Leiopelmatidae, or New Zealand and North American primitive frogs, is a family belonging to the suborder Archaeobatrachia. Their relatively primitive form indicates that they have an ancient lineage.2] The North American frogs of the Genus Ascaphus are now united with the New Zealand frogs of the genus Leiopelma in the Leiopelmatidae family Only four Leiopelma and two Ascaphus extant species are known to belong to the family. Leiopelma are only found in New Zealand. Ascaphus are only found in North America.
Their defining characteristics are their extra vertebrae (bringing the total to nine) and the remains of the tail muscles (the tail itself is absent in adults, although it is present in the younger frogs, who need the extra skin surface until their lungs are fully developed). The family Ascaphidae (found only in North America), of the same suborder, share these "unique" characteristics, and hence the two have often been described as related, or even part of the same family.
Late jump recovery is unique in Leiopelmatidae. When Leiopelmatid spp. jump, they land in a "belly flop" fashion repositioning their limbs for takeoff for the next jump only after hitting the ground with the ventral surface of the torso. After landing, Ascaphus skids to a halt before recovering. The appearance of early jump recovery in more advanced taxa is a key innovation in anuran evolutio n.
They are unusually small frogs, only 5 centimetres (2.0 in) in length. Most species lay their eggs in moist ground, typically under rocks or vegetation. After hatching the tadpoles nest in the male's back, all without the need for standing or flowing water. However, Hochstetter's frog lays its eggs in shallow ponds and has free-living tadpoles, although they do not swim far from the place of hatching, or even feed, before metamorphosing into adult frogs. Life span may be long (more than 30 years) for such small organisms.
- Genus Leiopelma
- Archey's Frog, Leiopelma archeyi Turbott, 1942
- Hamilton's Frog, Leiopel ma hamiltoni McCulloch, 1919
- Hochstetter's Frog, Leiopelma hochstetteri Fitzinger, 1861
- Maud Island Frog, Leiopelma pakeka Bell, Daugherty & Hay, 1998
- Genus Ascaphus
- Tailed Frog, Ascaphus truei
- Rocky Mountain Tailed Frog, Ascaphus montanus
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, and also considered to belong to this family, have been found in Argentina, such as Notobatrachus.
- Frogs of New Zealand