Fossil marine 'thingy'

75RR · Post by **75RR** » Wed Aug 27, 2014 3:15 pm

Pyxilla johnsoniana: not such an "unproductive sample" after all!

http://www.oamarudiatoms.co.uk/photo_5703304.html

Going to have to read-up on diatoms, that one threw me.

Very nice images, can you provide some info?

vasselle · Post by **vasselle** » Wed Aug 27, 2014 5:43 pm

Hello
Superbe

Cactusdave · Post by **Cactusdave** » Thu Aug 28, 2014 2:16 am

That Pyxylla really is a remarkable diatom and in an excellent state of preservation, with what must be a fragile 'horn' intact. One I don't think I've ever seen before. A nice find Beats.
I wonder if those sterrasters might also be found in the Barbados fossil Radiolaria deposits. Some of those also tend to be very spicule rich. Maybe its also a case of needing the correct geological age of the deposit for the sterraster-bearing sponges to be common in the fauna of the time.

BJ · Post by BJ » Thu Aug 28, 2014 6:08 am

Hi,

possible sterraster fossils are known from the cambrian and well preserved ones from the jurassic onwards. They occur here (Portugal) in a miocene deposit near me.They are produced by one group (family) of sponges, the Geodiidae. They are most common in very deep water on soft muddy bottoms, but there are some species in shallow water even occuring in the intertidal.

Pyxilla = one weird diatom !!

thanks for posting the collage - beautifully crisp,

regards,

brian