A taxonomic appraisal on the rare green algal genus Ecballocystopsis M.O.P.Iyengar (Chlorellales: Trebouxiophyceae): morphological and numerical approach

Ecballocystopsis (Oocystaceae, Chlorellales, Trebouxiophyceae) is a rare green algal genus, represented by only five taxa including E. dichotoma from China and the other four taxa, i.e. E. indica, E. desikacharyi, E. himalayensis and E. dichotoma var. minuta from India. The present communication proposes a novel variety E. dichotoma var. anandii from Jharkhand; synonymization of E. himalayensis with E. dichotoma and erection of E. dichotoma var. minuta to a separate species E. minuta stat. et comb. nov. These taxonomic changes were well supported by the results of multivariate analysis based on numerical taxonomic approach. Cluster Analysis (CA), Principal Component Analysis (PCA) and Principal Coordinates Analysis (PCoA) were performed to resolve the species delimitation ambiguity and supplement the morphology based classification of the genus. E. himalayensis and E. dichotoma grouped in a single cluster along with the proposed new variety, while E. indica, E. desikacharyi and E. minuta into separate clusters. A species identification key to the genus Ecballocystopsis is also presented.

喷囊藻属（Ecballocystopsis）隶属于卵囊藻科（Oocystaceae）、小球藻目（Chlorellales）、共球藻纲（Trebouxiophyceae），是一类较为罕见的绿藻属，目前仅记载有5个分类单元：其中包括产自中国的二叉喷囊藻（E. dichotoma），以及4个产自印度的分类单元，即印度喷囊藻（E. indica）、德氏喷囊藻（E. desikacharyi）、喜马拉雅喷囊藻（E. himalayensis）和微缩小二叉喷囊藻（E. dichotoma var. minuta）。本研究报道了1个采自贾坎德邦的新变种——安纳德二叉喷囊藻（E. dichotoma var. anandii）；同时提出将喜马拉雅喷囊藻（E. himalayensis）归为二叉喷囊藻（E. dichotoma）的同物异名，并将微缩小二叉喷囊藻（E. dichotoma var. minuta）提升为独立物种微缩喷囊藻（E. minuta，stat. et comb. nov.）。上述分类学修订均得到基于数量分类学方法的多变量分析结果的有力支持。本研究通过聚类分析（Cluster Analysis, CA）、主成分分析（Principal Component Analysis, PCA）及主坐标分析（Principal Coordinates Analysis, PCoA），以厘清该属物种界定的模糊性，并完善基于形态学的该属分类系统。聚类结果显示，喜马拉雅喷囊藻（E. himalayensis）、二叉喷囊藻（E. dichotoma）与本次提出的新变种聚为单一簇群，而印度喷囊藻（E. indica）、德氏喷囊藻（E. desikacharyi）及微缩喷囊藻（E. minuta）则各自形成独立簇群。本研究同时提供了喷囊藻属（Ecballocystopsis）的物种鉴定检索表。