Sponge or Coral

[kpfransen]

I found this in eastern Iowa and was unsure if it was coral or a sponge. Anything would be helpful!

[aek]

Coral

[Myrmica]

I agree; coral.  Sponges don't have the same sort of regular pattern of 'pores'.

[Rockwood]

I disagree. This does not appear to exhibit the level of organization seen in coral.

Sponge seems quite possible to me, but I'm not at all sure.  

[TqB]

Welcome to the forum!

I think it is a weathered coral. It seems to be a heliolitid such as Propora sp., with short septal ridges and irregular coenenchyme between the corallites.

 

For once, a shot of it dry might help as there are a lot of obscuring reflections. Or, perhaps even better, try just submerging it in water with the camera pointing down from straight overhead - this can bring out a lot of detail without the reflections.

 

Edited June 1, 2021 by TqB

[Rockwood]

I had considered it. Perhaps not closely enough. Man ! That would be an ugly specimen.

No offense intended.