MAMMALS IN TIME

from the first synapsid to us · 320 million years on one axis

Built as a memo rather than a table: the thing worth hanging it up for reads across the room, with the full reference in smaller type below it.

Three sizes in one archive — from a sheet on the fridge to a poster on the wall.

Formats: A4 · A3 · A2
What you get: Print-ready PDFs, one per size, with every letterform converted to outlines — nothing to install, nothing to shift.
Subject: science · school · reference · classroom

A bar begins at the age of the oldest known find, hence the "≈". A cross marks extinction. The dinosaur bar is shown for comparison, not as part of the mammals. Period boundaries follow the ICS scale.

DIMETRODON IS NOT A DINOSAUR — IT IS YOUR RELATIVE

The sail-backed reptile that comes in every box of toy dinosaurs is not a dinosaur at all. It is a synapsid — from the same branch of the amniotes as you — and is closer kin to you than to any tyrannosaur.

The gap in time is as sharp as the gap in kinship: Dimetrodon died out roughly forty million years before the first dinosaur appeared. Seeing the two together was as impossible as seeing a mammoth beside a trilobite.

A synapsid is easy to spot: one temporal opening behind the eye in the skull, not two. It is the same feature that still separates you from a lizard — in humans the opening is simply bridged by the cheekbone.

On the sheet

A bar begins at the age of the oldest known find, hence the "≈". A cross marks extinction. The dinosaur bar is shown for comparison, not as part of the mammals. Period boundaries follow the ICS scale.
Colour carries meaning, but meaning never rests on colour alone — the sheet reads in black and white.
Nothing about how it was made: the sheet carries only what the reader needs.

Printing

Three sizes in the archive: A4 — 210×297 mm, A3 — 297×420 mm, A2 — 420×594 mm.
All text is converted to outlines. No fonts to install, and nothing shifts on another machine.
White background and sparing fills — it prints on a home printer without draining the cartridge.
Margins of at least 10 mm: a home printer cannot print to the edge.
No stroke thinner than 0.3 mm, so nothing disappears in print.

Why the numbers can be trusted. Every countable number here is computed from data rather than typed in, and the sheet must pass 7 independent checks before it is allowed to build — how many items there are, the order they come in, and the claim in the highlighted box itself. If one fails, there is no file.

MAMMALS IN TIME

DIMETRODON IS NOT A DINOSAUR — IT IS YOUR RELATIVE

On the sheet

Printing

More like this

THE VERTICAL PLANET

VERTEBRATES IN TIME

BASIC PHYSICS FORMULAS

ANIMALS