Pseudocarteria corcontica, a new quadriflagellate species (Volvocales).

A new species Pseudocarteria corcontica is described from small, acidic and oligotrophic water bodies in the Krkonoše Mts (Czech Republic). The cells are 17–27 × 22–35 µm in size, ellipsoidal or obovate and with a low truncate papilla. The thick cell wall is sometimes separated from the protoplast at the posterior end of the cell. The chloroplast is indistinctly asteroid with an ellipsoidal or half-ellipsoidal pyrenoid located below the centre of the cell. Numerous contractile vacuoles are not scattered as in other Pseudocarteria species, but mostly concentrated in the upper third of the cell and form circle beneath the cell wall. A small elliptical stigma is located in the anterior part of the cell. Cells divide in immobile sporangia (up to 38 µm in diameter) producing 2 or 4 daughter cells. Sexual reproduction is isogamic.