The X in BitSharesX stands for eXchange. BitSharesX is live, it's the final chain. If there is to be any related offspring there will be a snap-shot from itself.
ProtoShares were renamed to PTS due to trademark issues, it's the same thing.
So PTS is or isn't the same thing as BTSX?
PTS was the first crypto launched by BM and I3, it is a more traditional "bitcoin-clone" type of currency but with a novel mining algorithm called Momentum that was meant to be CPU only. It turned out to be GPU mineable but only after a certain time, and is still being mined to this day although it has serious issues with it's difficulty due to large swings in mining interest due to snapshots.
PTS gives the right to claim parts in DACs based on your stake at the time of a snapshot, it was the case for BTSX at the end of february, and other snapshots that have been held since and future snapshots will all honor PTS.
So no, PTS is not the same thing as BTSX, it's a separate crypto currency.