Paleontologists from Spain and the United States have discovered a new genus and species of small-bodied ape that lived about 11.6 million years ago, before the evolutionary split of humans/great apes (hominids) and gibbons (lesser apes).

The new ape species, Pliobates cataloniae, challenges current views on the last common ancestor of the two groups (extant hominoids), according to a paper published in the journal Science.

“We used to think that small apes evolved from larger-bodied apes, but Pliobates cataloniae tells us that small and large apes may have co-existed since hominoids originated,” said Dr Sergio Almécija of the George Washington University and the Autonomous University of Barcelona, a team member and a co-author of the paper.

“Alternatively, Pliobates cataloniae might indicate that great apes evolved from gibbon-size ape ancestors.”

The incomplete skeleton of Pliobates cataloniae was found in 2011 in the Vallès-Penedès Basin, northeast Iberian Peninsula, and was composed of 70 fossil remains.

“The fossil remains belong to an adult female that weighed between 4 and 5 kg, consumed soft fruits and moved through the forest canopy by climbing and suspending below branches,” the paleontologists said.

The discovery of Pliobates cataloniae fills a gap in the fossil record, giving scientists another piece of information about the evolution of great and small apes.

They previously thought that great apes were present before small apes, mainly due to the lack of small apes and ancient gibbons in the fossil record. The newly-discovered extinct ape has forced them to consider the role that small apes played in hominoid evolution.

“These remains clearly belong to an ape, but they are so small,” Dr Almécija said.

“Then we realized, maybe we are looking at this the wrong way. Maybe some early ape ancestors were smaller than we thought.”

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David M. Alba et al. 2015. Miocene small-bodied ape from Eurasia sheds light on hominoid evolution. Science, vol. 350, no. 6260; doi: 10.1126/science.aab2625