中文摘要：

报道分别从湖北省武汉市内和云南省西双版纳小水池中分离培养的两株绿藻，对其进行了形态和18S rDNA基因序列分析，编号分别为FACHB-1783和FACHB-1784。这两株绿藻具独特的四边形群体形态，通常为4或16个细胞，细胞为宽椭圆形至不规则卵圆形、细胞壁两端无增厚，叶绿体多数、片状，具蛋白核。结合形态和分子系统发育分析，确定这两株绿藻为我国1 种淡水共球藻纲新记录属种——土佐牧野藻(Makinoella tosaensis Okada)。基于18S rDNA基因的系统发育研究表明这两株绿藻与分离自韩国的土佐牧野藻基因序列相似度可达99.6%~99.9%，并且以较高的支持值与土佐牧野藻聚在一起。

英文摘要：

Two strains of green algae with No. FACHB-1783 and FACHB-1784 were isolated from small ponds inWuhan, Hubei Province and Xishuangbanna, Yunnan Province, respectively. Their morphology and 18S rDNAsequences were studied. The typical coenobia of two strains are tetragonally arranged in flat, usually 4–16-celled.Cells are broad ellipsoid to irregularly oval, without polar thickenings. Numerous chloroplasts are discoid, eachwith a pyrenoid. Based on morphological and molecular phylogenetic evidences, the two strains were identified asMakinoella tosaensis Okada, which was considered as a new recorded genus and species of freshwatertrebouxiophycean algae from China. The 18S rDNA sequence of the strains showed high similarity (99.6%-99.9%)with those of M. tosaensis Okada from Korea. The phylogenetic analyses based on 18S rDNA sequence showedthat all strains of M. tosaensis Okada clustered into a clade with high support values.