Archey’s frog is the world’s most Evolutionarily Distinct and Globally Endangered amphibian species.
Archey’s frog is described as a ‘living fossil’, as it is almost indistinguishable from the fossilised remains of frogs that lived 150 million years ago. This species is the smallest of the prehistoric New Zealand frogs; a group of species that diverged from their nearest relatives over 200 million years ago.
Archey’s frog has bizarre features such as muscles for tail-wagging, despite not having a tail to wag, and also an abnormally high number of vertebrae. They cannot croak and do not possess ear drums, therefore they communicate by scent instead of sound. The males guard the eggs, and the tailed froglets that hatch crawl onto the father’s back, where they remain for several weeks whilst they develop.
The species is able to withstand substantial desiccation, with studies showing that frogs dehydrated to 92% of their body weight could rehydrate to 99% of their body weight in only four hours when placed on wet foliage. Females have been found to have 22 pairs of chromosomes plus a unique W sex determining chromosome, which males do not have. This is unlike us, where both females and males have sex determining chromosomes. Moreover, these populations tend to have many superfluous chromosomes, which are considered as ‘genetic junk’ as they appear to serve no purpose.
Disease has led to the decline of this species, in particular the infamous chytrid fungus, but the species is also threatened by introduced predators such as mice and rats. Consequently, Archey’s frog is listed as Critically Endangered by the IUCN Red List. The Auckland Zoo has established a new facility for breeding and maintaining the species.
- Order: Anura
- Family: Leiopelmatidae
- Population: Once abundant
- Trend: decreasing
- Size: <38mm
This species occurs in the Whareorino range in the west and Coromandel ranges in the east on North Island, New Zealand. Ranges from 400-1,000m above sea level
Habitat and Ecology
This is a terrestrial and nocturnal species, living mostly at higher altitudes in forested ranges and more open sub-alpine scrub. Mating takes place in shallow depressions beneath logs or stones, where it cool and moist. The female lays unpigmented eggs in damp areas on the ground where direct development of young occurs within the egg as the young hatch as miniature adults. They feed on small insects, worms and other invertebrates. They avoid predation by having poison glands around their heads but they also use camouflage which combined with their lack of vocalisations, makes them difficult to locate.