For almost 250 years, excavations in the limestone quarries of southern Germany have slowly revealed a secret: the remains of hundreds of pterosaurs.

Now, pterosaurs usually don’t fossilize well their thin, hollow bones were often too delicate to survive intact in the fossil record.

So while they once ruled the skies, these flying reptiles barely left a trace that they even existed at all outside of just a few key fossil sites.

At the Solnhofen formation in Germany, though, over 500 fossils of 15 pterosaur species have been found, beginning in 1784 with the very first pterosaur ever described.

They date back to the Late Jurassic Period, around 150 million years ago, when the region was a tropical archipelago dotted with shallow lagoons encircled by reefs of coral and sponges.

These lagoons formed a pterosaur fossil factory preserving many of them in incredible detail right down to the membraned wings and tufts of fluff.

But the Solnhofen formation might be hiding a dark secret, one that’s been massively distorting our view of who was living and dying there, and why they left so much evidence behind.

Because it turns out that this treasure trove of pterosaur fossils may only exist thanks to a literal perfect storm.

The Solnhofen formation is what’s known in the field of paleontology as a lagersätte or storage-place.’ It’s a term used to describe fossil sites that have exceptional preservation.

Each one is kind of like a geologic miracle, because fossilization is usually incredibly rare.

So lagersätten represent a lucky few places where the right conditions came together to fossilize species in large numbers, or in amazing detail, or both.

They’re often our best windows into ancient life.

But these amazing sites can in some ways be a bit of a curse.

Because what life those windows are showing us might be massively deceptive.

Take the La Brea Tar pits for example, a lagersätte in Los Angeles.

Around 90% of the ancient mammals recovered from the tar pits are carnivores, including thousands of direwolves and saber-tooth cats.

So, should we assume that predators were actually 90% of the mammals on the landscape?

No, because that would be very weird carnivores are often the rare ones in an ecosystem, by a landslide.

Instead, it turns out that the tar pits are inherently biased toward them.

As herbivores got stuck in the tar and became exhausted, predators flocked there in search of an easy meal, only to themselves become stuck in even greater numbers.

In other words, the fossil record of who died in a place isn't always a perfect reflection of who lived in a place.

And until we really understand how and why a fossil site formed, it’s hard to trust it.

So paleontologists are constantly asking: Does a site accurately reflect the ecosystem that existed there?

Or is there bias involved in who fossilized and who didn't?

Unlike La Brea, though, other lagersätten, including Solnhofen, haven’t revealed their specific biases so easily.

And Solnhofen is especially strange.

Not just because it’s so unusually rich in detailed, complete pterosaur fossils, but also because of the kinds of pterosaurs we see there.

Normally, you’d expect bigger individuals and species with more robust skeletons to fossilize better, especially in fragile groups like pterosaurs.

And in the few other good pterosaur fossil sites we do have elsewhere, that’s pretty much what we see: more larger, older specimens, and fewer smaller, younger ones.

But the Solnhofen pterosaurs seem to skew the opposite way.

There are many well-preserved small pterosaurs - including lots of juveniles.

And only very rarely do we see some fragmentary evidence of anything reaching or exceeding 2 meters in wingspan.

So, for a long time, many scientists simply assumed that this was just a reflection of the pterosaur community that lived there It seemed like these lagoon ecosystems were a hotspot for diverse species of small pterosaurs and their young.

And larger species were rare both here and possibly in the Jurassic overall.

If you take the Solnofen pterosaur fossils at face value, then that is what they suggest.

But in 2025, a team of researchers fully turned this assumption on its head, saying that what we see at Solnhofen isn't actually a typical snapshot of the species that lived there Instead, it's a massively biased collection of pterosaurs brought together mainly by one shared factor: they fell victim to catastrophic storms.

But how can the fossil record capture ancient gusts of winds that blew 150 million years ago?

Well, the researchers discovered some intriguing evidence in two tiny Solnhofen pterosaurs, named Lucky and Lucky II.

They belong to a small species called Pterodactylus antiquus, known to have wingspans reaching only about a meter when fully grown.

And because Lucky and Lucky II are just weeks old at most, their wingspans measure under 22cm, making them some of the smallest pterosaurs known from the entire fossil record.

By examining them under UV light, the researchers found that these two pterosaur babies have almost identical injuries.

Both had clean and slanted wing fractures - in Lucky’s left humerus, and in Lucky II’s right.

And the injuries don’t seem to have been caused by attacks from predators or collisions with objects both of which would have left other forms of damage, as well.

Instead, they seem to be the result of powerful twisting forces that strained and snapped their fragile wings during flight.

And they’re eerily similar to injuries seen in the juveniles of modern flyers like birds and bats during strong storm winds.

Beyond dooming Lucky and Lucky 2, the researchers argued that most of the Solnhofen pterosaurs were probably also storm victims.

See, while none of the others have the same injuries, we wouldn’t necessarily expect them to.

Because when groups of modern birds are killed by storms, we only see widespread injuries when these events happen over land.

For example, as the birds are flung into trees and rocks or fall to the ground.

But when deadly storms happen over marine environments, only a small proportion die with visible skeletal injuries to tell the tale - most simply become exhausted and drown.

So the tiny identical fractures of Lucky and Lucky II may be rare evidence of much larger mass-mortality events that killed hundreds or even thousands of pterosaurs each time.

Now, if catastrophic storms were responsible for the pterosaurs at Solnhofen, that may explain many of the strange things about fossils here, including the fact that this lagerstatte even exists.

The storms didn’t just kill these pterosaurs, they also brought with them the ideal conditions to preserve their corpses before they could be torn apart by scavengers, or decay and crumble away.

When dead pterosaurs sank to the bottom of the lagoon floor, they were rapidly buried in mud flows stirred up by the powerful wind and waves.

And that rapid burial in fine sediment almost immediately after death is probably the main reason that so many incredible pterosaur fossils formed there in the first place.

But it also potentially explains why the pterosaur fossils there are dominated by small and young individuals, too.

For one, bigger, older pterosaurs would have been able to escape or ride out the storms.

And even for those that were killed, their larger and more buoyant bodies would generally float on the surface of the water.

Being on the surface long enough would have increased their chances of being scavenged or of decomposing eventually falling to the lagoon floor in the form of isolated fragments.

Which is probably why we have no complete and well-preserved evidence of large pterosaurs from Solnhofen Not because they weren’t around, but because they just didn’t have the same chance to settle intact and become rapidly buried that the smaller pterosaurs did.

What’s more, the Solnhofen pterosaurs were probably not even a single community.

They may have died together there, but that doesn’t mean that they lived together there.

Instead, the storms turned the site into a deathtrap.

Strong winds swept up diverse species from distant habitats across the island chain and flung them out over the lagoons.

This gave the impression of a single coexisting community of over 15 distinct species in this ecosystem.

But it's actually a jumble of individuals that just happened to be caught up in the same catastrophes, many of whom weren’t native to the lagoons at all.

Solnhofen may be one of our single richest and most influential sources of information on pterosaurs ever found, but almost nothing about it is exactly as it seems.

And it points to a bigger, kind of ironic problem in paleontology, known in the field as the Lagerstatte effect.

The fewer fossils and fossil sites we have for an extinct group, the more misleading the ones we do have can be.

Without a good frame of reference, it’s not always clear if they’re giving us a typical, unbiased glimpse into deep time.

Maybe what we’re seeing has been distorted by forces we don’t even realize were involved.

And for pterosaurs in particular, whose fossils are so rare, the lagerstatte effect clouds basic aspects of their ecology and evolution more than almost any other ancient vertebrates From their diversity, to their sizes, to how and where they lived and died.

And if it wasn’t for the unfortunate Luckys, our understanding of pterosaurs might have been forever blown off-course.