The Mexican burrowing toad (Rhinophrynus dorsalis) is the single living representative of the family Rhinophrynidae. It is a unique species in its taxonomy and morphology, with special adaptations to assist them in digging burrows where they spend most of their time. These adaptations include a small pointed snout and face, keratinized structures and a lack of webbing on front limbs, and specialized tongue morphology to assist in feeding on ants and termites underground. The body is nearly equal in width and length. It is a dark brown to black color with a red-orange stripe on its back along with splotches of color on its body. The generic name Rhinophrynus means 'nose-toad', from rhino- (), the combining form of the Ancient Greek (, 'nose') and (, 'toad'). The Mexican burrowing toad has had no living relatives for over 190 million years, making its evolution completely independent of other amphibians. It is less genetically similar to any other amphibian compared to how genetically similar mammals such as the fruit bat, polar bear, killer whale, and human are to each other. Its closest sister group is Pipidae, or the aquatic clawed frogs. Description The Mexican burrowing toad has a unique appearance that makes it easy to distinguish from other organisms. This species’ body is flat with a width and length that are almost equal. It is covered in loosely fitting wrinkled skin which becomes taut and shiny when the frog’s body swells up during its mating call. Its head is small and triangular, and projects out of its body in a small point with very small eyes. They have no neck and no visible ear holes or tympanum. Its legs are short and muscular, and are structured for burrowing as indicated by its name. Its feet also have adaptations for burrowing, mainly nail-like keratinized structures at the end of each digit. Its front feet lack webbing between the digits to free them up for burrowing, and its back feet are short and extensively webbed.. The toad’s coloration ranges from a dark brown to black. A bright red-orange stripe runs on its back from head to tail, and the body is covered with other red-orange splotches in varying patterns. Its underside is gray to dark brown and does not have the red splotches like the rest of the body. The toad is sexually dimorphic, with females being larger than males. Adults of the Mexican