Scientists examine fossils all the time, but, every now and then, they come upon one that rewrites history.
Such is the case with the remains of a long-necked, water-dwelling reptile that lived some 250 million years ago.
Examination revealed that the Middle Triassic creature was carrying an embryo, an indicator of live birth.
That discovery counters much of what is understood about reproduction among a key reptile group that includes modern day crocodiles and birds.
Drawing by Dinghua Yang
Up until recently, it was believed its past and present members only produced young by laying eggs.
One of the researchers, Jun Liu from Hefei University of Technology China, admitted the discovery was unexpected and that, at first glance, the team thought the small specimen may have been the larger one's lunch.
Closer study revealed it was actually a developing offspring.
Liu also noted, "Further evolutionary analysis revealed the first case of live birth in such a wide group containing birds, crocodilians, dinosaurs and pterosaurs among others, and pushes back evidence of reproductive biology in the group by 50 million years."
The study involved the work of an international team of researchers, and the fossil they examined was found in southwestern China.