There are now two Treasure Chests. The Alpha Chest and the Vanguard Chest. The Alpha chest is the treasure chest we all know and love. The Vanguard chest contains the special monthly items released since the introduction of the Alpha chest.
Interesting note: Malekus and Ambrosia (the Demi-Powers) are epic pulls from the Vanguard chest. This implies that the other three Demi-powers may become available to be pulled from future chests.