Actinotocarcinus crab (suspected)

I found this large concretion on the way back from fetching what I thought was an ancient net weight or anchor (turns out it wasn't!). It doesn't look like the usual Tumidocarcinus crab that is found near this location and the spikes make me think it is an Actinotocarcinus crab, requires further prepping!

 

Watch the video of it being found

Age: Miocene