Cretaceous birds were thought to have small bills, except this one

Given the unusual focus on turkeys this week, let’s talk about dinosaurs. Today’s birds are, of course, the descendants of the only branch of the dinosaur tree that survived the mass extinction of the late Cretaceous period. In the happy days of the dinosaurs, early birds were somewhat different, still retaining their front teeth and legs amid some more subtle anatomical differences with their modern descendant. A new fossil find reveals an unexpected bird from that period, one with a huge beak resembling a toucan.

The fossil, called Falcatakely forsterae, comes from the late Cretaceous rocks in Madagascar. Many of the earliest bird fossils we’ve discovered so far come from older early Cretaceous rocks in China, with the period between then and the late Cretaceous extinction plus a question mark. The new fossil is a well-preserved head of a raven-sized bird with an extraordinarily long, tall and narrow beak.

Early Chinese bird fossils don’t show much diversity in beak shape. This is a great contrast to modern birds, which have a wild variety of beak shapes befitting their many different ecological niches. Pelicans, woodpeckers and parrots all have very different diets that require a beak that is suitable for work. It was thought that widened beaks would not be possible until an anatomical shift in parts of the skull had occurred, meaning early birds were simply limited. But the new discovery shows that it wasn’t entirely true. This species could have inhabited an ecological niche that was empty after extinction, until a more modern bird re-entered it much later.

The researchers used 3D imaging to accurately determine the size of each anatomical component. This showed some differences from non-bird theropod dinosaurs or more modern birds. The fossil creature may have had an overall beak shape similar to some modern birds, but this is despite the fact that the underlying structure is different.

There are some teeth visible near the tip of the beak rather than further back, like its relatives. And the height of the upper beak is achieved through a very large jawbone (brown in the image above), where other fossilized species from this period had a thin V-shaped bone. Modern birds, on the other hand, have tiny maxillary bones and beaks supported by a large premaxillary bone (green near the tip of the beak in the image above).

If there is one strange Cretaceous bird, there may be others, adding more diversity to the Cretaceous collection. The find also raises interesting questions about the evolution of skull structure and beak shape, as modern anatomy was apparently not required for a large beak of that shape. This takes a simple story and complicates it a bit, as the same form has evolved in different times and ways.

Alright then. The surprising fossils are even more fun than the unsurprising ones, further enriching our image of the past.

Nature, 2020. DOI: 10.1038 / s41586-020-2945-x (About DOI).