A previously unidentified set of salivary glands located in the human head may play a role in swallowing, say researchers who stumbled across them while looking at cranial scans of prostate cancer patients.
From Science Alert:
"To our knowledge, this structure did not fit prior anatomical descriptions," the researchers explain in their paper.
"It was hypothesised that it could contain a large number of seromucous acini, with a physiological role for nasopharynx/oropharynx lubrication and swallowing."
As for how the glands haven't previously been identified, the researchers suggest the structures are found at a poorly accessible anatomical location under the skull base, making them hard to make out endoscopically. It's possible duct openings could have been noticed, they say, but might not have been noticed for what they are, being part of a larger gland system.