The Xi'iuy or Pame are an Oto-Pamean (Oto-Manguean), NOT Uto-Aztecan, Indigenous people of the Sierra Gorda -- linguistically and culturally distinct from their Uto-Aztecan-speaking Chichimeca neighbors (Guachichil, Zacateco, Guamare). Described by Spanish chroniclers as the most pacific of the Chichimeca nations at the start of the Chichimeca War, they are -- along with the Chichimeca Jonaz -- one of only two Chichimeca-era peoples to survive colonization as an intact, distinct culture; roughly 10,000-20,000 Pame/Xi'iuy live today in San Luis Potosí and Querétaro, recognized as a living Indigenous people by Mexico's INPI.
NON-TERMINAL: the Pame/Xi'iuy continue to exist today as a distinct, government-recognized Indigenous people of Mexico. Per Mexico's INPI (Instituto Nacional de los Pueblos Indígenas) official Atlas de los Pueblos Indígenas and Catálogo Nacional de Pueblos y Comunidades Indígenas, the Xi'iuy/Pame people live in five municipios of San Luis Potosí (Ciudad del Maíz, Alaquines, Tamasopo, Rayón, Santa Catarina) and three microregions of Jalpan de Serra and Arroyo Seco municipios in Querétaro. English Wikipedia's 'Pame people' article states: 'The Pames, along with the Chichimeca-Jonaz of the Sierra Gorda in eastern Guanajuato, are the only two intact cultural groups of all the peoples known collectively as Chichimecas who have survived colonization.' The map should hand off to modern Mexico (San Luis Potosí and Querétaro states) rather than showing an 'end' for this record.
A Pame/Jonaz-specific scholarly monograph on over 200 years of missionization in the Sierra Gorda, covering exactly this polity's home region. Verified as a real book via Open Library.
An ethnographic monograph specifically on the Xi'oi/Pame people of the Sierra Gorda.
The foundational classic ethnolinguistic study establishing the Otomi-Pame (Oto-Pamean) linguistic grouping and its relationship to the wider Oto-Manguean family -- the primary academic basis for the linguistic-antiquity argument that distinguishes Pame from the Uto-Aztecan Chichimeca nations.