In todays post, we will be talking about the Genus Craticula. I particularly like this genus because I believe it to be so pretty, that is when you get an uninterrupted specimen without debris or sediment obscuring the view. However, having said that, let’s dive right in.
What makes this diatom so unique is more or less one key feature; the striae are parallel or nearly parallel. As soon as you see that feature, the mind should jump right to this particular genus. According to Diatoms.org some other key features are:
- Striae parallel, or nearly parallel
- Valves lanceolate
- Central area small or absent
- Distinct internal valves may be present
The size range is very broad also, some species can be as small as 7 micrometers ad as large as 274 micrometers. Obviously, with the larger species, the parallel striae will be more pronounced and very clear to see. As you can see, the morphology of the different species also vary. However, the parallel striae will always stand out!
As always, Algaebase has more information regarding the original publication, which is always a fun read. Also check out the ANSP Algae Image Database, they have some very cool algae pictures of both diatoms and soft algae.
The picture below, has some problems with it; such as a whole lot of debris and sediment that block the view of the diatom and make the picture very overwhelming. However, having said that, that was the best specimen that I could snag a picture of. But if you look carefully, the parallel striae can be easily seen in the very middle of the diatom…a very unique feature! Below enjoy the magnificent view of Craticula cuspidata. Try to key it out by looking at the morphological features. I believe the size on this guy was around 120 micrometers.
Science Thursday 