Does a Dracolich possessing a new corpse reform as its original type or as the corpse's type?

Question

In the 5th Edition Monster Manual, it states the following under the Dracolich Phylacteries section:

If a dracolich's physical form is ever destroyed, its spirit returns to the gem as long as the two are on the same plane. If the gem comes into contact with another dragon's corpse, the dracolich's spirit can take possession of that corpse to become a new dracolich.

Emphasis mine.

My question is, does the dracolich assume the new corpse's type? For example, if an Ancient Black Dracolich is destroyed, and then its gem comes into contact with an Adult Silver Dragon's corpse, would it reform as its original self (Ancient Black Dracolich), or become the new corpse type (Adult Silver Dracolich)

If the former, would any dragon corpse do? As the restrictions to become a dracolich require ancient or adult, but the text for consuming a corpse just specifies "another dragon's corpse." (Seems silly that an Ancient dracolich could regain full powers from coming in contact with a wyrmling, but that popped into my head when writing this question.)

Answer 1

Since this is effectively the creation of a new Dracolich, the following are true:

• It would fail without an Adult or Ancient Corpse
• It retains all the features of the new body

Here's my rationalization of those two.

By inhabiting a corpse of a newly (or heck, not so newly) slain dragon, the Dracholich is not simply acquiring a new body (though it is that too), it is in essence becoming an entirely new Dracolich. Thus it would need a properly aged corpse as conversion is not possible on younger Dragons (it would also need to be a true Dragon, and not a poser).

The other half of this is that the new body is tied to a specific type of Dragon and thus has it's stats/abilities etc and not the Dracolich's previous. It's a new Dracolich and not a rerun.

If I was going to use this feature in a campaign though, I would feel very free to experiment beyond these bounds. An ancient zombie dragon that has found itself bound to a wyrmling's corpse for reasons unknown could provide a very compelling plot possibility.