Jellyfish Impression?

[jpc]

Hi all....

A visitor brought this into our museum this morning. Very unusual. Of course she wanted to know what it is. Two of us independently thought jellyfish impression. But things like that are super rare. It is from the Jurassic marine deposit here in Wyoming. The Fm has some invert impressions and tons of belemnites and the occasional ichthyosaur bones and ammonites. There are worm traces on this surface that you might be able to see. Anyone have any insights into jellyfish fossils? I am familiar with the Mazon Creek Essexellia and such, and Solnhofen jellies, but this is different. That's my thumb for scale.

 

 

 

 

Any other thoughts... if it is not a jellyfish... what the heck is it? Impression of....????

Thanks and happy fossiling... its getting to be springtime. Wait... it is Spring. Happy Equinox folks.

jpc

[Uncle Siphuncle]

looks like jelly to me. in the texas lower cretaceous we have a similar form, kirklandia texana... still need to find me one!

[PRK]

Yes--- I like that. Kirkland-ia. Ha ha. But yeah that's a cool looking fossil!

Edited March 20, 2013 by PRK

[Carl]

My gut also starts with jellyfish, but I could also see something like an aerial lignotuber of an araucarian (say THAT 3 times fast!) or some other botanical bit like a fruit or pod. I couldn't find many shots of the lignotubers on the Web but they look reasonably similar: http://louisvillefossils.blogspot.com/2012/02/arucaria-mirabilis-fossil-seedlings.html.

[Auspex]

The only other thing I can think of is the bottom of a feeding burrow, where the sediment happened to separate at just the right point.

[piranha]

It looks a lot like Palaeosemaeostoma from the Jurassic. In the past these forms have been interpreted as medusae although these 'medusiform' ichnos are now grouped as gyrophyllitids united by the ability to inflate parts of their body.

[piranha]

Just a brief follow-up for anyone interested here is the description on medusiform burrows (Seilacher 2007).

[Carl]

My new vote goes to Piranha. And no, I don't think it is a fossil piranha...

[jpc]

Thanks y'all. I'm not sure between Kirklandia and piranha's suggestion. But these are a ton better than I had five hours ago. Thanks.

[Evgeny Kotelevsky]

It can be imprint of top part of some Coeloptychiidae sponge (Foliscyphia or Troegerella)

Edited March 21, 2013 by Evgeny Kotelevsky

[piranha]

It can be imprint of top part of some Coeloptychiidae sponge (Foliscyphia or Troegerella)

There is a similarity in form but that family of sponges is Cretaceous and has no recorded occurrences in North America.

[jpc]

Yes--- I like that. Kirkland-ia. Ha ha. But yeah that's a cool looking fossil!

Could it be that guys named Kirkland like this ID? Jim Kirkland also emailed me with the same ID. Hmmmmm.....

[PRK]

I don't know about the actual ID, but the name is nice. And I don't know if COSCO in your area, but that KIRKIANDIA genus could be their version of FEDEXIA

[rocket]

how did it turn out? Could you find an exact determination for this one?

[jpc]

On 5/8/2022 at 4:31 AM, rocket said:

how did it turn out? Could you find an exact determination for this one?

rocket... what you see here is as far as we got.

 

 

[rocket]

do you remember if the surface has fine structures? 10 years ago, long time

I would agree with @piranha, looks like Paleosemaesostoma or Gyrophyllites. In earlier times it was assigned to Fodinichnia, but my last info was that it is unclear how it was builded. Seilacher (2007) described it in his book about trace fossils

Edited March 18, 2023 by rocket

[jpc]

I do not remember this thing at all, nevermind details of the texture.  And the owner took it with him.  I was actually surprised when I saw this post resurface yesterday... "What is this?  I posted about a jellyfish impression?!"