Scientists Solve the Mystery of These Strange South American Mammals

Scientists have resolved a nearly 200-year-old mystery surrounding a group of mammals in South America. Scientists have discovered that ungulates, hooved mammals that disappeared only 10,000 years ago, are actually related to mammals like horses rather than elephants and other species with ties to Africa.

"Although the bones of these animals had been studied for over 180 years, no clear picture of their origins had been reached," said Ian Barnes, one of the researchers, in a news release. "Our analyses began by investigating ancient DNA to try to resolve the problem."

Fitting South American ungulates into the mammalian family tree has been a problem for years. Anatomically, these animals have strange features that can be found in a huge variety of unrelated species living all over the globe.

In order to better understand these animals, the researchers looked at ancient fossils. They couldn't study the DNA of the fossils, since the genetic material didn't survive the warm, wet conditions of South America. Instead, the scientists analyzed collagen. The chemical structure of the amino acids that make up this protein is ultimately dictated by specific coding sequences in the organism's DNA. Because of this key relationship, amino acid compositions of the same protein in different species can be analyzed and compared, providing insight into how closely the species are related.

"By selecting only the very best preserved bone specimens and with various improvements in proteomic analysis, we were able to obtain roughly 90 percent of the collagen sequence for both species," said Frido Welker, lead author of the new study. "This opens the way for various other applications in paleontology and paleoanthropology, which we are currently exploring."

The findings reveal that ungulates are most closely related to perissodactyls, the group that contains horses, rhinos and tapirs. The scientists also believe that the South American ungulates actually came from North America more than 60 million years ago.

The findings are published in the journal Nature.

For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).