Good morning Cymbella upload a photo of sp.
I would not know but I say the species is C. parva and C. helvetica.
Regards, Francisco.
(https://www.mikroskopie-forum.de/pictures004/153208_30627877.jpg) (http://s1373.photobucket.com/user/catetocateto/media/DSCN3968_zpsc9d852bf.jpg.html)