Leiopelmatidae (see family information on Tree of Life site)
One of the more primitive of the living frog families, it shares many features generally thought to be inherited from the common ancestor of Leiopelmatidae and the Tailed Frogs (Family Ascaphidae) of western North America. These are medium-sized frogs with vertical pupils, broad heads, and smooth skin on the soles of their feet. The family includes four living species in the genus Leiopelma, which is endemic to New Zealand. However, these currently are found only in relictual populations on coastal islands. Some fossils are known, as early as the Early Miocene (16-19 ma), but many are from the Holocene (roughly 10,000 years ago to the present) on the mainland; these probably went extinct about 1000 years ago. One of the largest fossil species is Leiopelma waitomoensis†, which reached 100 mm SVL compared to extant species, which reach a maximum of 50 mm SVL.
Adults guard their clutches of direct-developing eggs. Young of L. hamiltoni and L. archeyi climb onto the backs of parents to complete their development. Leiopelmatids are nocturnal and catch their prey by lunging at it, as they do not have protrusible tongues (unlike most frogs). They also use alternating kicks when swimming (unlike most frogs). This family does not vocalize, but frogs are known to squeak when molested. These frogs possess: 1) inscriptional ribs (cartilage embedded within abdominal muscle); 2) nine presacral vertebrae (as in Ascaphidae); 3) retention of caudalipuboischiotibialis ("tail-wagging") muscles (as in Ascaphidae). Ascaphus and Leiopelma share many primitive characters, and there are apparently no derived characters that unite them as closest relatives. However, DNA sequences consistently place Ascaphidae and Leiopelmatidae as closest relatives.
Photo by David Green
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Genus Leiopelma (4 species)
Citation: AmphibiaWeb: Information on amphibian biology
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