A strew slide from Ngongotaha, New Zealand (spelt Ngongotaka on the slide). Prepared by Mike Samworth. Mounted in Pleurax and dated July 2000. Lot’s of a Surirella sp. (more on this in a minute) but some other species as well. Olympus BHB microscope using 450nm LED light. 40x Leitz Pl Apo NA 1.00 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, brightfield lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 59 images stacked in Zerene (Pmax).
So, what species of Surirella is this? Initially I did a search for Surirella and Ngongotaha and came across a link to a thread on Photomacrography.net where someone had shared an image of something which looked like this and had called it Surirella laudata. I searched for this name, and could find very little in terms of other mentions, and it didn’t appear in Schmidt’s Atlas. However that name does appear in Päule Heck’s publication “34 site slides of tropical freshwater diatoms from Albert Elger’s microscopy laboratory”, 2012, along with an image which looks very much like this. In a photo on page 98 of that document it shows a hand written note, with what looks to me to be some shorthand which says ‘New species!’ next to S. laudata. I also posted an image on the Diatom Imaging Facebook page, and another name was proposed – Surirella hastata – along with images from an eBay advert of a slide of this by Watson and Sons. The images (at least the low resolution images from eBay) also matched this one and had the name on the slide. S. hastata does appear in Schmidt’s Atlas (plate 21, Figure 4), and it does look like the one I shared. That name also appears in the document “Studies on Australian and New Zealand Diatoms IV.—Descriptions of Further Sedentary Species”, Transactions and Proceedings of the Royal Society of New Zealand, Volume 88, 1960-61, pp. 669-698, plates 50-56. S. hastata is described a living in Australia and New Zealand, and the image on Plate 55, Figure 193, although only showing part of the diatom does look like mine. So I am left with 2 potential names for this one – S. laudata, and S. hastata. Could these actually be the same – they both look like mine, but I am not a diatom naming expert, so will leave this discussion as it is at the moment, and say it is a Surirella species, possibly S. laudata or S. hastata.