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Diatoms of the Southern California Bight
Genus Navicula Information from California Academy of Sciences Catalogue of Diatom Names
Genus Navicula Description from Diatoms of the United States http://dbmuseblade.colorado.edu/DiatomTwo/dscb_site/genus.php?g=Navicula
Navicula angusta Grunow 1860
Description:
Valves linear, with margins straight and parallel to slightly convex, and apices protracted and broadly rounded. Length 30-70 µm, breadth 5-8 µm. Axial area very narrow, forming a circular to elliptical (sometimes asymmetrical) central area. Raphe lateral, external proximal ends dilated and bent slightly to one side. Distal raphe ends terminate in an unornamented area. Striae radiate, becoming parallel then convergent at the poles, 11-12/10 µm.
Navicula arenaria Donkin 1861
Description:
Valves lanceolate to linear, tapering to subacute apices. Valves arched, so that striae in focus in the center of the valve appear out of focus or interrupted near the margins. Length 30-80 µm, breadth 8-11 µm. Axial area narrow, broadening laterally at the center to form a rectangular central area. Raphe straight, with dilated external proximal raphe ends terminating close to one another. Striae around the center more coarse than the rest of the valve. Striae radiate around the center, becoming parallel or even convergent at the apices. Striae number 9-10/10 µm.
Navicula arvensis Hustedt 1937
Description:
Valves linear-elliptical with apices barely produced. Length 5-15 µm, breadth 2.5-4.0 µm. Raphe filiform, within a very narrow axial area. Central area small, indistinct. Striae not visible with light microscopy.
Navicula brasiliana (Cleve) Cleve
Description:
Valves lanceolate to elliptical-lanceolate in smaller specimens, apices rounded. Length 20-55 µm, breadth 9-16 µm. Axial area straight, widening towards the center to form a linear-elliptical central area bordered by striae that are more coarse in this density and have shorter striae interspersed between them. Raphe is lateral, undulate, with external proximal ends prominent. External distal raphe ends are hooked in the same direction. Punctate striae are strongly radiate for most of the length of the valve, becoming strongly convergent towards the poles, the shift in orientation is dramatic. Striae number 18-22/10 µm.
Navicula capitatoradiata Germain 1981
Description:
Valves lanceolate with apices protracted, small, capitate. Length 25-45 µm, breadth 7-10 µm. Raphe filiform, straight, with proximal raphe ends dilated slightly. Axial area narrow, broadening to create a small, linear-lanceolate central area, formed 3-4 shortened striae on either side. Striae radiate in the center, becoming parallel towards the ends, and convergent near the poles, 11-15/10 µm.
Navicula cari Ehrenberg 1836
Description:
Valves linear to linear-lanceolate, tapered to rounded, not protracted, apices. Length 25-75 µm, breadth 6-11. Raphe filiform to slightly lateral, straight, with external proximal ends dilated and curved slightly to one side. Axial area narrow, broadening to form a linear-oblong central area. Striae in the middle portion of the valve arched and strongly radiate, becoming parallel to almost convergent at the apices. Lineolate striae number 9-16/10 µm.
Navicula cf. cari Ehrenberg 1836 SCCWRP BSL
Description:
Valves linear-lanceolate, apices not protracted, rounded. Length 26-40 µm, breadth 4-5 µm. Axial area narrow, straight, expanded to form a broadly rounded central area. Central area bordered by 2-4 shortened striae on either side of the central area. Raphe filiform, straight, with external proximal raphe ends dilated, straight. Distal raphe ends hooked in the same direction. Striae lineolate, strongly radiate in the center of the valve, becoming convergent at the apices. Striae number 12-13 /10 µm.
Navicula cf. menisculus Schumann 1867 SCCWRP MCB
Description:
Valves broadly lanceolate, with apices rouinded, not protracted. Length 15-20 µm, breadth 5-7 µm. Axial area narrow, straight, forming a small, irregularly shaped central area. Raphe filiform, straight, with external proximal ends dilated. Striae around the central area shortened, arched and more or less radiate, becoming radiate to convergent at the ends. Striae are lineolate, numbering 14-17/10 µm.
Navicula cf. protracta (Grunow in Cleve & Grunow) Cleve 1894 SCCWRP BSL
Description:
Valves linear-lanceolate, with apices slightly protracted and broadly rounded. Length 25 µm, breadth 6 µm. Axial area straight, broadening towards the middle to form a lanceolate central area. The raphe is filiform, straight, with external proximal ends dilated slightly. Striae around the center more coarse than other part of the valve. Striae are punctate, radiate about the center, becoming parallel just at the end of the valve. Striae number 22-26/10 µm. Rare.
Navicula cf. viridula var. rostellata (Kützing) Cleve 1895 SCCWRP MCB
Description:
Valves lanceolate, with apices rounded. Length 27-45 µm, breadth 7-9. Axial area narrow at poles, becoming wider towards the elliptical to irregularly-shaped central area. Central area border by 2-4 shortened striae on either side. Raphe filiform, with proximal ends deflected towards the same direction. Distal ends hooked in the direction opposite the proximal ends. Striae lineolate, orientated radiately, becoming convergent at the poles. Striae number 14-16/10 µm. Rare in the region.
Navicula cincta (Ehrenberg) Ralfs in Pritchard 1861
Description:
Valves linear-lanceolate, with apices rounded, length 15-40 µm, breadth 5-8 µm. Axial area narrow, straight, central area irregular, transversely widened, formed by central striae being smaller and more separate than others. Striae lineate, radiate in the middle of the valve where they number 9-1/10 µm, abruptly becoming convergent at the ends, more dense, around 16-18/10 µm.
Navicula concentrica Carter & Bailey-Watts 1981
Description:
Valves lanceolate with narrowly rounded apices that are not protracted. Length 40-75 µm, breadth 9-12 µm. Raphe weakly lateral. Axial area narrow, internally a distinct sternum is evident. Central area small, lanceolate, appearing strongly asymmetrical. Striae lineolate, strongly radiate, about 8-11/10 µm.
Navicula cryptocephala Kützing 1844
Description:
Valves lanceolate, with distinctly protracted, nearly capitate apices. Length 20-40 µm, breadth 5-7 µm. Axial area narrow, broadening around the middle to form an irregularly elliptical to circular central area. Lineolate striae are radiate about most of the length of the valve, becoming parallel to nearly convergent at the apices. Striae number 16-19/10 µm.
Navicula cryptotenella Lange-Bertalot in Krammer & Lange-Bertalot 1985
Description:
Valves small, lanceolate to rhomic-lanceolate, with narrowly rounded apices, somewhat produced. Length 14-40 µm, breadth 5-7 µm. Raphe filiform to slightly lateral, proximal raphe ends distinctly dilated. Axial area narrow, straight. Central area small, irregular in shape. Striae shortened around the central area. Striae are radiate about the center of the valve, becoming parallel to slightly convergent at the apices. Striae number 14-16/10 µm.
Navicula cryptotenelloides Lange-Bertalot 1993
Description:
Valves lanceolate with narrowly rounded, not protracted apices. Length 9-18 µm, breadth 3.7-4.2 µm. Raphe filiform, with proximal raphe ends small. Axial area linear, narrow. Central area slightly transversely expanded, indistinct, and irregularly-shaped. Striae radiate, becoming nearly convergent at the poles, 16-18/10 µm.
Navicula eidrigiana Carter 1979
Description:
Valves lanceolate, with apices rounded. Length 20-60 µm, breadth 6-8 µm. Axial area straight, forming a wide, rectangular central area bordered by 2-3 striae that are more coarse in their density, asymmetrical with one side broader and having shorter striae than the other. Raphe weakly lateral, more or less straight, with external proximal ends dilated and rounded. External distal raphe ends hooked in the same direction. Striae distinctly lineolate, radiate about the center, becoming parallel to the apices. Striae number 10-13/10 µm.
Navicula erifuga Lange-Bertalot in Krammer & Lange-Bertalot 1985
Description:
Valves lanceolate with bluntly rounded apices, seldom with the apices protracted slightly. Length 25-35 µm, breadth 5-7 µm. Raphe filiform, with proximal ends deflected in the same direction and dilated, terminating on the asymmetrical central nodule. Axial area narrow, broadening to form a small, elliptical to circular, asymmetrical central area. Lineate striae are radiate around the central portion of the valve, become parallel, and convergent at the poles. Striae number 12-14/10 µm.
Navicula gregaria Donkin 1861
Description:
Valve lanceolate, with narrowly protracted to almost capitate apices. Length 15-35 µm, breadth 5-8 µm. Axial area very narrow, expanded a small amount to form a elliptical central area. Striae are parallel (rarely slightly radiate in the center) the length of the valve, weakly lineate, 16-23/10 µm.
Navicula hasta Pantocsek 1892
Description:
Valves lanceolate, apices narrowly rounded. Length 70 µm, breadth 18 µm. Axial area narrow, straight, broadening to form an X-shaped central area. Striae around the central area are thicker, and more coarsely arranged, than others. Raphe lateral, more or less straight, with external proximal ends rounded and external distal ends deflected in the same direction. Striae lineolate, strongly radiate, except at the ends where they are radiate to nearly parallel. Striae number 5-6/10 µm about the center, 9-12/10 µm elsewhere on the valve.
Navicula lanceolata (Agardh) Kützing 1844
Description:
Valves lanceolate, with apices not protracted, rounded. Length 28-40 µm, breadth 8-11 µm. Axial area narrow at the poles, expanded to form a distinct rounded to elliptical central area. Raphe filiform, with external distal ends dilated slightly and bent very slightly in one direction, the external distal ends distinctly hooked, bent in the direction opposite the proximal ends. Striae distinctly lineolate, radiate at the center becoming convergent towards the ends. Striae number 12-14/10 µm.
Navicula leptostriata Jørgensen 1948
Description:
Valves lanceolate to linear-lanceolate, with apices rounded. Length 35-39 µm, breadth 5-6 µm. Axial area linear, relatively narrow, expanded to form a circular central area. Raphe lateral, with external proximal raphe ends straight, dilated. Striae lineolate, radiate most of the length of the valve, becoming convergent at the apices. Striae number 15-18/10 µm.
Navicula libonensis Schoeman 1970
Description:
Valves lanceolate with apices broadly rounded though in some cases the apices may be protracted slightly. Length 25-40 µm, breadth 5.5-8.0 µm. Raphe is slightly undulate, lateral. Axial area narrow, straight, broadening to form a small, transversely expanded central area that is asymmetrical in appearance. Striae strongly radiate throughout most of the length of the valve, becoming parallel to convergent at the poles, 12-14/10 µm. Voigt faults are prominent.
Navicula longa (Gregory) Ralfs in Pritchard 1861
Description:
Valves linear-lanceolate with apices barely protracted, rounded. Length 39-50 µm, breadth 6-9 µm. Axial area wide at the terminus, narrow then forming an asymmetrical, rounded to elliptical central area. External proximal raphe ends deflected in the same direction, while distal ends are hooked in the direction opposite the central ends. Raphe filiform. Striae lineolate, radiate most of the length of the valve, becoming convergent at the apices. Striae number 12-13/10 µm.
Navicula margalithii Lange-Bertalot in Krammer & Lange-Bertalot 1985
Description:
Valves linear-lanceolate to linear, tapering to broadly rounded apices. Length 30-70 µm, breadth 8-10 µm. Raphe lateral, with proximal ends dilated slightly. Axial area narrow, broadening to form an asymmetrical, small, elliptical
to circular central area. Lineate striae in the middle of the valve radiate, becoming parallel towards the poles, 9-12/10 µm. Voigt faults distinct.
Navicula menisculus Schumann 1867
Description:
Valves broadly lanceolate, with slightly rounded apices. Length 15-50 µm, breadth 7.5-12.0 µm. Axial area narrow, forming a small, irregular central area, barely differentiated. Striae are finely punctate, radiate, numbering 8-12/10 µm.
Navicula meniscus Schumann 1867
Description:
Valves lanceolate, with apices weakly protracted, rounded. Length 27-40 µm, breadth 8-10 µm. Axial area narrow, straight. The central area is not well developed, asymmetrical and irregular in shape. Raphe filiform, with proximal ends dilated slightly. Striae slightly radiate, becoming convergent at the apices. Striae number 13-16/10 µm. Rare. This identification is tentative, as these specimens need additional work to decipher their systematic placement.
Navicula normaloides Cholnoky 1968
Description:
Valves linear-lanceolate, with apices rounded. Length 33-44 µm, breadth 6-9µm. Axial area narrow, expanded to an irregularly-shaped, somewhat rounded central area with striae more coarse around the center than elsewhere on the valve. Raphe filiform, with dilated, straight, external proximal ends and distinctly hooked distal ends. Striae lineolate, radiate, becoming parallel to convergent at the apices. Striae number 14-16/10 µm. Rare.
Navicula oblonga Østrup 1910
Description:
Valves linear to linear-lanceolate, with apices broadly rounded and not protracted. Length 70-220 µm, breadth 12-14 µm. Axial area relatively wide, straight, forming an expanded rectangular central area with 2-3 shortened, widely spaced striae on either side. Raphe mostly lateral, with external proximal ends rounded slightly. Striae radiate, 6-9/10 µm, lineolate.
Navicula oppugnata Hustedt 1945
Description:
Valves linear-lanceolate, with apices narrowly rounded. Length 28-40 µm, breadth 6-8 µm. Axial area narrow, expanded to form an asymmetrical angular to nearly elliptical central area. Raphe filiform, straight, with external proximal ends dilated, straight, and distal ends distinctly hooked. Striae obviously lineolate, radiate near the center, becoming strongly convergent at the apices, 14-16/10 µm. Rare.
