Nupela marvanii sp. nov., and N. lapidosa (KRASSKE) LANGE-BERTALOT in Poland with notes on the distribution and ecology of the genus Nupela (Bacillariophyta).

Abstract

Two species of Nupela were identified in a spring and in a small spring-fed pool in the Polish Tatra Mts, - these were N. lapidosa and Nupela sp. The second species is described as N. marvanii. The new species is characterized by heteropolar, narrowly elliptic valves with capitate apices. Sternum valve has very short, sometimes rudimental raphe branches. Under a light microscope transapical striae are not discernible. Externally both valves are covered with hymen. The central area of sternum valves has irregular silicate thickenings. Proximal raphe fissures are straight and terminate in small pores. Distal raphe fissures double-deflected into the same side of the valve, form ?-shaped structures that extend onto the mantle. Internally visible linear-lanceolate axial area, which forms unilateral fascia on raphe valve, which reaches valve margin. Proximal raphe fissures are T-shaped. Distal raphe fissures are straight, and terminate in small, linear helictoglossa. Sternum valve has large, clearly visible internally, asymmetrically lanceolate central area and discernible externally reinforced median costa. Raphe fissures are strongly reduced, rudimental. The areole are round to elliptical, expanded along the transapical axis, with the wider opening on the external surface. An irregular row of similar areoles is present along pleural side of valve. Both species are documented with LM and SEM micrographs and briefly discussed. The distribution and autecology of 46 Nupela members are summarized.