Triceratium foveatum from Chalky Mt., Barbados. Single example on the slide. Prepared by WA Firth. 63x Leitz Pl Apo 1.4 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 31 images stacked in Zerene (Pmax).
Accepted name Entogoniopsis foveata as discussed in Jakub Witkowski, Patricia A. Sims, Nina I. Strelnikova & David M. Williams, “Entogoniopsis gen. nov. and Trilamina gen. nov. (Bacillariophyta): a survey of multipolar pseudocellate diatoms with internal costae, including comments on the genus Sheshukovia Gleser”, (Phytotaxa 209), 89 pp, Figures 179-192, available here.
I have another T. foveatum, by WA Firth, but from Springfield, Barbados here. Certainly similar but is it close enough to be the same species? Not sure on that one, but for now I will go with the label name.