Two strains of Sphaerodinium were established from two mountain areas in Portugal and examined by light microscopy, scanning and transmission electron microscopy, and sequence analyses of nuclear-encoded SSU, ITS1–5.8S–ITS2 and LSU rDNA. Both strains were identified as S. polonicum var. tatricum on the basis of comparison with the original taxonomic descriptions within the genus. The two strains were nearly identical in morphology and ultrastructure, except for the presence of pseudograna-like thylakoid stacks within more rounded chloroplast lobes in one of them. Sexual reproduction occurred in culture batches and resting cysts with single or grouped processes with wide bases and distal platforms with slightly recurved margins were seen to develop by sudden retraction of planozygote cytoplasm. Morphological, fine-structural and molecular characters were compared with previously available information from S. cracoviense, allowing for a more robust characterization of the genus. Important characters include a type F eyespot, a pusule canal linking the transverse flagellar canal to a collecting chamber connected to regular pusular tubes, a ventral fibre extending from the proximal-right side of the longitudinal basal body, and a membranous, lamellar body with a honeycomb pattern near the flagellar base area. The latter two features are shared with Baldinia anauniensis.

在葡萄牙的两个山区建立了两个球形球菌菌株，并通过光学显微镜，扫描和透射电子显微镜以及核编码的SSU，ITS1-5.8S-ITS2和LSU rDNA的序列分析进行了检查。两种菌株均被鉴定为S.polonicum var。ta在与属内原始分类学描述进行比较的基础上。两种菌株在形态和超微结构上几乎相同，除了其中之一更圆形的叶绿体裂片中存在假颗粒样类囊体堆叠。有性繁殖发生在培养物批次中，并且单个或成组的具有宽基部和远端平台，边缘稍弯曲的远端囊肿的静息囊肿被认为是由于扁平接合体细胞质的突然回缩而发展的。将形态学，精细结构和分子特性与S. cracoviense先前可获得的信息进行了比较，可以对属进行更可靠的表征。重要特征包括F型眼点，将横鞭毛管连接至与规则的脓疱管相连的收集室的脓疱管，从纵向基体近端右侧延伸的腹侧纤维，膜状层状体以及鞭毛基部附近有蜂窝状图案。后两个特征与Baldinia anauniensis共有。