figured it out, i think. i have two mods installed that both add anomalocaris and hallucigenia, so i ended up with two different files trying to define CREATURE:HALLUCIGENIA and i guess that just broke everything else

Some of the fun of presteam DF was raws duping, which you may have experienced, I was hoping that the workshop integration meant that some error checking was involved. As otherwise last time I played I had to merge mods manually to get the ones I wanted.

Originally posted by Lord Nich:

Some of the fun of presteam DF was raws duping, which you may have experienced, I was hoping that the workshop integration meant that some error checking was involved. As otherwise last time I played I had to merge mods manually to get the ones I wanted.

yeah, it's real funny stuff (and looking back on it, that was definitely my problem). kinda unfortunate that it can just Happen when you're not expecting it, i would've expected people to use unique identifiers for their creatures to help prevent this sorta thing... it's what most modders do for other games i'm familiar with, and i'm sure it'd be useful here.
one particularly funny side effect of this one, though, was forgotten beasts being available at embark for a mere 1 point each. i'm not sure what kind of forgotten beasts they were, or if they were friendly, but it was definitely interesting to see.