Quite a special slide this one. An example of Craspedoporus briggeri from Indian Ocean, Scripps D080, 123-D-L. Slide No. 2028. Single example, 6P (6 processes), 141µm diameter (I measured 142µm in ImageJ – close enough). Mounted in Styrax/Aroclor, and dated January 1976. Metal coverslip spacers. Prepared by Richard Gosden. Olympus BHB microscope using 450nm LED light. 40x Leitz Pl Apo NA 1.00 objective, oil immersion. Olympus Aplanat Achromat condenser, oil immersion, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 83 images stacked in Zerene (Pmax). Couldn’t get close enough to use the 63x Leitz, which is a shame. The extra resolution would have been nice for this, but I was only able to image the top half before it hit the coverslip ring. Rimoportulae seen in between the ocelli.
Craspedoporus briggeri R.Ross & P.A.Sims, 2000. Published in: Ross, R. & Sims, P.A. (2000). A revision of Actinodiscus Greville, Craspedoporus Greville and related genera (Eupodiscaceae). Diatom Research 15(2): 285-347, 130 figs. Page 317, Figures 60-69. Type Information: Mascarene Ridge, Indian Ocean (10°25’S, 63°15’E). 3115 m. depth. Dredge sample. Middle to late Eocene, Dodo 123-D1.
I’ve included a screen grab from the Ross and Sims paper, showing how their Figure 60 compared with the one on the slide. On theirs the scale bar is 20µm.
A rare diatom and amazing to see a complete one.