Genus: Diploneis.

Likely the marine diatom Diploneis bombus. Will require cleaned valves and SEM images. There are 215 species accepted taxonomically by: https://www.algaebase.org/search/genus/detail/?genus_id=43699&sk=0.

Possibly Diploneis vetula (A.W.F.Schmidt) Cleve 1894. Shim (1976). Marine Planktonic Diatoms of the Straight of Georgia. Phd. Thesis. UBC.

Diploneis bombus: p. 59. Planche (plate) 50 p. 121. Bérard-Therriault, L., Poulin, M. & Bossé, L. (1999). Guide d'identification du phytoplancton marin de l'estuaire et du Golfe du Saint-Laurent incluant également certains protozoaires. Publication Spéciale Canadienne des Sciences Halieutiques et Aquatiques 128: 1-387.