the.com/microfauna

means The microscopic animals—nematodes, mites, protozoa, rotifers and the like—living in soil, water, or on other organisms, usually invisible without a microscope.

from Built from Greek *mikros* ('small') plus *fauna*, the Latin name of Fauna, the Roman goddess of animals and wild nature. Fauna's name was borrowed by 18th-century naturalists as a general term for 'the animal life of a region,' pairing naturally with 'flora' for plant life. Tack on 'micro-' and you get a word coined simply to name the vast, teeming scale of animal life too small to see — a linguistic afterthought for creatures that are anything but.