Copied from an update to the wiki-FAQ:
What are the strange symbols after (insert Wyrm here)'s color code?
As part of a recent upgrade to the data cards, some Wyrms may now have little symbols next to their color codes. What are they? The simple answer is: These represent some hidden feature of the Wyrm that isn't represented by it's Physical Features list. Just what the symbols mean, and how you can breed for these hidden features is up to a keen eye, and handler experimentation.
^^^^^^^^^^^
Pre-emptive strike, since I know people are going to ask about these. =3
And no, I won't tell you what they mean, as it says, that's up to you to figure out.