Leiopelmatidae

Leiopelmatidae, or New Zealand and North American primitive frogs, is a family belonging to the suborder Archaeobatrachia. There are only four Leiopelma and two Ascaphus species alive now. Leiopelma are only found in New Zealand. Ascaphus are only found in North America.
Overview.
Leiopelmatidae have an extra vertebrae. They have the remains of the tail muscles.
When Leiopelmatid jump, they land in a "belly flop". After landing, Ascaphus skids to a halt before recovering.
They are very small frogs, only in length. Most species lay their eggs in moist ground, typically under rocks or plants. After hatching the tadpoles nest in the male's back. They do not need standing or flowing water. Life span may be long at more than 30 years.
Species.
Family LEIOPELMATIDAE
Extinct species.
Three extinct species are known by subfossil remains, also from New Zealand. They became extinct during the past 1,000 years.
Much older fossils, dating back to the Jurassic, have been found in Argentina, such as "Notobatrachus".