Wow that is a long one.
Good job of digging too and no doubt took some patience to get that all out.
What kind of location was it in ?
I found one a few years back, at the bottom of a bluff that had a long neck like that. It was deep and between some rocks and I could not get the root hair - hated that.
All I could count on it was 35 flats. As you get down closer to the main root the flats sort of dissapear.
I sort of expect that when a root is in a location like that, where soil is constantly sliding down hill and accumulating that the root neck may grow longer. I have seen them with 35 flats on them that had a lot shorter neck than this one did.
Just wondering if yours may have been in a location like that.
Below is what mine looked like.
TNhunter