Leiopelma hamiltoni

Hamilton's frog | Pepeketua

Leiopelma hamiltoni
(McCulloch, 1919)

Hamilton's frog (Te Pākeka / Maud Island). © Nick Harker
Image attribution
Hamilton's frog (Te Pākeka / Maud Island). © Nick Harker
Herpetofaunal category
NZ Frogs
Species complex
Conservation Status
Threatened - Nationally Vulnerable
Common names
Hamilton's frog,
Maud Island frog.

Length: SVL: Males up to 43mm; Females up to 52mm

Weight: unknown

Description

New Zealand’s rarest and largest native frog, with females reaching SVLs (snout-vent-lengths) of up to 52mm, and males reaching SVLs of 43mm. Hamilton's frogs were formerly widespread but by the time of their discovery were restricted to just two small populations in the Marlborough Sounds.

Dorsal (upper) surfaces are light to dark brown, often with a pattern of black blotches which are most-pronounced along the dorso-lateral margin, and vary in number and intensity between individuals. Ventral (lower) surfaces are light brown. Hind feet have almost no webbing, which is an adaptation to living on rocky ground.

Similar in appearance to the related Archey's frog (Leiopelma archeyi) which occurs on the Coromandel Peninsula and in Whareorino forest. However, Hamilton's frogs are often more drab and less-variable in colouration, as well as being more robust in build and much larger than Archey's frogs. 

Life expectancy

Unknown exactly how long their natural lifespan might be. However, there are wild individuals which have been monitored over 40 years.

Distribution

According to sub-fossil evidence, Hamilton’s frog were once widespread from Waikato to Punakaiki. However at the time of their discovery they had only survived on Takapourewa / Stephen's Island and Te Pākeka / Maud Island, in the Marlborough Sounds.

They have since been translocated from both Maud Island and Stephen's Island to several other islands in the Marlborough Sounds (including Long Island, Motuara Island and Nukuwaiata), and to Zealandia - a mainland sanctuary in Wellington.

Distribution maps are simplified, predicted distributions based on a combination of known distribution data, historical distribution data, suitability of habitat, and known biogeographic patterns. In some cases, the potential distribution of a species may be very unlikely. However, due to the cryptic nature of some of New Zealand's herpetofauna, it should not be ruled out entirely. Only significant historical records outside the known range of each species are used. 

Ecology and habitat

A nocturnal and terrestrial species. Hamilton's frogs emerge on humid nights (particularly during light rain) to hunt for insects.

Hamilton’s frog inhabit deep rock piles in native forest or live under logs and rocks on the forest floors. The species have a small home range (<5m) and are known to climb several meters in trees and ferns.

Social structure

Largely unknown. However, they occur at high-density in appropriate habitat (~1000 frogs per hectare).

Breeding biology

Females lay 1-19 eggs in damp recesses on the ground, in trees, or in the crown of tree ferns. The male guards the eggs for 14-21 weeks until they hatch. Tadpoles have no aquatic stage, they remain within the egg and hatch out as fully-formed froglets, which are carried around on the males back for several weeks.

Diet

Hamilton's frogs consume a wide range of small invertebrates.

Disease

Hamilton’s frog are at risk of diseases such as amphibian chytrid fungus.

Conservation

Hamilton’s frog are listed as ‘vulnerable’ on the IUCN red list. In the 2013 threat classification series DOC listed the Te Pākeka / Maud Island and Takapourewa / Stephen's Island populations separately with Leiopelma hamiltoni (Stephen's Island) categorised as ‘nationally critical’ and Leiopelma pakeka (Maud Island) as ‘nationally vulnerable’ (both groups are now considered to be one species).

Threats to Hamilton’s frog include introduced predators, disease, habitat change and destruction. Intra and inter island translocations took place in 1992, 2004 and 2006. On Stephens Island tuatara were preceived to be a threat to Hamilton’s frog due to their abundance and the small area the frogs were occupying. In 2006 a group of 21 frogs were translocated from Maud Island to Zealandia Sanctuary.

Interesting notes

The common, and specific name 'hamiltoni' references Harold Hamilton (1885-1937), a biologist who discovered the species on Takapourewa/Stephen's Island (van Winkel et al., 2018).

The Te Pākeka / Maud Island population were named as a separate species (Leiopelma pakeka) in 1998 as a result of allozyme DNA studies, which suggested they were a distinct species. Further genetic studies ensued, it was later postulated that the allozyme data reflected a genetic bottleneck (resulting from the isolation and small size of the populations), and the two groups are now considered to be a single species.

The Hamilton's frog belongs to a clade (group) which includes its sister species Archey's frog (Leiopelma archeyi), and the extinct Waitomo frog (Leiopelma waitomoensis) (Worthy, 1987).

The skeletal morphology of Archey's and Hamilton's frogs are so similar that it is hard to determine their exact historical distribution based on fossil remains (Worthy, 1987). 

References

Altobelli, J. T., Lamar, S. K., & Bishop, P. J. (2021). Archaic, terrestrial Hamilton’s frogs (Leiopelma hamiltoni) display arboreal behaviours. New Zealand Journal of Ecology45(2), 1-6.

Bell, B. D. (1978). Observations on the ecology and reproduction of the New Zealand Leiopelmid frogs. Herpetologica, 340-354.

Bell, B. D. (1994). A review of the status of New Zealand Leiopelma species (Anura: Leiopelmatidae), including a summary of demographic studies in Coromandel and on Maud Island. New Zealand journal of zoology21(4), 341-349.

Bell, B. D. (2010). The threatened Leiopelmatid frogs of New Zealand: Natural history integrates with conservation. Herpetological Conservation and Biology5(3), 515-528.

Bell, B. D. (2011). Long term population monitoring of the Maud Island frog and Archey’s frog, Victoria University of Wellington. FrogLog, 99, 40-41.

Bell, B. D., Daugherty, C. H., & Hay, J. M. (1998). Leiopelma pakeka, n. sp.(Anura: Leiopelmatidae), a cryptic species of frog from Maud Island, New Zealand, and a reassessment of the conservation status of L. hamiltoni from Stephens Island. Journal of the Royal Society of New Zealand28(1), 39-54.

Bell, B. D., Easton, L. J., Walker, K. J., & Woolley, C. K. (2019). Physical contact between a native frog (Leiopelma pakeka) and a carnivorous land snail (Powelliphanta hochstetteri obscura): what was going on?. New Zealand journal of zoology46(2), 182-187.

Bell, B. D., & Pledger, S. A. (2010). How has the remnant population of the threatened frog Leiopelma pakeka (Anura: Leiopelmatidae) fared on Maud Island, New Zealand, over the past 25 years?. Austral Ecology35(3), 241-256.

Bell, B. D., Pledger, S., & Dewhurst, P. L. (2004). The fate of a population of the endemic frog Leiopelma pakeka (Anura: Leiopelmatidae) translocated to restored habitat on Maud Island, New Zealand. New Zealand Journal of Zoology31(2), 123-131.

Bell, B. D., & Wassersug, R. J. (2003). Anatomical features of Leiopelma embryos and larvae: implications for anuran evolution. Journal of Morphology256(2), 160-170.

Bell, E. A., & Bell, B. D. (1994). Local distribution, habitat, and numbers of the endemic terrestrial frog Leiopelma hamiltoni on Maud Island, New Zealand. New Zealand journal of zoology21(4), 437-442.

Benno Meyer-Rochow, V., & Pehlemann, F. W. (1990). Retinal organisation in the native New Zealand frogs Leiopelma archeyi, L. hamiltoni, and L. hochstetteri (Amphibia: Anura; Leiopelmatidae). Journal of the Royal Society of New Zealand20(4), 349-366.

Bishop, P. J., Daglish, L. A., Haigh, A., Marshall, L. J., Tocher, M., & McKenzie, K. L. (2013). Native frog (Leiopelma spp.) recovery plan, 2013-2018Threatened species recovery plan 63. Department of Conservation, Wellington, New Zealand.

Brown, D. (1994). Transfer of Hamilton's frog, Leiopelma hamiltoni, to a newly created habitat on Stephens Island, New Zealand. New Zealand journal of zoology21(4), 425-430.

Cash, B., & Gaze, P. (2008). A history of wildlife translocations in the Marlborough Sounds. DOC: Wellington.

Clay, C., Gleeson, D., Howitt, R., Lawrence, H., Abdelkrim, J., & Gemmell, N. (2010). Characterisation of microsatellite markers for the primitive New Zealand frog, Leiopelma hochstetteri. Conservation Genetics Resources2, 301-303.

Daugherty, C. H., Bell, B. D., Adams, M., & Maxson, L. R. (1981). An electrophoretic study of genetic variation in the New Zealand frog genus Leiopelma. New Zealand journal of zoology8(4), 543-550.

Daugherty, C. H., Maxson, L. R., & Bell, B. D. (1982). Phylogenetic relationships within the New Zealand frog genus Leiopelma—immunological evidence. New Zealand journal of zoology9(2), 239-242.

Easton, L. (2018). Taxonomy and genetic management of New Zealand's Leiopelma frogs (Doctoral dissertation, University of Otago).

Easton, L. J., Rawlence, N. J., Worthy, T. H., Tennyson, A. J., Scofield, R. P., Easton, C. J., Bell, B. D., Whigham, P. A., Dickinson, K. J. M., & Bishop, P. J. (2018). Testing species limits of New Zealand’s leiopelmatid frogs through morphometric analyses. Zoological Journal of the Linnean Society183(2), 431-444.

Egeter, B., Robertson, B. C., & Bishop, P. J. (2015). A synthesis of direct evidence of predation on amphibians in New Zealand, in the context of global invasion biology. Herpetological Review46(4), 512-519.

Germano, J. M., Cree, A., & Bishop, P. J. (2011). Ruling out the boys from the girls: can subtle morphological differences identify sex of the apparently monomorphic frog, Leiopelma pakeka?. New Zealand Journal of Zoology38(2), 161-171.

Germano, J. M., Molinia, F. C., Bishop, P. J., Bell, B. D., & Cree, A. (2012). Urinary hormone metabolites identify sex and imply unexpected winter breeding in an endangered, subterranean-nesting frog. General and Comparative Endocrinology175(3), 464-472.

Gleeson, D., & Molinia, F. (2011). Landcare Research (Auckland). FrogLog99, 35.

Green, D. M. (1988). Antipredator behaviour and skin glands in the New Zealand native frogs, genus Leiopelma. New Zealand journal of zoology15(1), 39-45.

Green, D. M. (1988). Heteromorphic sex chromosomes in the rare and primitive frog Leiopelma hamiltoni from New Zealand. Journal of heredity79(3), 165-169.

Green, D. M., Sharbel, T. F., Hitchmough, R. A., & Daugherty, C. H. (1989). Genetic variation in the genus Leiopelma and relationships to other primitive frogs. Journal of Zoological Systematics and Evolutionary Research27(1), 65-79.

Holyoake, A., Waldman, B., & Gemmell, N. J. (2001). Determining the species status of one of the world's rarest frogs: a conservation dilemma. Animal Conservation4(1), 29-35.

Jewell, T. (2011). A photographic guide to reptiles and amphibians of New Zealand. Auckland: New Holland Publishing Ltd.

Karst, T. M. (2013). Mortality mitigation of a translocated rare New Zealand frog Leiopelma pakeka: A thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology.

Lamb, S. D., Altobelli, J. T., Easton, L. J., Godfrey, S. S., & Bishop, P. J. (2022). Captive Hamilton’s frog (Leiopelma hamiltoni) associates non-randomly under retreat sites: Preliminary insights into their social networks. New Zealand Journal of Zoology49(3), 236-251.

Lee, J. S., & Waldman, B. (2002). Communication by fecal chemosignals in an archaic frog, Leiopelma hamiltoni. Copeia2002(3), 679-686.

Lukis, K. (2009). Returning an endemic frog to the New Zealand mainland: Transfer and adaptive management of Leiopelma pakeka at Karori Sanctuary, Wellington: A thesis submitted to Victoria University of Wellington in partial fulfilment of the requirements for the degree of Master of Science (Ecological Restoration)

Melzer, S., & Bishop, P. J. (2010). Skin peptide defences of New Zealand frogs against chytridiomycosis. Animal Conservation13, 44-52.

Melzer, S., & Bishop, P. J. (2011). Just Juice? Attempting to unravel the secrets of skin secretions in New Zealand's endemic frogs. FrogLog99, 37-38.

Melzer, S., Clerens, S., & Bishop, P. J. (2011). Differential polymorphism in cutaneous glands of archaic Leiopelma species. Journal of Morphology272(9), 1116-1130.

Melzer, S., Davis, L. S., & Bishop, P. J. (2012). Cutaneous gland secretions of Leiopelma pakeka as a potential mechanism against rat predation. New Zealand Journal of Zoology39(4), 329-339.

Newman, D. G. (1977). Some evidence of the predation of Hamilton's frog (Leiopelma hamiltoni (McCulloch)) by tuatara (Sphenodon punctatus (Grey)) on Stephens Island. In Proceedings of the New Zealand Ecological Society (Vol. 24, pp. 43-47).

Newman, D. G. (1990). Activity, dispersion, and population densities of Hamilton's frog (Leiopelma hamiltoni) on Maud and Stephens Islands, New Zealand. Herpetologica, 319-330.

Newman, D. G. (1996). Native frog (Leiopelma spp.) Recovery plan: Threatened species recovery plan No. 18. Wellington: Department of Conservation.

Newman, D. G., Bell, B. D., Bishop, P. J., Burns, R., Haigh, A., Hitchmough, R. A., & Tocher, M. (2010). Conservation status of New Zealand frogs, 2009. New Zealand Journal of Zoology37(2), 121-130.

Newman, D.G., Bell, B.D., Bishop, P.J., Burns, R.J., Haigh, A., & Hitchmough, R.A. (2013). Conservation status of New Zealand frogs, 2013: In New Zealand Threat Classification Series 5. DOC: Wellington.

Newman, D. G., Crook, I. G., & Imboden, C. H. (1978). Comparisons of the climates of the two habitats of Hamilton's frog (Leiopelma hamiltoni (McCulloch)). New Zealand journal of ecology, 84-90.

Ohmer, M., & Bishop, P. J. (2011). Susceptibility to chytridiomycosis. FrogLog99, 38-39.

Ohmer, M. E., Herbert, S. M., Speare, R., & Bishop, P. J. (2013). Experimental exposure indicates the amphibian chytrid pathogen poses low risk to N ew Z ealand's threatened endemic frogs. Animal Conservation16(4), 422-429.

Ramírez Saavedra, P. A. (2017). Behavioural patterns of two native Leiopelma frogs and implications for their conservation: a thesis submitted to Victoria University of Wellington in fulfilment of the requirement for the degree of Doctor of Philosophy in Ecology and Biodiversity (Doctoral dissertation, Victoria University).

Ramírez, P. A., Bell, B. D., Germano, J. M., Bishop, P. J., & Nelson, N. J. (2017). Tracking a small cryptic amphibian with fluorescent powders. New Zealand Journal of Ecology41(1), 134-138.

Reilly, S., Essner Jr, R., Wren, S., Easton, L., & Bishop, P. J. (2015). Movement patterns in leiopelmatid frogs: insights into the locomotor repertoire of basal anurans. Behavioural Processes121, 43-53.

Shaw, S. D. (2012). Diseases of New Zealand native frogs (Doctoral dissertation, James Cook University).

Stephenson, E. M. (1955). The head of the frog, Leiopelma hamiltoni McCulloch. Proceedings of the Zoological Society of London, 124(4), 797-801.

Tocher, M. (2011). 'State of the nation' report on New Zealand translocations including a quick overview of past translocations. FrogLog99, 39-40.

Tocher, M. D., Fletcher, D., & Bishop, P. J. (2006). A modelling approach to determine a translocation scenario for the endangered New Zealand frog Leiopelma hamiltoni. The Herpetological Journal16(2), 97-106.

van Winkel, D., Baling, M. & Hitchmough, R. (2018). Reptiles and Amphibians of New Zealand: A field guide. Auckland: Auckland University Press, 376 pp.

Waldman, B., & Bishop, P. J. (2004). Chemical communication in an archaic anuran amphibian. Behavioral Ecology15(1), 88-93.

Webster, J. T. (2004). Individual identification, disease monitoring and home range of Leiopelma hamiltoni: a thesis submitted in partial fulfilment of the requirements for the Degree of Master of Zoology.

Worthy, T. H. (1987). Osteology of Leiopelma (Amphibia: Leiopelmatidae) and descriptions of three new subfossil Leiopelma species. Journal of the Royal Society of New Zealand17(3), 201-251.

Worthy, T. H. (1987). Palaeoecological information concerning members of the frog genus Leiopelma: Leiopelmatidae in New Zealand. Journal of the Royal Society of New Zealand17(4), 409-420.