The other fossils they found included teeth, which are taller than their ancestors' and with crowns worn flattermore signs the horses had adapted to a grazing life. Analyses of the isotopic composition of the enamel confirmed that E. woldegabrieli subsisted on grass.
"Grasses are like sandpaper," Simpson said. "They wear the teeth down and leave a characteristic signature of pits and scratches on the teeth so we can reliably reconstruct their ancient diets."
Horse expert Raymond L. Bernor, from the Laboratory of Evolutionary Biology at the Howard University College of Medicine in Washington D.C., led the fossil analysis. The bones, which remain at the National Museum of Ethiopia in Addis Ababa, Ethiopia, showed this was a significantly different animal than the horses more than 5 million years old, and those 3.5 million years old and younger. Members of the youngest group are taller and have longer noses, further adaptations to the open grasslands, the researchers say.
Members of the two paleontological projects decided to name the species in honor of WoldeGabriel, a geologist at Los Alamos National Laboratory. They want to recognize the high professional regard he's earned from peers and his many contributions in unraveling the geological complexities of the deposits in the Ethiopian Rift system where fossils of some of our oldest human ancestors have been found
WoldeGabriel, who was not involved in the analysis of the fossil horse, is the project geologist for the Middle Awash project in Ethiopia.
"Giday oversees the sedimentology, geochronology and volcanology and how the Middle Awash Valley in the Afar rift is changing shape," Simpson said. He praised WoldeGab
|Contact: Kevin Mayhood|
Case Western Reserve University