I'm not exactly smart, but I got a barryonyx just for cave runs, and lava cave or north east cave give tons of chitin, my slightly boosted server yeildes about 1-1 1/2 k chitin, and if you go northeast cave then you can also raid carbo island for pulmonos. Happy arking!
If 7 want alot of chiten kill matisis no matter what u use youll usually get at least a hundred. If you use a megatherium u got almost 1000 with a tame. U got a breed one your looking at 1500 each mantis