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:

[![enter image description here][1]][1]

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

[![enter image description here][2]][2]

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?][3]

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.

  [1]: https://i.sstatic.net/kty3C.jpg
  [2]: https://i.sstatic.net/T7sbt.jpg
  [3]: https://www.reddit.com/r/NoStupidQuestions/comments/2igite/why_does_kermit_the_frog_have_a_ring_of_pointy/