Paramphitrema pontica Valkanov, 1970
In the publication on the protozoans of the Black Sea Valkanov (1970) described a new genus and species, named Paramphitrema pontica. It was found in the bottom sediments of a firth near Varna at a depth of one to three meters. As a result of the morphological description of the shell, the protoplasm, the pseudopodia and the movement of the animal, Valkanov considered this new species different from all other species of the related genus Amphitrema and created a new genus Paramphitrema. The basic characteristics of P. pontica are the presence of xenosomes on the proteinaceous shell and the existence of two short tubes at the two poles of the shell. The apertures of the shell are at the distal ends of the tubes. According to Valkanov (1970) the freshwater species Amphitrema rhenanum Lauterborn, 1886, and A. lemanense Penard, 1902, whose shells are covered with xenosomes and whose apertures are also disposed at the ends of the brief proteinaceous tubes, must be transferred to the new genus. An important morphological feature of P. pontica is the presence of long distal tubes of the shell with a funnel-like enlargement around the apertures. P. pontica emits only one non-branched pseudopodium that helps the animal.