How to breed a Ghost Dragon

A Dodo Dragon can be bred by pairing an earth dragon with an air hybrid. For example: an Earth dragon and a Chrome dragon is reported to work. You'll know you have a Dodo Dragon if you get a breeding time of 16 hours. The egg is brown with a wind symbol on it.

Dodo dragons are a hidden dragon that started appearing April 13th. The description suggests that they may be in the marketplace soon, possibly with other new dragons.

Cave drawings of the dodo dragon were first discovered on Mooretoss Island long ago by the great explorer Lewis Dodoson. They depict an ancient, flightless, and rather clumsy dragon. For centuries it was thought to be extinct, but we now know that while the dodo dragon may be rare, it is certainly not extinct! I wonder what other dragons have yet to be discovered!

It is not clear at this time if this will be a limited time dragon.

Here is a video showing the successful Earth+Chrome combination:

Per the wiki:

The Sakura Dragon can be bred by using a combination of dragons whose elements include plant, earth, and fire. The in game splash message indicated that you must be level 11+ to breed this dragon.

You may have bred a Sakura dragon if you get a breed time of 10 hours, but you will have to wait till you see the egg to be sure, since it could be a Lava dragon as well. The egg is brown egg with three cherry blossoms on it, like this:

The sakura dragon is only breedable until May 3rd.