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Dictyocha speculum Ehrenberg 1839 (Octactis speculum Chang 2017)

Kingdom, Chromista; Phylum, Ochrophyta; Class: Dictyochophyceae; Order: Dictyochales; Family: Dictyochaceae; Genus: Dictyocha

Scanning Electron Microscope (SEM) images of the silica skeleton of the silicoflagellate Dictyocha speculum (Octactis speculum Chang 2017, Guiry et al. 2020). A silicoflagellate with an external silica skeleton, having 5-12 radiating spines, but normally six spines. Skeleton is most often hexagonal, with two rings of equal thickness, connecting struts and pikes on the basal ring.(Chang et al. 2017). Variable number of chloroplasts. Marine species.

Methods:

Specimen collected with a 10 μm mesh plankton net, Trincomali Channel, Spanish Hills Wharf, Galiano Island, Gulf Islands, British Columbia, Canada. Non-cleaned environmental sample. Scanning Electron Microscope: Hitachi 4700, University of British Columbia, BioImaging Facility. Thank you to Elaine Humphrey for preparation and SEM assistance.

References:

Chang, F.H., Sutherland, J. & Bradford-Grieve, J. (2017). Taxonomic revision of Dictyochales (Dictyochophyceae) based on morphological, ultrastructural, biochemical and molecular data. Phycological Research 65: 235–247, 22 figs.

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.

Guiry, M.D. & Guiry, G.M. 2012. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on May 31, 2020.

Hallegraeff, G.M. (2005). Silicoflagellates. In: Antarctic marine protists. (Scott, F.J. & Marchant, H.J. Eds), pp. 251-254. Canberra & Hobart: Australian Biological Resources Study; Australian Antarctic Division.

Parkinson, P. (2002). Ontogeny v. Phylogeny: The Strange Case of the Silicoflagellates. Constancea, 83. University and Jepson Herbaria, University of California, Berkeley.

Jahn Throndsen, (1997). The Planktonic Marine Flagellates. In: Identifying Marine Phytoplankton. (Tomas, C.R. Eds.). San Diego: Academic Press.

A) Hôte = Pacifastacus leniusculus et branchiobdelle sur la pince gauche.
B & C) Branchiobdelles sous le propode de la pince.
D) Branchiobdelles sur le propode de la pince.
E) Branchiobdelles sur le branchiostégite gauche.
F) Habitat & site de collection.