What is the ring of triangles around Kermit's neck?

Looking at pictures of frogs, I have been unable to find one that has similar markings. For example, take this picture of a typical frog:

Kermit, of course, has a signature ring of triangles around his neck:

So far I have been unable to find any credible evidence of why he has that ring or what it is. No interviews with Jim Henson, for example.

One bit of speculation is that ring hides a seam between the puppet's head and body, but again, no definitive proof. Another is that Kermit started out as a lizard or nameless animal and later turned into a frog: however, would his appearance not be updated to match his species? Again, lack of credible evidence here stating one way or another.

This thread on Reddit touches on the various theories and is a good, concise overview: however, it offers no credible evidence to back up any of the claims.

Why does Kermit the Frog have a ring of pointy flaps around his neck?

Note: if you follow the Wikipedia links for Kermit there are some articles that assert he was species-less at first with Henson quotes to back it up: however, upon becoming a frog I would expect his features to match that of a frog as close as one could expect a fictional anthropomorphized muppet to match. His original species is largely irrelevant to his frog features.