Fossil birds with teeth discovered, had seeds in their stomachs indicating they ate fruit

[Still Waters]

In a study published in the journal Current Biology, researchers found fossilized seeds in the stomachs of one of the earliest birds. This discovery shows that these birds were eating fruits, despite a long-standing hypothesis that this species of bird feasted on fish (and more recent hypotheses it ate insects) with its incredibly strong teeth.

Longipteryx chaoyangensis lived 120 million years ago in what's now northeastern China. It's among the earliest known birds, and one of the strangest.

https://phys.org/news/2024-09-paleontologists-fossil-birds-teeth-seeds.html

[Procyon]

Maybe it ate nuts of some kind when fruit wasn't available. Those teeth could've been useful for cracking the shells. It could've used them to crack open clamshells or oysters too, perhaps? They'd thought it ate fish, but mussels and such wouldn't leave bones in the stomach if they formed a part of its diet.

It could also be some early version of the "egg tooth". A lot of birds do have a tooth at the end of their beaks when they're first born, which they use to break out of the shell. Maybe in these early birds they hadn't yet evolved to lose that tooth when they're older.