The discovery of the 20,000-year-old remains of a giant panda in a cave in southern China is making us rethink much of the things we knew about these gentle and lazy creatures.
It turns out that their distant past was much more interesting than previously imagined, and giant pandas had a whole secret distinct lineage we never even knew about.
Today’s giant pandas (Ailuropoda melanoleuca) live only within a restricted territory in central China, limited to just three provinces: Shaanxi, Gansu, and Sichuan.
But the finding of giant panda remains in the southeastern province of Guangxi reveals these majestic creatures were once a lot more widespread than they are today.
In fact, according to National Geographic, previous discoveries of fossil fragments showed that ancient giant pandas once lived all across China, Myanmar, and northern Vietnam, reaching as far away as Hungary and even Spain.
When You Set Off To Find A Giant Ape But You Come Home With A Giant Panda Instead
What’s so unusual about the 22,000-year-old fossil uncovered in Guangxi, aside from its notable age, is that it was found in a cave — the very last place you’d go looking for a giant panda today.
The researchers themselves, led by paleoanthropologist Yingqi Zhang from the Chinese Academy of Sciences, weren’t searching for panda bones when they stepped inside the Cizhutuo Cave in Guangxi. The team went there in August 2014 to look for evidence of Gigantopithecus — the real-life King Kong, or the largest known primate to ever live, the Inquisitr reported a while back.
Emerging from the Chinese cave with a mélange of old bones, the team uncovered among the fossils an ancient lower jaw belonging to a long-lost group of giant pandas.
While the researchers haven’t officially identified and named a new species, they can tell us for sure that the 20,000-year-old fossil belongs to an extinct lineage of giant pandas that has now been included in the giant panda family tree.
In a new study published yesterday in the journal Current Biology, the newfound fossil, which has become known as the Cizhutuo panda, is hailed as a “unique specimen” that could tell us more about ancient giant pandas of the Last Glacial Maximum — the final portion of the last glacial period when most of North America, Europe, and Asia was covered in ice sheets, explains ZME Science.
“Its date and location in Guangxi, where no wild giant pandas live today, as well as the difficulty of DNA preservation in a hot and humid region, place it as a unique specimen to learn about ancient giant pandas from the Last Glacial Maximum.”
Long-Lost Lineage Of Giant Pandas
While the diversity of pandas has been proven before, the new study comes with significant discoveries in terms of working with degraded fossils to extract their DNA, notes National Geographic.
The research boasts the first-ever complete sequence of mitochondrial DNA (mtDNA) belonging to an ancient panda — which is also the oldest known panda DNA sample ever obtained.
Science Daily reports on the process of sequencing the mitochondrial genome of the ancient giant panda, which was not easy to pull off considering that the fossil was found in a subtropical environment where DNA preservation and recovery is tricky to achieve.
“We not only opened the possibility to get ancient DNA from a quite hot place, but also [from bones that are] quite old,” says study co-author Qiaomei Fu, a geneticist at the Chinese Academy of Sciences and the leader of the fossil’s genetic analysis.
The team ended up sequencing nearly 150,000 fragments of giant panda mtDNA, which they compared with similar samples from 138 present-day bears and 32 ancient bears in order to construct the giant panda family tree.
The genetic analysis revealed that the Cizhutuo panda and modern-day pandas had a common ancestor that lived some 183,000 years ago.
“Using a single complete mtDNA sequence, we find a distinct mitochondrial lineage, suggesting that the Cizhutuo panda, while genetically more closely related to present-day pandas than other bears, has a deep, separate history from the common ancestor of present-day pandas,” Fu pointed out.
Adapted For Subtropical Life
The researchers believe that the two lineages split sometime between 144,000 to 227,000 years ago, with the Cizhutuo panda evolving into a completely new group of pandas that is now extinct.
These long-lost cousins of today’s giant pandas may have been specifically adapted to survive in the subtropical environment of the region where the 22,000-year-old fossil was found.
This speculation comes from the discovery of 18 genetic mutations in the fossil’s mitochondrial genome, which possibly altered the structure of proteins across six mitochondrial genes — something that has been tied to either the specific living conditions of the Guangxi habitat or the climatic differences occurring during the Last Glacial Maximum.
Particularly striking is the new group’s maternal lineage, which “had a long and unique history that differed from the maternal lineages leading to present-day panda populations,” notes Science Daily, citing Cell Press.
Fu believes that much more could be uncovered by sequencing the more extensive nuclear genome of the ancient giant panda.
“Comparing the Cizhutuo panda’s nuclear DNA to present-day genome-wide data would allow a more thorough analysis of the evolutionary history of the Cizhutuo specimen, as well as its shared history with present-day pandas.”