A jaw bone discovered in Egypt is changing the way scientists think about the origins of the ape family tree. The specimen, which is thought to be about 17 or 18 million years old, was found in the Wadi Moghra region of northern Egypt. According to the researchers that worked on it, it could help fill a long-standing gap in the understanding of the evolution of modern-day apes.
The species has been named Masripithecus moghraensis. The description of the new species has been published in the journal Science by a research team from Mansoura University Vertebrate Paleontology Center and the University of Southern California. As stated in the study that published this new species, this is the first time that a certain type of fossil ape has been described from North Africa.
This discovery is significant because, for many years, the fossil record from North Africa during the Early Miocene contained only fossils belonging to monkeys, and no apes. Therefore, the focus of many researchers has been East Africa to understand where modern apes might have evolved. Although this new fossil provides only one additional specimen to the existing fossil record, it does reinforce the existence of apes further north than previously thought.
“We have spent five years looking for this type of fossil,” said Hesham Sallam, a paleontologist with Mansoura University and the senior author on the paper. “When you look closely at the evolution of the early ape family tree, there was clearly something missing, and we have found that lost connection in North Africa.”
The fossil material is very incomplete, but not insignificant. The pieces included a portion of the lower jaw and part of the lower jaw bone that were recovered together from the Moghra Formation of Egypt. This region is known to produce many different types of vertebrate remains. Based on where the items were found together, and the fact that they all contain the same elements, the researchers believe these three parts represent a single creature.
What really stands out most is Masripithecus‘s unique tooth and jaw structure. Its jawline is very strong and robust, and it has some of the largest canines and premolars of an extinct ape. It has molars with rounded cusps and a very strong surface texture. There is little structure resembling that seen in some of the other early apes of this group. In addition, it has equal length in both the second and third molars. This separates it from other hominoids of this period. Those hominoids have so far been discovered only as jaw pieces.
All of these anatomical features are indicative of a versatile diet. The way this team interprets the teeth and jaws indicates that Masripithecus had a predominantly fruit-based diet. However, it could also eat hard foods such as nuts and seeds. This means that the researchers believe that the chewing apparatus and anatomy are consistent with the ability to eat a more versatile diet. According to Shorouq Al-Ashqar from the Mansoura University Vertebrate Paleontology Centre, and the paper’s lead researcher, “this adaptability may explain why Masripithecus was successful during an era of increasing seasonality in northern Africa and Arabia due to climate change.”
The study suggests that there is more to Masripithecus than just an additional member of the ape family.
To determine how Masripithecus fits in, the researchers performed Bayesian analyses using a combination of fossil data, extant ape genetic data, and the geological age of the fossilized specimens. The Bayesian analysis places Masripithecus closer to living apes than any other sampled Early Miocene ape species from East Africa.
There remains some uncertainty over the placement of parts of the hominoid family tree. The research paper, referring to these placements, makes note of this uncertainty. The posterior probability of the placement of Masripithecus within the crown hominoid clade was moderate (0.6). Support values for some portions of the stem lineage were lower than 0.5. In addition, the authors note uncertainty around a previously examined Moghra humerus that may or may not belong to Masripithecus. Currently, they cannot eliminate either possibility as viable.
However, their overall biogeographic analysis indicates that they are pointing in an exciting direction. The research reconstructs early stem and crown hominoid nodes as Occidental. It suggests that there may be greater support for the origin of crown Hominoidea in Northern Occidental regions, the Levant, or the Eastern Mediterranean. Low probabilities exist for Eastern Africa.
That finding shifts even the views of one of the co-authors, who had previously held a strong belief that East Africa was likely to be the location where the last common ancestor of all extant apes existed. “Because of the new data and our new analyses of hominoid phylogeny and biogeography, that hypothesis is being strongly challenged. This new estimate of likelihood does not depend on Masripithecus, but it is certainly consistent with the included critique,” says Erik Seiffert, a paleontologist from the University of Southern California.
The timing of migration out of Northern Africa and Arabia is equally important. During the Early Miocene, Northern Africa and Arabia were in a geographic position that allowed for movement toward Asia. Both the African and Arabian plates were undergoing northward shifts at that time. In addition, significant shifts in global sea level resulted in periodic reduction of marine barriers to migration. This created corridors for migration.
Under this scenario, Masripithecus is less of an isolated anomaly and more a possible clue. The authors contend that apes in Northeastern Africa and the Arabian Peninsula may have been particularly well positioned to migrate into Eurasia at the same time that land connections were becoming available. A further point of note is Heliopithecus leakeyi from Eastern Saudi Arabia. This species is a potential representative of another lineage of apes. Comparison of the fossils is not yet possible due to a lack of overlapping material.
Another aspect of this paper’s findings is the issue of absence as much as presence. The fossil record is not evenly distributed. East Africa has provided a large number of Miocene ape fossils. Meanwhile, much of Afro-Arabia remains poorly represented in the fossil record. This imbalance likely contributes to a distorted conception of where, and from where, the two major lineages of apes originated and dispersed.
This new evidence suggests that there is likely an underappreciated number of significant ape fossils located in Northern Africa and the Middle East. It also provides additional direction for future field research to be conducted in currently poorly sampled areas.
Filling in these gaps in geographic understanding, and in the evolutionary history of humans and apes, will not result in an immediate overhaul of current ideas.
However, it will help fill in missing links between geological and evolutionary events across multiple regions.
Research findings are available online in the journal Science.
The original story “Scientists are rethinking the origins of living apes” is published in The Brighter Side of News.
Like these kind of feel good stories? Get The Brighter Side of News’ newsletter.
The post Scientists are rethinking the origins of living apes appeared first on The Brighter Side of News.
Leave a comment
You must be logged in to post a comment.