“…Cacti are an important resource, the fruits are consumed fresh or dried, and the stems are a common food for humans or used as fodder for animals (Casas & Barbera, 2002). Although Mexican Cactaceae have a relevant economic and ornamental value, and several studies have analyzed their geographical distribution patterns and endemicity (Godínez-Alvarez & Ortega-Báes, 2007;Gómez-Hinostrosa & Hernández, 2000;Hernández & Bárcenas, 1995, 1996Hernández et al, 2007Hernández et al, , 2010, the knowledge of the environmental factors constraining their distribution and characterizing their fundamental niche is still rather limited, being available only few studies (Carrillo-Ángeles et al, 2016;Godínez-Alvarez & Ortega-Báes, 2007;Ibarra-Díaz Velarde et al, 2016). Cactus richness and endemism in each Mexican state are significantly related to the degree of aridity (Godínez-Alvarez & Ortega-Baes, 2007), a long-term climatic phenomenon, which depends on precipitation, potential evapotranspiration rate, temperature and precipitation seasonality (Maliva & Missimer, 2012), which are the main climatic factors de las especies de Thelocactus y para indagar si comparten el mismo nicho ecológico.…”