Two examples of Asterolampra insignis from Kreyenhagen shale, California, USA. Mounted in Sirax and dated August 1939. Prepared by Samuel Henry Meakin. Olympus BHB microscope using 450nm LED light. As well as the arrangement, I imaged each one individually using the 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. Image stacks prepared in Zerene (Pmax), 64 images for the one on the left, and 44 for the one on the right. Some stacking artifacts, mainly in the center of each one, which I often get with Asterolampra and Asteromphalus diatoms.
Asterolampra insignis A.W.F.Schmidt 1888. Published in: Schmidt, A.[W.F.] (1889). Atlas der Diatomaceen-kunde Series III: Heft 35-36 [“Heft 29/30”]. pp. pls 137-144. Aschersleben: Verlag von Ludwig Siever. Plate 137, Figures 1-3.