Oldest known foetus found in 48-million-year-old horse fossil

A foetus discovered in a 48-million-year-old horse predecessor in Germany is the oldest known and best-preserved fossil specimen of its kind, scientists say.
The foetus of the European Eocene equoid Eurohippus messelensis was discovered at the Messel pit near Frankfurt in 2000.
Jens Lorenz Franzen from Senckenberg Research Institute Frankfurt and colleagues evaluated the bones and anatomy and used scanning electronic microscopy (SEM) and high-resolution micro-x-ray to describe the approximately 12.5 cm foetus.
The foetus appears to be well-preserved, with almost all bones present and connected, except for the skull, which appears to have been crushed.
"The foetus is the earliest and best-preserved fossil specimen of its kind," researchers wrote in the journal PLOS ONE.

The well-preserved condition of the fossil allowed the researchers to reconstruct the original appearance and position of the foetus.

They estimate that the mare may have died shortly before birth, but don't believe the death was related to birth.
The researchers also found preserved soft tissue, like the uteroplacenta and one broad uterine ligament, which may represent the earliest fossil record of the uterine system of a placental mammal.
The researchers discovered a bacterial lawn replacing the soft tissues, as is common with other specimens found in that area.
The observable details correspond largely with living mares, which suggests that the reproductive system was already highly developed during the Paleocene, and possibly even earlier.