Researchers discovered the remains of a 47 million-year-old horse that had a foal in its stomach.
The finding provides insight into the reproductive systems of the ancient animals, dubbed Eurohippus messelensis, and shows they are remarkably similar to those of modern horses, Discovery News reported.
The horse drank from a lake located in what is now Germany, but was unaware it was tainted with poisonous volcanic gas. The animal was about the size of a modern fox terrier, and had four toes on her front feet and three in the back. The process of anaerobic bacteria decaying the body actually caused It to become slowly petrified and preserved. It created a thin bacterial residue that looked like soft tissues, allowing the researchers to examine the specimen in great detail, LiveScience reported.
The quality of the fossil is exceptional," Jens Lorenz Franzen, the lead author of the study, told NBC News. "The size of the fetus and the presence of fully developed milk teeth indicate that it was close to delivery when the foal and its mother died."
The fossil was discovered by a Senckenberg Research Institute Frankfurt back in 2000, but it wasn't until 2009 that the specimen was examined with a micro X-ray by Franzen.
"It turned out this was an almost complete and articulated skeleton with a fetus," Franzen told Discovery News.
The X-ray analysis revealed a broad ligament that connected the horse's uterus to its backbone to help support the unborn foal. It also showed traces of its uterine wall, which exists today in modern horses.
The fossil was discovered at the Messel Pit fossil site, which is known for containing well-preserved fossils from the Eocene Epoch, which occurred between 36 and 57 million year ago.
"Completely preserved skeletons of fossil horses are rare," Bruce MacFadden, a professor and curator of vertebrate paleontology at the University of Florida, who was not involved in the study told Live Science."Usually, they're fragmented and the bones are all dissociated. If you find a skeleton with a preserved foal inside, that indicates exceptional preservation, which is normally not found in the fossil record."
