wolfnipplechips wrote:I'm begging to wonder if indos modify their shells to make a head notch.

One of mine came in shells that were notched that same way, but I haven't seen any do it to their new shells...so... I dunno. Maybe something for peeps to look out for when they get indos in!

Two of mine came in notched turbos. One is still being worn, but here's a picture of the other:
It could be something that occurs over generations of crabs using the same shell, each chipping away in their own time.
Edit: I went back through some discarded shells and found more evidence of such modifications.
A broken turbo with the notch. It could just be a coincidence that it broke into the standard shell-notch shape (if i may be so bold as to go ahead and assert that it's a common practice), but there are markings and uneven spaces on the notch consistent with the other notches.
There's an m-shape chipped into this one where a notch would be. This is most likely from natural wear and tear, but modification is a possibility.
This one has better evidence of modification. The view of the inside gives us a better look. You can clearly see a shallow notch in the shell where the confirmed modded shells' notches are. Perhaps in an early generation of modification?
10 C. brevimanus