Texas wolf

The Texas wolf ("Canis lupus monstrabilis") is an extinct subspecies of gray wolf, distinct from the Texas red wolf ("Canis lupus rufus"), whose range once included southern and western Texas and northeastern Mexico. 
Description.
It was darker than its more northern cousins, and has a highly arched frontal bone. 
Taxonomy.
It is recognized as a subspecies of "Canis lupus" in the taxonomic authority "Mammal Species of the World (2005)".