Plagiopyla, STEIN, 1860

GENUS PLAGIOPYLA STEIN, 1860 View in CoL View at ENA

Improved diagnosis: Ovoid body shape, dorso-ventrally compressed; slit-like buccal aperture; deep oral cavity, with tubular part usually extending to left ( Fig. 17A), or curving anteriorly, then posteriorly ( P. mystax ) ( Fig. 17B); uniform, dense somatic ciliature; striated band on dorsal surface, arising near right margin of oral cavity; cytoproct suture opening on dorsal side; usually single contractile vacuole with pores (usually two) opening on dorsal surface; one macronucleus (or two in the case of P. binucleata ); one compact-type micronucleus in most species (more than one in P. ramani and P. stenostoma ); extrusomes (straight and/or curved) inserted in body cortex.

Type species: Plagiopyla nasuta Stein, 1860 , by monotypy.

Stein (1860) describes P. nasuta as a ciliate with the body size almost equal to that of Pleuronema chrysalis (namely about 70–120 µm in length), found in the swamp waters near Prague and Niemegk. It has a dense cortical layer, crossed by tactile corpuscles (presumably the striated band). The oral slit is located in the centre of the body, extending from the right side to the longitudinal axis. At the end of oral slit, Stein describes ‘a very small pharynx that leads to the oral opening’. The author points out that the cilia in the dorsal part of the body are missing (!). The ovoid nucleus is located on the right side of the body behind the peristome. The contractile vacuole is located at the body end.