you sure it was eaten and didn't melt or something?
nothing on your list would have eaten it, so unless you have a nefarious hitch hiker, i'm not sure what happened to it.
Are you sure you have no urchin? My long spine moves over my kenyas and it's gone. Right done to the frag, in 20 minutes.
I wish something would have eaten mine...I'm still cleaning up dropped branches and I took it out 2 months ago!