While technically in Sonora, I collected this no more than 20 yards into Mexico and know from museum specimens that this occurs throughout the Southwest. This was taken on a private ranch that borders the San Bernardino NWR in SE AZ. Like most Tenebs in the southwest, Gonasida is a nocturnal scavenger. Specimens were always found on, or en route to Pogonomyrmax trash piles at dusk. When disturbed, some had the tendency to regurgitate a liquid from their mouths. The upturned pronotal flanges and the long legs and body form serve to characterized this genera.