Nymph ID (HUGE?)

[Gorosaurus]

I was out on Manada this week and I found this bruiser under the first rock I turned over. I didn't see any others this size all day, but this is probably the largest I have yet come across (especially on that stream!).

Any idea what this is? Including that tail it's nearly 2 inches long. The hook pictured is a size 12

 

[Maurice]

March Brown

 

[Gorosaurus]

Wow, thanks!

 

[IdratherbePhishing]

Absolutely get ready goro.