I hate to disagree with Dr. Leech, but I'll go out on a limb and argue that this is not A. utahana, because of the curled tip on the embolus that, to me, is visible in your photo. The tip of the embolus of A. utahana is supposed to be straight, not curled.

Not wanting to jump to a hasty conclusion, though, I pulled out a preserved adult male A. utahana that I collected a couple of years ago and took a good look at the palp under the microscope. I also compared it with the diagnostic drawing of the A. utahana palp in Guide d'identification des Araignes (Araneae) du Quebec by Paquin and Duperre (p. 29). Mine is identical to the diagnostic drawing. Both differ from the embolus shown in your picture in having a straight tip; there is no curl on it as appears in your photo.

Also, unless I am missing something, there is no other structure on the palp of A. utahana that I can see that resembles the curled-tip shape shown in your photo.

So, this is why I believe that your spider is a species other than A. utahana. With all due respect, could you ask Dr, Leech to take another look? I'm not a professional arachnologist, and if I am wrong I won't mind being corrected. :)

Also, if you still have the specimen could I possibly take a look at it?

I don't have the specimen, but I will get hold of Robin to see if he'll take a look at the images here.