麻豆传媒

80 million years before the first birds, a dinosaur-like creature had a surprisingly bird-like skull. This hints that the animal begged for food from its parents, like baby birds today, and that even early dinosaurs cared for their young 鈥� but not everyone is convinced.

Silesaurus opolensis was . It was lightly built, about 2.3 metres long from nose to tail, and may have had a distinctive beaked jaw. Most researchers think it was a close relative of dinosaurs: a proto-dinosaur or 鈥渄inosauromorph鈥�.

To find out about their lifestyle, at Uppsala University in Sweden and his colleagues studied three S. opolensis braincases. One feature stood out: two bony projections near the back, the paroccipital processes. They were orientated in the same way as in birds.

That鈥檚 odd, says Niedz虂wiedzki. Existing evidence suggested this feature only evolved tens of millions of years later, in the theropods: the dinosaurs that gave rise to birds.

In modern birds, this feature allows certain neck muscles to grow large and powerful. These neck muscles give a baby bird the power to break out of its egg, and help it .

Niedz虂wiedzki suggests young S. opolensis did the same. 鈥淛uvenile Silesaurus might have displayed begging behaviour,鈥� he says. This would imply the species cared for its young.

A knack for begging?

Our only evidence for parental care in dinosaurs is from much later. Some theropods that lived near the end of the dinosaur era seem to have died and been fossilised while brooding eggs. Other studies suggest these species .

But we don鈥檛 know if early dinosaurs did likewise. We know , and crocodiles are birds鈥� nearest living relatives. So it鈥檚 been argued that , which lived before even Silesaurus. .

In some ways the Silesaurus braincase does look more bird-like than reptile-like, says at the University of Edinburgh, UK. 鈥淭his makes sense, as Silesaurus is a very ancient member of the lineage that eventually produced birds.鈥� If Silesaurus were alive today, we might see it as more bird-like than reptile-like.

However, it is less clear that it cared for its young. Using a single feature to argue that Silesaurus was capable of juvenile begging is an 鈥渋nterpretation too far鈥�, says at the University of Lincoln, UK.