Did the great apes evolve later than we thought? Researchers say 11.9 million year old fossil could rewrite evolutionary history
- Straighter finger bones could mean great apes didn't evolve, or behave, the way scientists first thought
- The fossils are thought to be from the last common ancestor of today's great apes
Experts studying an ape
skeleton that lived around 11.9 million years ago believe they may have found contradictions between how scientists think apes evolved, and how this early primate would have behaved.
An anatomy expert from the University of Missouri found that the pelvis of the Pierolapithecus catalaunicus ape was wider than apes that lived later, suggesting it used its forelimbs more and therefore needed better lateral balance and stability.
Yet the ape's finger bones were straighter than it ancestors, which indicates it didn't swing or hang as much as modern day apes.
An anatomy expert from the University of Missouri claims the large pelvis (circled) of the Pierolapithecus catalaunicus with the straighter fingers suggest it moved in a more upright position than first thought
LESSER APES VERSUS GREAT APES
Apes are distinct from other primates such as monkeys mainly because apes don't have tails.
There are 16 species of ape split into two families: hominidae (great apes) and hylobatidae (lesser apes).
The great apes include humans, chimps, gorillas and orangutans.
Lesser apes are gibbons and siamangs.
The two families are closely related scientifically and share several common traits, but also have marked differences.
The most obvious difference between greater and lesser apes is size.
The smallest great apes are bonobo chimps which grow to between three and four feet in height and weigh between 59 to 134 pounds.
The lesser siamang ape, grows to between two and three feet in height, and weighs around 24lbs.
All lesser apes have very long thin arms that are out of proportion with their legs.
In great apes, especially gorillas and humans, the different between the length of the arms and legs are less pronounced.
Great apes also tend to have larger brain cases and more prominent facial features.
This contradiction suggests the great apes didn't develop curved fingers until much later.
Meaning evolution of the great apes started years after scientists believed.
Spanish scientists found the fossils of the previously undiscovered ape in 2002.
In 2004 it was confirmed to be an entirely new genes and species - the Pierolapithecus catalaunicus in.
Ashley Hammond, a Life Sciences Fellow in the department of pathology and anatomical sciences at the University of Missouri, used a tabletop laser scanner, attached to a turntable to capture detailed surface images of the fossils.
This provided her with a 3D model to compare the Pierolapithecus pelvis anatomy to living species.
Hammond said the ilium, the largest bone in the pelvis, of the Pierolapithecus catalaunicus is wider than that of Proconsul nyanzae, a more primitive ape that lived approximately 18 million years ago.
This wider pelvis may be related to the ape's greater lateral balance and stability which it would have needed as it moved using its forelimbs.
However, the fingers of the Pierolapithecus catalaunicus are unlike those of modern great apes, indicating that great apes may have evolved differently than scientists originally hypothesized.
A tabletop laser scanner attached to a turntable was used to capture detailed surface images of the fossils. Anatomy expert Hammond could then make 3D models and compare them to the bones of modern day species
Hammond said: 'Pierolapithecus catalaunicus seemed to use a lot of upright behaviors such as vertical climbing, but not the fully suspensory behaviors we see in great apes alive today.'
'Today, great apes such as chimpanzees, orangutans, bonobos and gorillas use forelimb-dominated behaviors to swing below branches.
'But Pierolapithecus catalaunicus didn't have the long, curved finger bones needed for suspension, so those behaviors evolved more recently.'
Hammond suggests researchers need to continue searching for fossils to further explain the evolution of the great apes in Africa.
'Contrary to popular belief, we're not looking for a missing link'
'We have different pieces of the evolutionary puzzle and big gaps between points in time and fossil species.
'We need to continue fieldwork to identify more fossils and determine how the species are related and how they lived. Ultimately, everything is connected.'
The ilium, the largest bone in the pelvis of the Pierolapithecus catalaunicus is wider than that of the Proconsul nyanzae, a more primitive ape that lived around 18 million years ago. This suggests evolution began earlier than first thought