Phryganella acropodia Hertwig and Lesser, 1874, is one of the most common and abundant testate amoeba species. It represents the type species of the genus Phryganella Penard, 1902, which in turn is the type genus for the suborder Phryganellina (Arcellinida) Bovee, 1985, but despite its taxonomic importance it was not yet analyzed with molecular methods. We established two cultures of putative Phryganella acropodia, designed Phryganellina-specific primers, amplified SSU rDNA data and subjected these sequences to phylogenetic analyses. Morphological and genetic differences were found between both strains. With SSU rDNA phylogenetic analyses we confirm that Phryganella acropodia branches with Phryganella paradoxa Penard, 1902 and Cryptodifflugia Penard, 1890 in the Phryganellina. We thus give further evidence that pseudopodia morphology in the Arcellinida is a character of high taxonomic value, as suggested by Bovee and Jung when erecting the suborder Phryganellina. Moreover, we provide evidence for cryptic diversity and for the first time confirm the existence of a naked life stage in Arcellinida by molecular means.

Phryganella acropodia Hertwig and Lesser，1874年，是最常见和丰富的睾丸变形虫之一。它代表1902年Phryganella Penard属的类型种，而Phryganella Penard属1985年Phryganellina（Arcellinida）Bovee亚种的类型属，但是尽管它在分类学上很重要，但尚未使用分子方法进行分析。我们建立了推定的拟南芥（Phryganella acropodia）的两种培养物，设计了Phryganellina特异的引物，扩增了SSU rDNA数据，并对这些序列进行了系统发育分析。在两个菌株之间发现形态和遗传差异。通过SSU rDNA的系统发育分析，我们确认了Phryganella acropodia分支与Phryganella paradoxa彭纳德（Penard）（1902年）和隐隐窝（Cryptodifflugia Penard），1890年在Phryganellina。因此，我们提供了进一步的证据，正如Bovee和Jung在架设Phryganellina时所建议的那样，Arcellinida中的伪足形态具有很高的分类学价值。此外，我们提供了隐秘多样性的证据，并首次通过分子手段证实了Arcellinida中存在裸露的生命阶段。