Anyone Know A Little Biogeography?

[tiger7]

First post here, mainly because I've never had this much trouble figuring out an answer.

 

Here's what I'm stuck on:

 

What is a taxa that is either a taxonomic or biogeographic relict but not both?

 

I'm pretty sure this is going to be part of an essay question on my final later this week, and I've been stumped for a few days now. I know examples that are considered both, and there are some that would technically work, but we cannot use (ginkgo, humans).

 

Any tips on where to look, or certain things to look for would be appreciated.

 

Thanks in advance.

[Mokele]

Crocodiles. Worldwide distribution, but now there's only 23 species (give or take, depending on the study) with highly limited ecological diversity, compared to a rich paleontological history with everything from herbivores to massive oceanic predators to duck-like sifters.