(Patrick) Potapova 2011 Category: Symmetrical biraphid
BASIONYM: Navicula pennsylvanica Patrick 1966
SYNONYM(S): Navicula concava Patrick
REPORTED AS: Achnanthes imperfecta (Schimanski 1978, pl. I: figs. 1-5) | Nupela imperfecta (Lange-Bertalot and Genkal 1999, pg.80)
Contributor: Marina Potapova - October 2010
Length Range: 14-27 µm
Width Range: 4.9-5.9 µm
Striae in 10 µm: 26-30
Valves are linear-lanceolate with parallel or slightly constricted margins n the middle portion of the valve. Ends subrostrate. Striae are slightly radiate throughout the valve, parallel or slightly convergent at the apices, 26-30 in 10 μm. The raphe is absent on one of the valves, but the raphe slit is incompletely filled by silica and visible. Both valves have a lanceolate axial area, which on the rapheless valve is covered by reticulate siliceous thickenings. The central area on the rapheless valve is continuous with the axial area and sometimes is expanded to the margin on one side of the valve. The central area on raphe valve is circular and sometimes expanded to the valve margin on one or both sides. The raphe is almost straight; externally it lies in a shallow furrow. External proximal raphe ends are simple or slightly expanded. Internal proximal raphe slits are T-shaped.
Basionym: Navicula pennsylvanica
Author: Patrick 1966
Length Range: 20-23 µm
Width Range: 4-5 µm
Striae in 10 µm: 26-29
Valve linear, concave in the middle portion; ends rostrate. Axial area broad, widening toward the center of the valve. Median ends of the raphe fairly distant from each other. Central area large, rounded. Striae radiate at the center of the valve, parallel or only slightly radiate at the ends. Frustules not in filaments. Striae, 26-29 in 10μ. Length, 20-23μ. Breadth at the central nodule, 4-5μ.
Original text and images reproduced with permission by Academy of Natural Sciences of Philadelphia.
Lange-Bertalot, H. and Genkal, S.I. (1999). Diatoms from Siberia I. Islands in the Arctic Ocean (Yugorsky-Shar Strait). Iconographia Diatomologica 6: 1-292.
Patrick, R.M. and Reimer, C.W. (1966). The Diatoms of the United States exclusive of Alaska and Hawaii, V. 1. Monographs of the Academy of Natural Sciences of Philadelphia 13.
Potapova, M. (2011). New species and combinations in the genus Nupela from the USA. Diatom Research. 10.1080/0269249X.2011.575111
Schimanski, H. (1978). Beitrag zur Diatomeenflora des Frankenwaldes. Nova Hedwigia 30: 557-634.