As soon as methods for time travel were developed, interest gathered for it's application for paleontology. Missions were incredibly expensive and quite risky too, not unlike spaceflight.
Numerous failsafes had to be built in. After all, time itself stood at stake. Thus, in case of a total critical failure, the machine will enter a damage control mode and adjust itself, it's cargo and occupants, in a way to avoid any potential damage to the timeline.
Tropical environments were on top of the list for study. Fossil preservation was very poor in those environments, so there was sure to be plenty of discoveries.
At least if it wasn't for the sudden failure of one of the machines internal components.
Probably worse fates for a paleontologist than to become the thing he has devoted his life to. Especially if it's an undiscovered species.

This one took a while to put together.