The Archaeologist Villager is a special kind of villagers from this mod that can spawn in villages. They can sell you items from the mod for emeralds. Something to note is that they are very, very difficult to find naturally.
Archaeologist Villager looks like a villager that wears white clothing, brown belts with a golden belt buckles and a pair of brown pants. Nothing really out of the ordinary.
They act just like any other villagers - they are passive to anything that attacks them, walks around at the daytime, hides inside any available building at night time, will run away from zombies, can talk to other villagers and will trade with you when right-clicked. They can trade Bio-fossils, Stone Javelins, Essences of chickens, Dinosaur meat, and other items from the mod.