The testate amoeba Leptogromia operculata was described by Valkanov in 1970 from marine waters. We re-discovered this species in brackish water along the North Sea in the Netherlands. Based on detailed comparison of morphology and SSU rDNA phylogeny we conclude that this species represents a sister clade to the Euglyphida (Imbricatea, Cercozoa). We further describe a similar species Trivalvularis immunda gen. nov., sp. nov. from freshwater in France and the Netherlands on basis of morphological data. Trivalvularis and Leptogromia share a unique oral apparatus with three valves that can close the aperture of the shell. Due to this unique morphological character and the phylogenetic analysis of L. operculata we place both species in a new family Trivalvulariidae in the new order Trivalvulariida.

Valkanov于1970年从海水中描述了睾丸变形虫Leptogromia operculata。我们在荷兰北海的微咸水中重新发现了该物种。根据形态和SSU rDNA系统发育的详细比较，我们得出结论，该物种代表了Euglyphida（Imbricatea，Cercozoa）的姐妹进化枝。我们进一步描述了类似物种Trivalvularis immunda gen。十一月，sp。十一月 根据形态数据从法国和荷兰的淡水中提取。Trivalvularis和Leptogromia共享一个独特的口腔器械，其三个阀门可以关闭外壳的孔。由于这种独特的形态学特征和小木的系统发育分析 我们将两个物种按照新的Trivalvulariida顺序放入新的Trivalvulariidae科。