So a metataxon lacks recognizable autapomorphies (autapomorphies =
derivations common to its supposed "group").
Autapomorphies = derived characters unique to itself (auto- = self).
Metataxa of the right stratigraphic age therefore enter consideration for
possibly being direct ancestors of some known clade. (For example, if
*Lagosuchus* were older than *Marasuchus*, it could be its ancestor.)
Unfortunately, this is the farthest we can go, except maybe in cases of an
extremely good fossil record (like diatoms in the mud on the ocean floor).
We can't tell, for example, whether autapomorphies were present in
unpreserved parts of the organism.