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A bizarre bird from the Mesozoic Era had a small, scythe-like beak with one tooth at its tip. Its fossil was found in Madagascar and hints at a lost world of ancient birds that paleontologists are only just starting to uncover.

Measuring less than 9 centimetres and sporting a curved, deep bill, the bird would have looked a bit like a tiny toucan. “When I first saw a photo of the skull, I thought I was looking at a modern-day toucan that was somehow encased in concrete,” says Steven Brusatte at the University of Edinburgh in the UK, who wasn’t involved in the study of the fossil.

The skull of this bird, called Falcatakely forsterae, was preserved in rock between 66 and 72 million years ago.

The fossil was discovered in a block of stone quarried out of a rich fossil spot in Madagascar. In addition to some big dinosaur bones, the quarry where Falcatakely was found also yielded some small bird bones, says Patrick O’Connor at Ohio University.

He and his team wrapped the block in plaster for later study. When it was CT-scanned at the lab, the researchers saw a skull unlike any found before.

Most prehistoric birds, like their modern counterparts, were small and had delicate, hollow bones. The harshness of the fossilisation process destroyed more ancient birds than preserved them. Yet when conditions were just right, exceptional specimens like Falcatakely were locked in stone.

The fossil is paper-thin in places, but the beak, parts of the upper jaw and eye socket were preserved well enough to provide a detailed look at the bird’s profile. The bones mark Falcatakely as belonging to an extinct group of birds called enantiornithines that thrived during the Cretaceous Period.

When the bird was alive, Falcatakely shared its relatively dry habitat with herbivorous, pig-like crocodiles, carnivorous, stubby-armed dinosaurs and badger-sized mammals. Falcatakely fits that oddball menagerie, the weirdness of which was probably spurred by Madagascar’s isolation after the island split off from India 88 million years ago

Alan Turner at Stony Brook University in New York says Falcatakely’s resemblance to modern-day toucans is unexpected, and it is an example of convergent evolution – when unrelated organisms evolve the same trait independently.

In living birds, the upper part of the beak is made up of a single bone called the premaxilla, but early birds from the dinosaur era had beaks made up of two bones. Falcatakely had the primitive arrangement but a modern shape, which Brusatte says “shows that, over millions of years, distantly related birds can evolve similar beak shapes using completely different bone arrangements”.

That Falcatakely is unlike any other Mesozoic bird known so far hints that there are other unusual avians out there. “A species like Falcatakley does provide the tantalizing possibility of a greater diversity of form that remains to be discovered,” says Brusatte.