Waldron Shale, Sponge?

[Misha]

Hello everyone,

Recently I was kindly sent some fossils by @connorp from the Waldron Shale in St. Paul Indiana.

One of these fossils was a piece of matrix which ended up separating due to some cracks, this revealed an interesting specimen that I am not too sure about the ID of. It is round, with rough surface texture and some fine patterns visible under magnification. To me, this appeared very similar to Lower Devonian Hindia sp. sponges I've found in NY, so I thought maybe it belonged to that genus. Looking into it the only sponge genus I can find from the Waldron is Astylospongia, and the specimens of this genus I've seen online look quite different from this example as although they're also round, but they appear to have different surface patterns and and an indentation on one side which I do not see here. I was wondering does anyone know what this may be? Is it a sponge like Hindia, a different species or preservation of Astylospongia or maybe not a sponge at all?

Thank you for looking, and for any help. It is really appreciated.

Misha 

[Misha]

Some additional shots of the object:

It's about 1.5 cm in diameter 

Edited April 30, 2023 by Misha