The famous feathered dinosaur archaeopteryx seems to have had a penchant for fossilizing in painful positions, with its head cranked backward at a severe angle. The contorted posture is so common in dinosaur fossils that it has its own name: opisthotonus, from the Greek “tonos,” meaning tightening, and “opistho,” behind.

Since the 1920s, paleontologists have debated how these dinosaurs came to have such grotesque final resting positions. Some theorized that water currents moved the bones into formation, or that the muscle contractions of rigor mortis pulled the head backward. Others thought the animals must have died in pain.

New research proposes a simpler explanation.

In a paper published last month in the journal Palaeobiodiversity and Palaeoenvironments, Achim G. Reisdorf of the University of Basel in Switzerland writes that the trouble with the death-throe hypothesis is that carcasses are flexible. To fossilize in the traumatic death position, a carcass would have to be quickly buried in the exact spot where it died, without any transportation.

But that is unlikely, Mr. Reisdorf wrote. Many of the dinosaurs found in opisthotonic posture are land animals that fell into sediment at the bottom of bodies of water, and probably had to settle before reaching their final resting place.