Biddulphia johnsoniana from Cambridge, Barbados. Single example on the slide. Unknown maker. Olympus BHB microscope using 450nm LED light. 63x Leitz Pl Apo 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, slightly oblique lighting. 2.5x Nikon CF PL photoeyepiece. 11mm spacer removed from the tube to the camera. Monochrome converted Nikon d850 camera. 94 images stacked in Zerene (Pmax).
Synonymised names: Cerataulus johnsonianus (Greville) Cleve, 1885. I do have an example of C. johnsonianus from Nagy Curtos, Hungary (see here) and while the overall shape is similar the surface morphology looks very different to me. I remain to be convinced that these are the same……
I recently acquired about 60 slides by this maker, so if you want to see others by them, search for AAAAA in the Search option at the top of the page, and I’ll include this in each of the pages for them.