Bizarre Diatom? (solved)

Images made through a microscope. All subject types.

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Frez
Posts: 150
Joined: Sat Feb 02, 2008 10:14 am

Bizarre Diatom? (solved)

Post by Frez »

Well this is an odd one. It's shaped like an Amoeba test. Since it was found in a fossil deposit from Oamaru, it's doubtful that it is. I have never seen a test survive the rigors of fossilization or the acid bath used to clean the diatomite. It would have to be siliceous meaning a radiolarian or diatom. What appear to be punctae indicate a diatom, but the overall shape says radiolarian. What do you think?

Many thanks to Peter for the ID.

Thanks
Frez

Image
Last edited by Frez on Sun Oct 21, 2012 12:49 pm, edited 1 time in total.

Jacek
Posts: 5354
Joined: Sun Oct 02, 2011 7:00 am
Location: Poland

Post by Jacek »

Beautiful, looks like a jug, amphorae

Cactusdave
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Joined: Tue Jun 09, 2009 12:40 pm
Location: Bromley, Kent, UK

Post by Cactusdave »

Pretty sure it's not a diatom. I'm going to vote for Radiolarian.
Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear

Peter M. Macdonald
Posts: 182
Joined: Tue Jan 20, 2009 2:59 pm
Location: Berwickshire, Scotland

Post by Peter M. Macdonald »

Frez,

What you have here is a small-headed flat turnip! Or, to be more precise, the radiolarian Plannapus microcephala. The generic name refers to the flattened turnip-like shape of this species - see Barry O'Connor 1997 "New Radiolaria from the Oligocene and early Miocene of Northland, New Zealand" in Micropaleontology, vol 43, pp. 63-100.

I vividly remember when I bought some Oamaru diatom slides and put the first one under the microscope. This was my first look at Oamaru fossils in the flesh. I knew what to expect with the diatoms, but was really excited to see that some of the slides had as many radiolaria as diatoms. They really are such beautifully sculpted things.

Your picture, being a well executed stack, is much better than any of those in O'Connor's paper.

Regards,
Peter

Frez
Posts: 150
Joined: Sat Feb 02, 2008 10:14 am

Post by Frez »

Hi Peter

Thanks for the excellent ID! After studying Oamaru slides for almost a decade, this is the first time one of these turniped, err...turned ip, turned up! :wink:

http://www.radiolaria.org/image.htm?sp_ ... ivision=27 has some examples of the O'Conner plates you may have been referring to.

Thank you again
Frez

Peter M. Macdonald
Posts: 182
Joined: Tue Jan 20, 2009 2:59 pm
Location: Berwickshire, Scotland

Post by Peter M. Macdonald »

Frez,

Yes - those are the plates. They look a little better in the original than they do on the web.

I like the idea that the seventh picture is a photo by Haeckel! His multi volume Die Radiolarien is available from the Biodiversity Heritage Library. He was the original author of your species, although he placed it in the genus Dicolocapsa.

Peter

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