Evidence of an ancient Mexican ritual of binding a person's skull have been revealed.
Britain's Daily Mail news website says skulls have been found showing a person who suffered cranial disfiguration.
"Believed to be 1000 years old, the find was made near the small Mexican village of Onavas," the Mail said.
"The find is believed to be the first in the region showing the practice of binding a skull to change its shape."
The website quotes archaeologist Cristina Garcia Moreno, director of the research project, as saying the skull deformation was used by Mesoamerican cultures to "differentiate one social group from another and for ritual purposes".
"The burial ground consists of 25 individuals; 13 have intentional cranial deformation and five also have dental mutilation," the Mail reports.
Moreno said: "This unique find shows a mix of traditions from different groups of northern Mexico."
In a video posted to YouTube she said the use of ornaments made from sea shells from the Gulf of California had never been found before in Sonoran territory and this discovery extends the limit of influence of Mesoamerican peoples farther north than has been previously recorded.
"Some of the individuals were wearing ornaments such as as bangles, nose rings, earrings, pendants made from shells found in the Gulf of California, and one burial contained a turtle shell, carefully placed over the abdomen, according to Past Horizons."