* Above, a missing link? The pyramid at Huapalcalco.
A possibly "new" Mesoamerican culture has been discovered in the state of Hidalgo. Investigators at the National Institute of Anthropology and History (INAH) in Hidalgo told the daily Excelsior that 41 artifacts found near the community of Huajomulco in the Valley of Tulancingo carry traits similar to the dominant cultures of the region but are distinctly different. The sculptures and figures are said to date from between 600-700 and 900 A.D., Mesoamerica's epiclassic period, said INAH archeologist Carlos Hernández Reyes. These artifacts may provide a crucial link to the obscure Huapalcalco pyramid, a subject of debate among archeologists:
In this period, he said, the region saw the development of the Coyotlatelcol culture, which appeared in Tula. But not in Tulancingo. The Huajomulco culture could be placed within this interval.
[...]
"We've worked at the pyramid and I can assure you it is not teotihuacana; neither the technique of the contruction nor the proportions are. As for the ceramic work, it is also not teotihuacana, but rather refers to the Huajomulco culture."
There is some contention however over the authencity of the discovered artifacts, Excelsior says. The pieces are now on display at the Museo de Datos Historicos de Tulancingo. * Here is the only serviceable image I found of the objects, at the local paper, El Sol de Tulancingo.