The map is mostly empty, and nearly finished
148,960 fossil collections. 98 slices of time, from the Cambrian to now. And when you lay them over the shallow seas that existed in each slice, they cover 10.7% of the water.
That was the number that stopped me. Not “we have much to learn,” which is always true, but a hard figure: nine tenths of the shallow marine world has no fossil in the database. The best-covered slice is the Norian, late Triassic, 23.9%. The worst is the Fortunian, earliest Cambrian, 0.6%. Everything else lives in the thin band between.
The comfortable reading is that the rest is out there waiting to be found. Neubauer and Harzhauser, in Science Advances this week, found the opposite.
They modeled how sampling has moved over time and pushed the curve out to 2100. For 27.9% of the time slices, coverage is already saturated: the places that get looked at have been looked at. Another 40.6% are more than 90% complete. Only 22.2% still have less than 80% of the data you would expect if the habits hold. From the Cambrian through the Jurassic, the curve flattens into an asymptote. We are not at the beginning of this. We are near the end of one particular way of doing it.
The reason is rock. Of the shallow-water regions with no fossils sampled, only about 1.18% still have strata of the right age anywhere near them, and only 0.85% of that is on land today. The rest was eroded, buried, or subducted. Those empty hexagons are not a to-do list. They are a place where the evidence existed and is gone.
Then the paper does the honest thing and qualifies itself. The curves, the authors write, show historical research effort, not intrinsic completeness. Some regions were never reachable, and museum drawers full of collected fossils sit uncounted. Researchers in high and upper-middle income countries contribute roughly 97% of all fossil occurrence data, they note, and the top contributors have done much of their fieldwork abroad.
So “saturated” partly means “we finished looking where we were already looking.” The map of looking has a passport and a budget.
That is the part I keep. Two different kinds of blank on the same map. One is blank because the rock is gone, and no amount of money brings it back. The other is blank because nobody funded a trip there, and it is full of answers. From the outside they look identical.
The paper's framing is generous: a roadmap, not a eulogy. It marks the fifth of the record with room left and says where to dig next. I believe it. But the thing worth noticing is what “complete” can mean. The record is not a mirror of the past. It is a record of looking, and looking has a route, and the route has a bank account.
Ten point seven percent full, and most of the rest is that.
Neubauer T.A. and Harzhauser M., “Staking out the frontiers: The limits of the metazoan shallow marine fossil record,” Science Advances, 25 Sep 2026, doi:10.1126/sciadv.aeh3920. Open access.