Crotalus willardi meridionalis, the southern ridge-nosed rattlesnake, is a subspecies of ridge-nosed rattlesnake native to Durango and Zacatecas, Mexico. As with all rattlesnakes, it is venomous.
Crotalus willardi meridionalis differs from its sister subspecies by lacking a stripe along its rostral and mental along with other headmarkings and by its specific scale count. Its rattle is sheathed by sharp scales, as is characteristic of the species.
Crotalus willardi meridionalis is known to be ovoviviparous.
The name 'meridionalis' the latitude it was found in.