To identify a species, you need the number of striae in 10 µm and lineolae in 10 µm.

N. spartinetensis : average 15 striae in 10 µm and 25 lineolae in 10 µm (see Witkowski, A., Sullivan, M. J., Bogaczewicz-Adamczak, B., Bąk, M., Rhiel, E., Ribeiro, L., & Richard, P. (2012). Morphology and distribution of a little known but widespread diatom (Bacillariophyceae), Navicula spartinetensis Sullivan et Reimer. Diatom Research, 27(1), 43-51.)

N. flanatica : 10 striae in 10 µm and 20 lineolae in 10 µm (see Witkowski, A. (2000). Diatom flora of marine coasts I. Iconographia diatomologica, 7, 1-925.)

It could be also N. phyllepta, very commun in mud (as N. spartinentensis). For this species, shorter than N. spartinetensis and N. flanatica, striae are also 15 in 10 µm but with 40 lineolae in 10 µm (see Witkowski, A. (2000). Diatom flora of marine coasts I. Iconographia diatomologica, 7, 1-925.)

I hope this help.

Regards,

Vona

This is doubtless a Navicula species, but is is difficult to identify in species level.

Similar to Naviculaceae, the details of species is confused.

This is either Navicula spartinitensis or Navicula flanatica. Both are intertidal diatoms. Check this paper:

http://www.tandfonline.com/doi/abs/10.1080/0269249X.2011.647772#.U38cEPldXiM

N. salinarum may also be possible.

Is Portishead on the coast? Were there more than one valves seen? Navicula flanatica or salinarum may be possibilities. I am more used to LM images. Nice photo!

Have you photographs of the TEM?

Hello HuiLing,

I agree with Lourenço Ribeiro , your diatom looks very similar to Navicula spartinetensis Sullivan & Reimer

It looks like Craticula submolesta, but I've never seen it on SEM.

It is possible to be "Navicula goersii".

It's definitely not N. salinarum and N. goersi!

I would guess a small form of N. flanatica -- but I am unfamiliar with N. spartinentensis. Does anyone have a photo or reference for that species to share?

I'm just happy I knew it was Navicula. Pennates are tricky. Beautiful image!

It is navicula flanatica, regards

I agree it is Navicula flantatica,

Best regards

Thanks everyone.

Here is a LM image.

and more SEM pictures

and more SEM pictures

and more SEM pictures

Hi, it is very similar to N. menisculus var.grunowii.

To identify a species, you need the number of striae in 10 µm and lineolae in 10 µm.

N. spartinetensis : average 15 striae in 10 µm and 25 lineolae in 10 µm (see Witkowski, A., Sullivan, M. J., Bogaczewicz-Adamczak, B., Bąk, M., Rhiel, E., Ribeiro, L., & Richard, P. (2012). Morphology and distribution of a little known but widespread diatom (Bacillariophyceae), Navicula spartinetensis Sullivan et Reimer. Diatom Research, 27(1), 43-51.)

N. flanatica : 10 striae in 10 µm and 20 lineolae in 10 µm (see Witkowski, A. (2000). Diatom flora of marine coasts I. Iconographia diatomologica, 7, 1-925.)

It could be also N. phyllepta, very commun in mud (as N. spartinentensis). For this species, shorter than N. spartinetensis and N. flanatica, striae are also 15 in 10 µm but with 40 lineolae in 10 µm (see Witkowski, A. (2000). Diatom flora of marine coasts I. Iconographia diatomologica, 7, 1-925.)

I hope this help.

Regards,

Vona