Stictodiscus haytianus from Jérémie, Hayti [Haiti]. Single example on the slide. Prepared by JA Long. 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. 50 images stacked in Zerene (Pmax). The surface of the diatom appears to be textured, especially visible in the central region – a crop from a single frame imaged using extreme oblique lighting is shown to demonstrate this.
Stictodiscus haytianus is written about in: Truan y Luard, A. & Witt, O.N. (1888). Die Diatomaceen der Polycystinenkreide von Jérémie in Hayti Westindien. pp. [1]–38, incl. 7 pls [I-VII]. Berlin: Verlag von R. Friedländer & Sohn. Page 19 and Plate IV, figures 27-29. A translation of the section is given below (I’ve added comments in square brackets where Google translate made less sense);
“S. Haytianus nov. sp. T. & W.
Extremely robust form, with a well-developed, sculpted margin. Folding is weak, radial at the margin, barely noticeable, somewhat stronger in the center, dichotomous. Very strong puncta, forming radial rows more than half the radius of the shell [frustule]. Each radial row begins with a double dot [double punctum] at the margin; this is followed by elliptical and finally round puncta, which become smaller towards the center. Irregular puncta in the middle, with a few smaller puncta always present in the center.
Common. Pl. IV, Figs. 27, 28, 29.
This beautiful form is characteristic of the Jérémie material; it almost always occurs in a round shell [in a circular form].”
I find it interesting that this is described as ‘Common’. I wasn’t able to find another image online apart from the ones in the book. Speaking of which I find Figure 27 looks to similar to this one, but I am less sure of 28 and 29.
Synonymised names: Cladogramma haitianum (Truan & Witt) Kuntze, 1898 · uncertain > unassessed.