A linear arrangement of 5 Aulacodiscus. Names on the back of the slide which I will come back to in a minute. Label says they are from Oamaru, New Zealand with Oligocene in pencil. Mounted in Styrax. No makers name but this looks like it was made by JA long. Olympus BHB microscope using 450nm LED light. 20x Nikon Plan Apo NA 0.65 objective. Olympus Aplanat Achromat condenser, oblique lighting. 2.5x Nikon CF PL photoeyepiece. Monochrome converted Nikon d850 camera. 41 images stacked in Zerene (Pmax).
Back to the names. I’ll give the names on the slide and comments on them. 1-5 run from the lower left to upper right.
1. Aulacodiscus Russian tuberculatus? Could be Aulacodiscus tuberculatus also known as Aulacodiscus archangelskianus. This could be correct, but why is it in an Oamaru arrangement (based on the label on the front of the slide)? Not sure, however it doesn’t look like any specific Oamaru Aulacodiscus.
2. Aulacodiscus novae-zealandicus. This looks like Aulacodiscus sollittianus var. nova-zealandica.
3. Aulacodiscus oamaruensis. Not sure about this, it looks more like Aulacodiscus amoenus var. amoenus to me.
4. Aulacodiscus crux var. subsquamosa. This looks to be correct.
5. Aulacodiscus huttonii. This looks to be correct.