An arrangement with 123 forms from Conset, Barbadoes (Barbados). Prepared by Horace George Barber. Mounted in Naphrax and dated February 1950. An amazing arrangement which unfortunately has some significant issues with the fixative/mountant which has lead to some diatom movement, and others being very hard to image. Olympus BHB microscope using 450nm LED, either brightfield or oblique. Stacking done in Zerene using Pmax. I have a lot of questions about my naming of these, hence plenty of question marks after the names.
Araniscus lewisianus. I’ve also seen the name Coscinodiscus lewisianus var. similis. Brightfield lighting. Fairly sure on the name for this.
Asterolampra / Asteromphalus sp.. Brightfield lighting. A bit like Asterolampra punctifera, but this one has one thinner portion at the 12 o’clock position. Also has some similarities to Asteromphalus humboldtii. But I am really not sure on this one.
Asterolampra marylandica ? Brightfield lighting. Fairly sure on the naming for this one.
Asterolampra sp. Oblique lighting. The mount/fixative issues has resulted in some quiet severe artifacts to this one.
Aulacodiscus sp. ? Oblique lighting. A nice example and looks to be intact. Viewed from the underneath. Some very obvious dark spots across it, but so far I have not found a match for it.
Cestodiscus sp. (C. fusiformis ?). Brightfield lighting. Viewed from underneath/inside. I am sharing 2 examples of Cestodiscus from the slide. I think this one could be C. fusiformis.
Cestodiscus sp. (C. rhombicus ?). Brightfield lighting. Viewed from underneath/inside. I think this one could be C. rhombicus.
Goniothecium rogersii. Oblique lighting. Viewed from underneath/inside. Fairly sure on this one.
Unknown (Stictodiscus sp.?). Oblique lighting. Viewed from the underside. This one is very unusual, and even going with a Stictodiscus species is a bit of a stretch. Looking through Schmidt’s Atlas, I did come across something on Plate 131, Figure 4, which says “according to Grunow, similar to Stictodiscus Kittonianus Grev.”. Publication details for Stictodiscus kittonianus Greville 1861: 79; pl. X: fig. 2-3. Published in: Greville, R.K. (1861). Descriptions of new and rare Diatoms. Series IV. Transactions of the Microscopical Society, New Series, London 9: 79-87, pl. X. There are similarities to S. kittonianus, but I am not 100% convinced. Perhaps an abnormal form?
Synedra sp. Oblique lighting, single unstacked image.
Overall, despite the damage to the mountant/fixative on the slide, there are plenty of nice diatoms to image.