Oops I been an done it again!

[Fetishkat]

Any ideas what might have caused this damage?

The crank gears look fine.

Why just those teeth? I carried on riding for over a thousand miles after first noticing the rumble from below. 

Would having to bump start the bike a few times when the battery began to fail put to much stress on the gears?

Any ideas gratefully received 

Cheers

[Duckndive]

Any other shrapnel in the sump / strainer / filter ?