Meiofauna

"Among the grains of sand in the surf zone you will in time find... entoprocts, gastrotrichs, gnathostomulids, kinorhynchs, nematodes, nemerteans, priapulids, sipunculans, and tardigrades."

Encountered in Chapter 13 of E.O. Wilson's newest book, Half-Earth: Our Planet's Fight for Life.  It's a plea for habitat conservation and the preservation of our planet's biodiversity.  Most of the information is familiar, but for the TL;DR crowd I can highly recommend Chapter 15 ("The Best Places in the Biosphere"), for which Wilson polled "eighteen of the world's senior naturalists, each with international experience and expertise in biodiversity and ecology, and asked their opinion on the best reserves, those sheltering assemblages of notably unique and valuable species of plants, animals, and microorganisms."  The resulting compilation of about 35 locations is a joy to read.

Including this about the scrubland of southwestern Australia:

"Possessing a mild, Mediterranean-type climate and molybdenum-deficient soil that excludes species other than those adapted to the deficiency, the scrublands have evolved much like the flora of an oceanic island."

You learn something every day.