Mystery Bone Discovered in Heart of Chimpanzees Has Never Before Been Seen in Primates

Scientists have discovered that some chimpanzees have a "rare" bone in their heart, which has never been detected before in primates.

Known as the "os cordis," researchers have only identified the bone, which is located within the heart tissue, in a handful of animals and its function is still unclear.

"It is believed that [the bone] helps supporting the structure of the heart and it may also play a role in electrical signalling," Catrin Rutland, lead author of a study detailing the findings from the University of Nottingham in the U.K., told Newsweek.

"It is considered a normal finding in some species, such as cattle, while in other species such as dogs it may be related to cardiac disease," Rutland said. "It is found in large ruminants, otters, camels, and some reptiles."

Rutland and her colleagues discovered the bone while conducting a detailed study of chimpanzee hearts in order to detect anatomical features or signs of disease. Cardiovascular disease is common in zoo-housed chimps—a species that is endangered in the wild.

Thus, understanding more about chimp hearts could have important implications for the conservation of these animals, as well as managing their health.

The scientists detected the bone after conducting scans of chimp hearts using micro-computed tomography—an advanced 3-D X-ray imaging technique that has a much higher resolution than standard hospital or veterinary CT scans, according to a study published in the journal Scientific Reports.

"This is the first time chimp hearts have been scanned using this advanced technology. It was amazing to see the tiny bones within the heart," Rutland told Newsweek. "In our chimpanzees, the os cordis was small, up to 7.6 millimeters wide, but in other animals such as cattle they can be many centimeters long. The chimpanzee heart bone itself is hollow with fine structures of bone within it, which we call trabecular bone."

os cordis bone
A scan of the os cordis bone. Catrin Rutland

Rutland said the discovery is significant because it is the first time that an os cordis has been detected in primates.

"The discovery of a new bone in a new species is a rare event, especially in chimps which have such similar anatomy to people," she said in a statement.

Intriguingly, all of the chimps that had an os cordis in the study were also affected by a condition known as idiopathic myocardial fibrosis—scarring of the heart muscle of unknown origin—that is the most common type of heart disease in the animals.

"[This] may indicate that the presence of os cordis may be a pathological finding in this species—linked to heart disease," Rutland told Newsweek.

"Chimpanzees are endangered in the wild, thus the study of causes and mechanisms of cardiac disease is paramount in order to protect this species and maintain healthy captive populations. The possibility of os cordis occurring in humans suffering from similar cardiovascular disorders should be considered. People also suffer from fibrosis and may also have an os cordis."