So I'm back working on an update for this mod, the title of the mod should really be changed to just prehistoric animals in the future since what I've been making so far has been mainly prehistoric mammal related. Still has some work to do, so I'm not sure when v1.4 will be released, but I figured I'd give you guys a preview of what's coming. I managed to figure out what I was doing wrong that was causing part names not to show up in the editor, so the next update should have all the parts properly named. In addition, so far I've made 2 new heads and a new foot:
Wolf Head and Feet:

The wolf head has the following morphs:
Golden Retriever
German Shephard
Bear
Hyaenodon
Hyena
Pachyderm Head:

This is the first head I've actually added an animation for besides opening and closing the mouth, I used the smile/frown animation slot to add trunk movement (it raises its trunk when it would be smiling, it curls its trunk in slightly when it would be frowning). It looks a bit clunky when the animation plays rapidly but generally I think it worked out pretty well.
This head also has the following morphs:
African Elephant
Asian Elephant
Woolly Mammoth
Columbian Mammoth
Mastodon
Stegodon
All of the above morphs also have submorphs of just the tusks ranging from the big mammoth style tusks like seen above to completely tuskless. Unfortunately I couldn't make all tusks available for all 6 different species, I tried to make the tusks a separate morph handle but it didn't work properly, so instead I had to merge it into the general head shape morph handle. Since there's only 30 frames of animation available, I was forced to limit what tusks each species was given, so I just went with what each species has/had in reality. So you won't be able to do African Elephants with mammoth tusks for example, but each species has multiple tusk variants (African elephant has tuskless, small tusk, average tusk, and curved tusks, for example).
For stuff that's still WIP, I have the base model for a Smilodon head made, but still need to make its textures, animations and morphs. It'll probably have morphs of modern cats and Thylacosmilus. Also might add some other mammals like rhinos, deer/antelope, horses, etc, and I've been wanting to make a toothed pterosaur head as well, but those mainly depend on how much spare time I have. At this time, I'm only guaranteeing that the Smilodon head will be made. Like I said above, I don't know when this'll be done, I had quite a bit of time over the holidays to get what I've listed so far done but now that they're over I'm back to my busy schedule.