The Solnhofen site is famous for the exquisite detail of its fossils. This is because the limestone was originally the muddy floor of a series of peculiar lagoons, with a high amount of salt and almost no oxygen at its bottom. This prevented the proliferation of life at the lowest levels, including scavengers and the bacteria responsible for decomposing carcasses, allowing many organisms that fell to the bottom to be delicately preserved.
Aspidorhynchus was about 2 ft (60cm) long and looked like a cross between a swordfish and a gar. With a slender body adapted to quick acceleration, it was a swift predator that may have used its sharp snout to stun or pierce its prey. Meanwhile, the eagle-sized Rhamphohynchus probably lived much like a coastal bird, flying over the waters and preying on small fish swimming near the surface.
Paleontologists aren’t exactly sure how the encounter went down, but a possible scenario is that the pterosaur was flying low and caught the Leptolepides that was found inside its gullet. While it was swallowing its meal, the Aspidorhynchus charged, intending to wound or stun the pterosaur. Instead, the attacker got its face ensnared in the pterosaur’s membranous wing. With the two locked together, the pterosaur couldn’t take off and the fish wasn’t able to properly swim away, making the two sink to the bottom.
Thus, while the air-breathing pterosaur drowned, the fish also suffocated by being dragged down to the toxic and oxygen-deprived waters. Undisturbed, the two bodies got buried by sediment and eventually fossilized.
In fact, four other fossils of Aspidorhynchus in association with Rhamphohynchus have been found around the same region. But according to researchers, this particular one indicates that the pterosaur was alive at the time of the attack instead of being scavenged, due to the presence of a yet-undigested meal in its throat. The number of fossils depicting these fights is evidence that it was probably a very common behavior instead of a freak incident: the fishing pterosaurs needed to keep an eye out to avoid becoming food for bigger fish.
Read the original research in PLOS One.