I have found two specimens of this mysterious fossil in our museum collection. I expect it to be a tracefossil of some sort.
they are both found in the Uppermost Maastrichtian chalk of Stevns Klint, Denmark
Both specimens are very similar in morphology.
I have attached a photo of the best specimen.
Best wishes
Jesper
Hi Jesper,
Looks a bit like Lepidenteron, a passively filled burrow lined with fish scales, for instance (if it is not a sponge). Unfortunately, the image does not allow to figure out what is in the wall, so please check on the original specimen! There is also a meibenthic burrow preserving its producer in the branch to the lower left.
Cheers, Dirk.
Hello Jesper,
I agree with Dirk ... at first glance it looks like a trace fossil or sponge ... to distinguish between both we need to see the „wall“ in more detail ...
Best wishes,
Mike Reich, Munich
Hi Dirk and Mike
Thank you very much for your suggestions. I have been looking closer at the specimens. There seem to be no wall lining in them, only a slightly difference in colour and perhaps something that could look like spongie tissue. The "lobes" of the fossil are flattened structures about 1 mm thick, I have made some photos of the wall lining and a section through one lobe. But there are frustratingly little details to look at. I have also attached a photo of the second specimen, to show the close similarity in morphology.
Hi all,
Thank you very much for your different input and suggestions, that has given me some ideas to work on. Hopefully I will be able to identify the specimens one day😀
Best wishes
Jesper
the pattern is like a some arthropod trace fossil on front cover of the book Ichnoentomology by Jorge Fernando Genise
There is indeed a striking resemblance with this Cellicalichnus but this specimen has been found in a marine sediment of the early Paleogene, not in a paleosoil. I don't have access to the book, do we know what kind of insect makes burrows of such a shape ?
Hi all,
Thank you for your interesting suggestions. As Nicolas Thibault mentioned (thank you for dating the sediment), the specimens are from lowermost Palaeocene (Danian) marine limestone of Denmark. They were wrongly labelled in our database as upper Cretaceous.
Cheers
Jesper
Nicolas, this ichnogenus was made for bee activity, Efectively is fun on paleosoils...
Doesn't look spongy to me, sorry Chistian. It is most definetly a burrow or cave like structure. The walls are stiffened to prevent for collapse in the soft muddy carbonaceous sediment and surely hardened with some organic substances from a body fluid of some kind. The pattern of four vault like chambers is perfect symmetrically designed. I suppose each of these vaults are made for protecting an egg or a larvae. The constructor should be a small athropod, maybe a cructacean. But keep in mind that there were some marine insects and marine spiders on this planet for some time now...
Good luck with the description of this fossil.
Hi all,
Thank you very much for all your input and suggestions. It seems the mystery has just been solved. Marcus Bertling has just published a paper in phytotaxa about this kind of fossil, which is definitely a trace fossil that goes by the name Tetraphyllum dubium. It is a trace that was first reported from the Campanian of Germany and initially thought to be a plant fossil, but Marcus has restudied it and makes a very convincing case that it is indeed a trace fossil.
I don't have a subscription to this journal. Does the paper say what kind of animal could possibly do that sort of burrows ? It is really a nice peculiar trace fossil.
