A new level of confidence: biogeography, morphometry and ecology of enigmatic Cyclopyxis puteus Thomas, 1960 (Amoebozoa: Arcellinida: Netzeliidae)

Testate amoebae Cyclopyxis puteus Thomas (1960) has a characteristic morphology, that makes the possibility of overlook or misidentification unlikely. Although this species has been found worldwide, its morphology, biometrics and ecological preferences are poorly understood. In this study, isolated material from Bulgaria was investigated by using light and scanning electron microscopy. Based on morphological and biometrical data, we provide an improved diagnosis of this enigmatic species. A summary of the geographical distribution and ecological preferences is provided.