This episode was originally released four years ago in February of 2021 into what feels like a very

different world. It's called the air and the sea and the land. This is the memory palace. I'm

Nate DeMao. During the 300 million or so years of the Paleozoic era, life thrived, largely in the oceans,

though later periods within it did see the first development of terrestrial life, your ferns,

your extra large dragonflies. But the ocean was where the action was.

Protocrustations and arthropods,

and evolution's first stabs at a workable fish.

The apex predators were the nautaloids.

We still have them today.

You may have seen them at the aquarium in a darkened tank,

cast in an eerie blue light to simulate their deep sea homes.

They are so strange, like ambulatory ramshorns, with a peculiar white eye and a beard of tentacles.

They are among the most alien-looking creatures we have, a remnant of a time when the Earth was a very

different place.

There are six species of nautilodes now.

But paleontologists tell us that in the Paleozoic, there were many more, varying significantly, some tiny, some gargantuan relatively as far as mollusks go.

Some in that spiral shape familiar from natural history museums or other gift shops.

Others oblong or dagger-like.

Depending on whatever conditions, whatever available resources,

whatever competitive necessity shaped their evolution a quarter of a billion years ago,

some 2,500 different species.

Lewis Pernell noticed some were missing.

...