It wasn’t only our ancestors that had to deal with tuberculosis. Evidence suggests that the ancient relatives of plesiosaurs also suffered from the disease, as detailed in a new study published in Royal Society Open Science.
Researchers have described a series of lumps and bumps found on the ribs of a large marine reptile that was last swimming the oceans during the Middle Triassic, before dinosaurs had even evolved. The team concluded that the lesions may well be the result of the earliest known case of pneumonia. Not only that but in humans these blebs have only been seen in those with tuberculosis (TB), suggesting that this ancient reptile may have been suffering from TB.
The evidence was found on at least four of the ribs of the marine animal that lived some 245 million years ago. Needless to say, this is by far the oldest evidence of either pneumonia or TB unearthed so far.
While the two diseases are indeed different, infections by the bacteria that cause TB have been known to lead to pneumonia. The researchers are unable to ascertain exactly which may have caused the lesions, although a particular pathology seen in some of the vertebrae show a resemblance to that caused by Pott’s disease, in which TB invades the bones in the spine.
The remains of the animal are difficult to conclusively identify – due mainly to the fact that the fossil record from this time is so fragmentary – however, the researchers have so far narrowed it down to an eosauropterygian. These were the early ancestors to the more well-known plesiosaurs and are thought to have had a similar appearance and lifestyle to these long-necked marine reptiles.
Obviously, there is no way to verify what caused these blebs for certain, but an analysis of the lesions has ruled out fractures, cancer, and even scurvy, according to the authors of the paper. The fact that the pathology has altered the bones suggests that it was a pulmonary infection lasting for a significant period of time.
Conditions like this are not unheard of in other animals. Badgers famously act as reservoirs of TB, and even reptiles are known to get similar infections in their lungs. But what is intriguing is the fact that seals are the marine mammal group most susceptible to TB. This is interesting, because some of the descendants of the Middle Triassic animal, such as Nothosaurus, have been previously hypothesized to lead lives similar to that of seals, diving deep to catch food and hauling themselves up on rocks. This raises the possibility that this lifestyle may make animals particularly susceptible to the disease.