Published in Herp Review: https://ssarherps.org/herpetological-review-pdfs/
"Here we discuss the northernmost records of B. sigma in Sonora, Mexico. Records are from the Madrean Discovery Expeditions (MDE) program of GreaterGood.org in Tucson, Arizona, fieldwork by the authors, and specimens in the University of Arizona Herpetological Collection (UAZ) and the University of Texas at El Paso Biodiversity Collections (UTEPBC). Observations and images are available in the MDE database (madreandiscovery.org) and the Arizona State University Herpetological Collection photo vouchers (ASU HP)."
