Mappa question

[shellz]

Not sure if this is correct forum to post this, I apologize if I have the wrong forum.  My question is...

What is the difference between a mappa contraria and mappa subsignata?  To me, a map cowrie is a map cowrie, maybe clear pattern, maybe distorted pattern, maybe pink, or maybe some other color (green, red, purple), but it is still a map cowrie.

I noticed that mappa subsignata generally is dealer priced higher than a mappa contraria, and mappa contraria is dealer priced quite a bit higher than one tagged as just a map cowrie. The reason I ask is that I have a slightly unusual map cowrie whereby the top pattern is kinda hazy and not too clear, just wondering if it may be one of the two mentioned above. Thanks in advance.