The spots on a spotted salamander (Ambystoma maculatum) are much like our fingerprints - each animal has a unique number and pattern, and it's highly variable. Though rare, or at least uncommon, occasionally spotted salamanders are found that have almost no spots.
It turns out that in one population in eastern Massachusetts, there is a good number of spotless spotted salamanders (would that be A. nonmaculaum?). Every year I turn up at least one at this particular site. This fellow had four very small spots, one of which is visible mid-way down the tail. The others happen to be on the side facing away from the camera.
Hmm. I find at least one at this pool every year. Salamanders live 10 or 12 years in the wild. Hmm... Wonder if I have any pictures of him from last year...