomonas’ strains SAG 75.81 (ditch; France) and CCAP 11/108 (origin unknown) were reassigned to Ostravamonas meslinii comb. nov. and Ostravamonas tenuiincisa sp. nov., respectively. Our study shows that the traditional ‘Chlamydomonas’ still hides an overlooked diversity of species with a terrestrial lifestyle that are nested phylogenetically within the Chloromonadinia phylogroup.

中文翻译：

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在主要的淡水和雪系统群 Chloromonadinia (Volvocales, Chlorophyceae) 中被忽视的陆地生活方式多样性

摘要 Chloromonadinia (Volvocales, Chlorophyceae) 包括生态多功能的绿色微藻，主要以淡水和雪地为生。尽管已经从土壤中描述了一些物种，但由于采样不足，对陆生涡尾鞭毛虫的进化历史知之甚少。在这里，我们提供了对 Chloromonadinia 中陆地鞭毛虫系统发育位置的新见解，并调查了来自两个半球陆地和淡水栖息地的六种未解决的菌株。陆生菌株在细胞形态、超微结构和生活方式方面与淡水菌株不同，因此，我们预计它们代表不同的进化谱系（种或属）。而陆生菌株 SAG 25.87 (Chloromonas gracillima comb. & stat. nov. ）来自聚集在耐冷核心绿单胞菌进化枝内的捷克山脉，其他陆生菌株形成了一个系统发育分离的谱系，我们将其提议为 Ostravamonas gen。十一月 这个新属在叶绿体、眼点、乳头和细胞壁形态方面与其他密切相关的 Chloromonadinia 属不同。两种陆生菌株 CAUP G 1401（煤渣堆；捷克）和 SAG 12.72（酸性土壤；新西兰）被指定为 Ostravamonas chlorostellata comb。十一月 并代表了在酸性陆地环境中发现的第一个 Chloromonadinia 微藻。密切相关的“衣藻”菌株 SAG 75.81（沟渠；法国）和 CCAP 11/108（来源不明）被重新分配给 Ostravamonas meslinii 梳。十一月 和 Ostravamonas tenuiincisa sp。十一月，分别。