Archaeologists have discovered a 48-million-year-old horse-like fetus in the Messel pit near Frankfurt, Germany.

The discovery was made by a team led by Jens Lorenz Franzen from Senckenberg Research Institute Frankfurt, Germany and Naturhistorisches Museum Basel, Switzerland. The fetus was found in the year 2000; however, due to the quantity of samples recovered it took some years for the analysis to begin.
The recovered bones have been studied for their anatomical structure using special scanning electronic microscopy together with high-resolution X-rays.

The X-ray scanner needed to operate on the micro-scale, given that the fetus was only 12 centimeters long.

Fortunately the specimen was well-preserved with most of its bones present. The key aspect missing was the skull (here the researchers speculate that the skull had been crushed). It would seem that the mare died before giving birth and the bones of the fetus were preserved over millions of years.