I couldn't find a working Ichthysaur npc so I decided to take a crack at my own. Their attacks do 50 damage and they have 500 health. They are also faster than the player.
If you wish to change the amount of health or damage they have you can open: \Ichthyosaur\lua\autorun\hlr_concommands.lua and change the data to what you wish.
Put the "Ichthyosaur" folder in your "addons" folder.
*Edit: I also forgot to mention that they don't have a death animation because, I couldn't find one.