Australian green tree frog Dryopsophus caeruleus, copyright ebonyb82.

Belongs within: Hyloidea.

When the going gets tough, the tough get digging
Published 5 April 2023

In most people’s minds, frogs are associated with stagnant ponds, limpid pools and sodden swamps. So you might be forgiven for thinking that the desert lands of Australia would not be welcoming to frog-kind, that the only hopping in the area would be done by kangaroos. Nevertheless, Australia is home to a wide diversity of native frog species, some of which exhibit remarkable adaptations to their harsh environment.

Water-holding frog Cyclorana platycephala, copyright Tnarg 12345.

Cyclorana has commonly been recognized as a genus containing a baker’s dozen of frog species widespread across northern and central Australia. They form part of the Australasian treefrogs or bell frogs of the Pelodryadidae (historically included in the Hylidae; Duellman et al. 2016). Some reach large sizes with the giant frog C. australis and New Holland frog C. novaehollandiae each about ten centimetres in length. Cyclorana species differ from other pelodryadids in adaptations for digging such as the absence of discs or pads on the fingers and toes and the first finger opposed to the remaining digits (Cogger 2018). However, though most authors have agreed that the Cyclorana frogs themselves form a coherent group (with the occasional exception of the striped burrowing frog C. alboguttata), they have sometimes fallen as collateral damage to shifting classifications of related pelodryadids. Duellman et al. (2016) subsumed Cyclorana within a larger genus Dryopsophus. In this post, I’m still using Cyclorana for convenience’s sake.

Main’s frog Cyclorana maini, copyright Alexandre Roux.

Species of Cyclorana are mostly found in savannah woodland and desert (Anstis et al. 2016). They are usually only seen after rainfall, during which time they call and breed in temporarily inundated pools and streams. During the intervening dry periods, they burrow underground and aestivate in buried chambers. Chambers vary from a few centimetres below the surface to at least a foot deep (Tracy et al. 2007), presumably depending on species and/or local soil conditions. The frogs adopt a ‘water-conserving’ posture, crouched with legs drawn tight against the body. Large amounts of water may be held in the bladder. Over time, the frogs become encased within a leathery cocoon that entirely covers the body except for the nostrils. Microscopic examination of the cocoon reveals a layered structure (Withers 1995) indicating its formation from shed layers of epidermis. Interestingly, there are few if any indications of overt changes in the frog’s metabolism during aestivation. Skin is not shed at a different rate from normal (one layer every few days) and cocoon formation seems as much a by-product of the immobile frog not cleaning shed layers away as anything else. The frog remains responsive to disturbance and readily breaks free from the cocoon by simply moving about (though the process does naturally become slower as the cocoon grows thicker). Nevertheless, some species of Cyclorana may remain inert for remarkable periods with up to five years recorded for the water-holding frog C. platycephala. That is indeed a long time between drinks.

Systematics of Pelodryadinae
<==Pelodryadinae [Chiroleptina, Chiroleptinae, Cycloraninae, Nyctimystinae]DMH16
|--Nyctimystes Stejneger 1916 [incl. Sandyrana Wells & Wellington 1985]DMH16
| | i. s.: N. avocalis Zweifel 1958DMH16, FG06 [=Litoria avocalisFG06]
| | N. bivocalisDMH16
| | N. calcaratusDMH16
| | N. daymani Zweifel 1958DMH16, FG06 [=Litoria daymaniFG06]
| | N. disruptus Tyler 1963DMH16, FG06 [=Litoria disruptaFG06]
| | N. eucavatusDMH16
| | N. fluviatilis Zweifel 1958DMH16, FG06 [=Litoria fluviatilisFG06]
| | N. granti (Boulenger 1914)DMH16, FG06 [=Litoria grantiFG06]
| | N. gularis Parker 1936DMH16, FG06 [=Litoria gularisFG06]
| | N. intercastellusDMH16
| | N. kudukiDMH16
| | N. latratusDMH16
| | N. montanus (Peters & Doria 1878)DMH16, FG06 [=Litoria montanaFG06]
| | N. myolaeDMH16
| | N. obsoletus (Lönnberg 1900)DMH16, FG06 [=Litoria obsoletaFG06]
| | N. ocreptusDMH16
| | N. perimetri Zweifel 1958DMH16, FG06 [=Litoria perimetriFG06]
| | N. persimilis Zweifel 1958DMH16, FG06 [=Litoria persimilisFG06]
| | N. purpureolatusDMH16
| | N. rueppelli (Boettger 1895)DMH16, FG06 [=Litoria rueppelliFG06]
| | N. sanguinolentaDMH16
| | N. trachydermis Zweifel 1983DMH16, FG06 [=Litoria trachydermisFG06]
| | N. traunaeDMH16
| | N. tyleri Zweifel 1983DMH16, FG06 (see below for synonymy)
| |--+--N. duxDMH16 [=Litoria duxPW11]
| | `--N. infrafrenatus (Günther 1867)DMH16 (see below for synonymy)
| `--+--N. brevipalmatus (Tyler, Martin & Watson 1972)DMH16, C18 [=Litoria brevipalmataPW11]
| `--+--+--N. kubori Zweifel 1958DMH16, FG06 [=Litoria kuboriPW11]
| | `--N. narinosa Zweifel 1958FG06 [=Litoria narinosusPW11]
| `--+--+--N. cheesmanae Tyler 1964DMH16, FG06 [=Litoria cheesmaniPW11]
| | `--+--*N. papua Boulenger 1897DMH16, FG06 [=Litoria papuaPW11]
| | `--N. pulcher Wandolleck 1911FB17, FG06 [=Litoria pulcherPW11]
| `--+--+--N. foricula Tyler 1963DMH16, FG06 [=Litoria foriculaPW11]
| | `--N. semipalmatus Parker 1936FG06 [=Litoria semipalmatusPW11]
| `--+--N. humeralis Boulenger 1912DMH16, FG06 [=Litoria humeralisPW11]
| `--N. zweifeli Tyler 1967FG06 [=Litoria zweifeliPW11]
`--Dryopsophus Fitzinger 1843 (see below for synonymy)DMH16
| i. s.: D. aruensisDMH16
| D. auaeDMH16
| D. beckiDMH16
| ‘Phractops’ brevipalmatusF13
| D. brongersmaiDMH16
| D. bulmeriDMH16
| D. callistusDMH16
| D. dorsivenusDMH16
| D. elkeaeDMH16
| D. eschatusDMH16
| D. fusculusDMH16
| D. gramineaDMH16
| D. kroombitensisDMH16
| D. loricusDMH16
| D. mackiDMH16
| D. myolusDMH16
| D. napaeusDMH16
| D. piperatusDMH16
| D. prattiDMH16
| D. rarusDMH16
| D. rivicolusDMH16
| D. robinsonaeDMH16
| D. sauroniDMH16
| D. spiniferusDMH16
|--+--+--D. kumaeDMH16 [=Litoria kumaePW11]
| | `--+--D. gracilentus (Peters 1869)DMH16, C18 [=Litoria gracilentaPW11]
| | `--+--D. chloris (Boulenger 1893)DMH16, C18 [=Litoria chlorisPW11]
| | `--D. xanthomerus (Davies, McDonald & Adams 1986)DMH16, C18 [=Litoria xanthomeraPW11]
| `--+--D. splendidus (Tyler, Davies & Martin 1977)DMH16, C18 [=Litoria splendidaPW11]
| `--+--D. gilleni (Spencer 1896)DMH16, C18 [=Litoria gilleniPW11]
| `--+--D. caeruleus (White 1790)DMH16 [=Rana caeruleaDMH16, Litoria caeruleaPW11, *Pelodryas caeruleaDMH16]
| `--D. cavernicolus (Tyler & Davies 1979)DMH16, DAP09 [=Litoria cavernicolaPW11]
`--+--+--+--D. genimaculatusDMH16 [=Litoria genimaculataPW11]
| | `--+--D. eucnemis (Lönnberg 1890)DMH16, C18 [=Litoria eucnemisPW11]
| | `--+--D. exophthalmusDMH16 [=Litoria exophthalmiaPW11]
| | `--D. serratusDMH16
| `--+--D. andiirrmalin (McDonald 1997)DMH16, C18 [=Litoria andiirrmalinPW11]
| `--+--D. lesueurii (Duméril & Bibron 1841)DMH16 (see below for synonymy)
| `--+--D. booroolongensis (Moore 1961)DMH16, C18 [=Litoria booroolongensisPW11]
| `--+--D. jungguy (Donnellan & Mahony 2004)DMH16, C18 [=Litoria jungguyPW11]
| `--D. wilcoxii (Günther 1864)DMH16, C18 [=Litoria wilcoxiiPW11]
`--+--+--D. spenceri (Dubois 1984)DMH16, C18 [=Litoria spenceriPW11]
| `--+--+--D. daviesae (Mahony, Knowles et al. 2001)DMH16, PW11 [=Litoria daviesaePW11]
| | `--D. subglandulosus (Tyler & Anstis 1983)DMH16, C18 [=Litoria subglandulosaPW11]
| `--+--*D. citropus (Péron 1807)DMH16 [=Hyla citropaDMH16, Litoria citropaPW11]
| `--+--+--D. barringtonensisDMH16 [=Litoria barringtonensisPW11]
| | `--D. pearsonianus (Copland 1961)DMH16, C18 [=Litoria pearsonianaPW11]
| `--+--D. nudidigitus (Copland 1962)DMH16, C18 [=Litoria nudidigitaPW11]
| `--D. phyllochrous (Günther 1863)DMH16, C18 [=Litoria phyllochroaPW11]
`--+--+--D. dayiDMH16
| `--+--D. nannotis (Andersson 1916) [=Hyla nannotis, *Mosleyia nannotis]DMH16
| `--+--D. nyakalensisDMH16
| `--D. rheocolusDMH16
`--+--D. impurusDMH16
`--+--+--D. raniformis (Keferstein 1867)DMH16, C18 (see below for synonymy)
| `--+--D. aureus (Lesson 1829)DMH16, C18 (see below for synonymy)
| `--+--D. cyclorhynchus (Boulenger 1882)DMH16, C18 [=Litoria cyclorhynchaPW11]
| `--D. moorei (Copland 1957)DMH16, C18 [=Litoria mooreiPW11]
`--+--D. dahlii (Boulenger 1896)DMH16, C18 [=Cyclorana dahliiBC06, Litoria dahliiPW11]
`--+--+--D. australis (Gray 1842)DMH16 (see below for synonymy)
| `--D. novaehollandiae (Steindachner 1867)DMH16 (see below for synonymy)
`--+--D. platycephalus (Günther 1873)DMH16, FG06 (see below for synonymy)
`--+--D. verrucosus (Tyler & Martin 1977)DMH16, FG06 (see below for synonymy)
`--+--‘Cyclorana’ occidentalis Anstis, Price et al. 2016AP16
`--+--+--D. alboguttatus (Günther 1867)DMH1, FG06 (see below for synonymy)
| `--D. brevipes (Peters 1871)DMH16, FG06 (see below for synonymy)
`--+--D. cryptotis (Tyler & Martin 1977)DMH16, C18 (see below for synonymy)
`--+--+--D. maculosus (Tyler & Martin 1977)DMH16, FG06 (see below for synonymy)
| `--+--D. longipes (Tyler & Martin 1977)DMH16, FG06 (see below for synonymy)
| `--D. maini (Tyler & Martin 1977)DMH16, FG06 (see below for synonymy)
`--+--D. manya (van Buerden & McDonald 1980)DMH16, C18 (see below for synonymy)
`--+--D. cultripes (Parker 1940)DMH16, FG06 (see below for synonymy)
`--D. vagitus (Tyler, Davies & Martin 1981)DMH16, FG06 (see below for synonymy)

Dryopsophus Fitzinger 1843 [incl. Brendanura Wells & Wellington 1985, Chirodryas Keferstein 1867, Chiroleptes Günther 1859 non Kirby 1837, Cyclorana Steindachner 1867, Euscelis Fitzinger 1843 non Brulié 1832, Fanchonia Werner 1893, Mitrolysis Cope 1889, Mosleyia Wells & Wellington 1985, Neophracops Wells & Wellington 1985, Pelodryas Günther 1859, Phractops Peters 1867]DMH16

Dryopsophus alboguttatus (Günther 1867)DMH1, FG06 [=Chiroleptes alboguttatusDMH16, *Brendanura alboguttataDMH16, Litoria (Cyclorana) alboguttataFG06, *Mitrolysis alboguttatusDMH16]

Dryopsophus aureus (Lesson 1829)DMH16, C18 [=Rana aureaDMH16, Litoria aureaPW11; incl. *Fanchonia elegans Werner 1893DMH16]

Dryopsophus australis (Gray 1842)DMH16 [=Alytes australisDMH16, *Chiroleptes australisDMH16, Litoria (Cyclorana) australisFG06]

Dryopsophus brevipes (Peters 1871)DMH16, FG06 [=Litoria (Cyclorana) brevipesFG06, Phractops brevipesF13]

Dryopsophus cryptotis (Tyler & Martin 1977)DMH16, C18 [=Cyclorana cryptotisAP16, Litoria cryptotisDP12]

Dryopsophus cultripes (Parker 1940)DMH16, FG06 [=Cyclorana cultripesPW11, Litoria (Cyclorana) cultripesFG06]

Dryopsophus lesueurii (Duméril & Bibron 1841)DMH16 [=Hyla lesueuriiDMH16, *Euscelis lesueuriiDMH16, Litoria lesueuriPW11]

Dryopsophus longipes (Tyler & Martin 1977)DMH16, FG06 [=Cyclorana longipesAP16, Litoria (Cyclorana) longipesFG06]

Dryopsophus maculosus (Tyler & Martin 1977)DMH16, FG06 [=Cyclorana maculosaAP16, Litoria (Cyclorana) maculosaFG06]

Dryopsophus maini (Tyler & Martin 1977)DMH16, FG06 [=Cyclorana maini AP16, Litoria (Cyclorana) mainiFG06]

Dryopsophus manya (van Buerden & McDonald 1980)DMH16, C18 [=Cyclorana manyaPW11, Litoria (Cyclorana) manyaFG06]

Dryopsophus novaehollandiae (Steindachner 1867)DMH16 [=*Cyclorana novaehollandiaeDMH16, Litoria (Cyclorana) novaehollandiaeFG06; incl. *Phractops alutaceus Peters 1867DMH16]

Dryopsophus platycephalus (Günther 1873)DMH16, FG06 [=Chiroleptes platycephalusAP16, Litoria (Cyclorana) platycephalaFG06, *Neophacops platycephalusDMH16; incl. Cyclorana slevini Loveridge 1950AP16]

Dryopsophus raniformis (Keferstein 1867)DMH16, C18 [=*Chirodryas raniformisDMH16, Litoria aurea raniformisBC06]

Dryopsophus vagitus (Tyler, Davies & Martin 1981)DMH16, FG06 [=Cyclorana vagitaPW11, Litoria (Cyclorana) vagitusFG06]

Dryopsophus verrucosus (Tyler & Martin 1977)DMH16, FG06 [=Cyclorana verrucosaAP16, Litoria (Cyclorana) verrucosaFG06]

Nyctimystes infrafrenatus (Günther 1867)DMH16 [=Hyla infrafrenataDMH16, Litoria infrafrenataPW11, *Sandyrana infrafrenataDMH16]

Nyctimystes tyleri Zweifel 1983 non Litoria tyleri Martin, Watson et al. 1979 (not preoc. if in dif. gen.)DMH16, FG06 [=Litoria michaeltytleri Frost, Grant et al. 2006FG06]

*Type species of generic name indicated


[AP16] Anstis, M., L. C. Price, J. D. Roberts, S. R. Catalano, H. B. Hines, P. Doughty & S. C. Donnellan. 2016. Revision of the water-holding frogs, Cyclorana platycephala (Anura: Hylidae), from arid Australia, including a description of a new species. Zootaxa 4126 (4): 451–479.

[BC06] Burns, E. L., & D. M. Crayn. 2006. Phylogenetics and evolution of bell frogs (Litoria aurea species-group, Anura: Hylidae) based on mitochondrial ND4 sequences. Molecular Phylogenetics and Evolution 39: 573–579.

[C18] Cogger, H. G. 2018. Reptiles and Amphibians of Australia updated 7th ed. CSIRO Publishing: Collingwood.

[DAP09] Doughty, P., M. Anstis & L. C. Price. 2009. A new species of Crinia (Anura: Myobatrachidae) from the high rainfall zone of the northwest Kimberley, Western Australia. Records of the Western Australian Museum 25 (2): 127–144.

[DP12] Doughty, P., R. Palmer, M. Cowan & D. J. Pearson. 2012. Biogeographic patterns of frogs of the Kimberley islands, Western Australia. Records of the Western Australian Museum Supplement 81: 109–124.

[DMH16] Duellman, W. E., A. B. Marion & S. B. Hedges. 2016. Phylogenetics, classification, and biogeography of the treefrogs (Amphibia: Anura: Arboranae). Zootaxa 4104 (1): 1–109.

[FB17] Feng, Y.-J., D. C. Blackburn, D. Liang, D. M. Hillis, D. B. Wake, D. C. Cannatella & P. Zhang. 2017. Phylogenomics reveals rapid, simultaneous diversification of three major clades of Gondwanan frogs at the Cretaceous–Paleogene boundary. Proceedings of the National Academy of Sciences of the USA 114 (29): E5864–E5870.

[FG06] Frost, D. R., T. Grant, J. Faivovich, R. H. Bain, A. Haas, C. F. B. Haddad, R. O. de Sá, A. Channing, M. Wilkinson, S. C. Donnellan, C. J. Raxworthy, J. A. Campbell, B. L. Blotto, P. Moler, R. C. Drewes, R. A. Nussbaum, J. D. Lynch, D. M. Green & W. C. Wheeler. 2006. The amphibian tree of life. Bulletin of the American Museum of Natural History 297: 1–370.

[F13] Fry, D. B. 1913. On a Varanus and a frog from Burnett River, Queensland, and a revision of the variations in Limnodynastes dorsalis, Gray. Records of the Australian Museum 10 (2): 17–34, pls 1–3.

[PW11] Pyron, R. A., & J. J. Wiens. 2011. A large-scale phylogeny of Amphibia including over 2800 species, and a revised classification of extant frogs, salamanders, and caecilians. Molecular Phylogenetics and Evolution 61: 543–583.

Tracy, C. R., S. J. Reynolds, L. McArthur, C. R. Tracy & K. A. Christian. 2007. Ecology of aestivation in a cocoon-forming frog, Cyclorana australis (Hylidae). Copeia 2007 (4): 901–912.

Withers, P. C. 1995. Cocoon formation and structure in the aestivating Australian desert frogs, Neobatrachus and Cyclorana. Australian Journal of Zoology 43: 429–441.

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