In my eyes I see similar traits in all these pearls. They are all dark, and have thin lines circling the pearling, also, It seems to me from the pictures I have seen, that they dont exhibit these markings until fully mature.
This brings me to a few questions. Are they from a specific locale? Or is it a marking development, that we dont see until fully mature. Similar to eclipsing on Leos, (which is the theory I side with.)
Not all Leos seem to eclipse at adult size, BUT a good portion do. The Male Pearl Mike has for sale right now has these markings -
http://www.monsterfishkeepers.com/forums/showthread.php?p=3991520#post3991520
Some on his site have them as well -
http://h2ocustomaquatics.com/pearl.html
RoyalRay has some spectacular specimens -
http://www.monsterfishkeepers.com/forums/showthread.php?t=151865&page=5
Likewise, second pic from Aquaman looks to be developing these markings
http://www.monsterfishkeepers.com/forums/showthread.php?t=278408
I think the pearl MNStingray recently acquired is a good candidate to keep an eye on -
http://www.monsterfishkeepers.com/forums/showthread.php?t=304897
Im attaching some pics of young wild caught Pearls that look like they are starting to develop these markings, and lastly, a couple pictures of the most intense pearls Ive seen online
(Can you imagine that last Pearl crossed with a galaxy P14??
Perhaps some of the members who keep these, or have experience with adult pearls can share their thoughts.
On a side note....how can you see these rays and think they are Marble Motoro's??