Triceratium trisulcum from Hayti [Haiti]. Single example, underside view with the rim towards the coverslip. Unknown maker. Olympus BHB microscope using 450nm LED light. 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. 75 images stacked in Zerene (Pmax).
I am assuming the maker is basing the name on the examples in Truan y Luard, A. & Witt, O.N. (1888). Die Diatomaceen der Polycystinenkreide von Jeremie in Hayti, Westindien. Friedlander et Sohn, Berlin., 24 pp., 7 pls. The description and images are given above, and a translation shown below;
“Tricerceratium trisulcum Bail. var. Haytiana. T. & W.
Common. Plate VI, Fig. 15.
Tricerceratium trisulcum Bail. var. producta. T. & W.
Less common. Plate VII, Fig. 17.
These two forms differ greatly from the typical T. trisulcum (Prit. Inf. Plate VIII, Fig. 27), but cannot be specifically distinguished from it.”
Based on the images, I suspect the one of the slide would be Triceratium trisulcum var. haytiana. However it should be noted (as Truan and Witt did) that these example differ from the classical appearance of T. trisulcum, and as such I cannot rule that a more extensive search would produce alternative names for it.
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.