Taxonomy

(Barker et al.,1995; James and Moritz, 2000; Kraus and Allen, 2004; Tyler and Davies 1978)

Litoria fallax did not achieve separate status from Litoria bicolor until 1969 and the two species are closely related.

L. fallax belongs to the species group known as the Bicolor Group. Members include the Australian species Litoria cooloolensis (discovered in 1974) and Litoria bicolor ; and New Guinea species. Litoria contrastens, Litoria longicrus,and Litoria mystax and perhaps Litoria bibonius from the Normandy Islands.

Phylogenical analysis within the species shows two distinct lineages separated by the McPherson Ranges.

Description

(Barker et al., 1995; Cogger, 1988; McDonald, 2000; Tyler, 1982; Tyler and Davies, 1978)

Litoria fallax is one of the smallest of the arboreal Litoria species. It is of slender build and has enlarged discs on its fingers. It is very similar in appearance to L. bicolor and is best differentiated, where possible, by call.

The smooth dorsum can range from completely green to completely brown or a mixture, in the form of a bronze or brown vertebral band or sometimes irregular dark spots present on the back. A white stripe extends from the corner of the jaw running beneath the eye to the shoulder area. From the nares to the eye there may be a bronzy stripe. The eye is heavily flecked with gold and the pupil is horizontal. tympanum is exposed and about half the size of the eye diameter. Orange coloration is present behind the thigh and on the groin area. Ventrum is uniformly white with a granular texture. The fingers only have slight webbing but the toe webbing is well developed.

Size (snout-vent). Females range between 25 and 32mm apx. with males smaller, from 22 to 26 mm. apx.

Adult

Call

( Barker et al., 1995; Cogger 1988; McDonald, 2000)

The sound of the call is similar to L. bicolor but the difference lies in the sequencing.
The call is described as an extended "wreeeek“ and then one or two short pip sounds. It is high pitched and repeated with an upwards inflection. Becoming familiar with this call by listening, however is an easier way to learn it.

Geographic range

(Barker et al., 1995;Cogger, 1988; James and Moritz, 2000; McDonald, 2000)

An eastern Australian species its range extends from south of the Normandy Gap (Daintree area) in Far North Queensland to the Hunter Valley in NSW. It is considered a coastal species but it crosses the Great Dividing Range. In areas where it overlaps with L. bicolor it is said to inhabit higher elevations, however on Magnetic Island both species exist in lowland areas.

Biology/physiology

(Amey and Grigg, 1995, Tyler and Davies, 1978)

Arboreal species such as Litoria fallax exhibit strong resistance to water loss, and have a cutaneous lipid layer which appears to provide an effective waterproofing method. In experiments that compared L. fallax to L. peroni , the former showed a markedly higher resistance to evaporative water loss. L. fallax's lipid layer is positioned differently, above the blood vessels in the skin whereas in L. peroni it is below.

L. fallax along with the other members of its species group has elongate and ossified intercalary structures. Alary processes are present on the hyoid plate.

Typical breeding habitat for this species on Magnetic Island

Habitat, Ecology Behaviour etc.

( Barker et al., 1995; Cogger, 1988; McDonald, 2000; Swan, 2001, Williams et al., 2000)

L. fallax is known as a coastal swamp-inhabiting species but is also often found in urban areas,and beside permanent waterholes and dams. Nocturnal, It is known to often rest in leaf axils by day in varied species such as pandanus and banana or pineapple plants.L.fallax does not seem to exhibit defensive postures or colouration displays as an Antipredator mechanism but does exude an odour of grass when under apparent threat. It does , however engage in 'hand waving or foot flagging behaviour between males ,which may be a territorial issue. In these encounters it is thought to be an appeasement gesture as it seems to be the losing frog in the confrontation that exhibits this before leaving.

Reproduction

(Anstis, 2002; Dziminski and Alford, 2005; Barker et al., 1995; Cogger, 1988; Lee and Jamieson,1993; McDonald, 2000; Swan, 2001; Tyler, 1994)

In the wet/dry tropics calling begins with the first summer rains in November/December, this species may bet-hedge by also calling late in the wet season when other species are finished (pers. Obs). At night, clustered on the tips of exposed reeds and low overhanging vegetation, in flooded areas, is a common place for calling males who will also call intermittently on overcast days. Where permanent water or when rain falls earlier, calling may last from October to April. Sperm length is apx. 16µm - body and 40µm - tail.

In separate clumps attached to vegetation about 250 eggs are laid. The size of the female has been shown to positively correlate to the yolk size of the eggs which may cause variation in time to metamorphosize, between clutches.

1 ,1, 1 /3 is the tooth row formula in tadpoles. Surface feeding tadpoles are easy to distinguish from species outside their group because of the high tail arch. They reach a body length of 14mm with a tail length to 42mm. Metamorphosis usually occurs within 100 -120 days (118days @ 20°C has been recorded). 9-13mm is the size of metamorphs.

References

Anstis, M (2003) Tadpoles of South-eastern Australia, Reed New Holland, Sydney, NSW

Amey, A.P. and Grigg, G.C. (1995) Lipid-reduced evaporative water loss in two arboreal hylid frogs,Comp. Biochem., I I I A: 2: 283-291.

Barker, J,Grigg, G. and Tyler, M.(1995) A Field Guide to Australian Frogs: Surrey, Beatty and Sons, NSW.

Cogger, H. G., 1988. "Reptiles and Amphibians of Australia ". Reed Books, N.S.W.

Dziminski, M.A.,i and Alford, R.A. (2005), Patterns and fitness consequences of intraclutch variation in egg
provisioning in tropical Australian frogs, Oecologia 146: 98–109

James, C. H. and Moritz, C., (2000), Intraspecific phylogeography in the sedge frog
Litoria fallax (Hylidae) indicates pre-Pleistocene vicariance of an
open forest species from eastern Australia, Molecular Ecology:9:349–358

Kraus, F. and Allen, A.(2004) Two New Treefrogs from Normandy Island, Papua New Guinea,Journal of Herpetology 38 (2):197-207

Lee, M.S.Y.and Jamieson ,B. G. M.,(1993), The ultrastructure of the spermatozoa of bufonid and hylid
frogs (Anura, Amphibia): implications for phylogeny and
fertilization biology, Zoologica Scripta, 22;3, :309-323.

McDonald, K., 2000, in "Wildlife of Tropical North Queensland" Eds. Ryan, M. & Burwood,.C.Pp.170-195 :Queensland Museum.

Swan, G.,(2001) Frogs of Australia,New Holland Publishers, Melbourne

Tyler M.J., (1994), Australian Frogs - A Natural History,Reed Books, Chatsworth, NSW.

Tyler M.J.and Davies, M. (1978)Species-groups within the Australopapuan Hylid Frog
Genus Eitovia Tschudi: Australian Journal of Zoology Supplementary Series No. 63 C.S.I.R.O

Williams, C., Brodie, Jr. E.,Tyler, M., Walker, S.,(2000) Antipredator Mechanisms of Australian Frogs
Journal of Herpetology: 34, : 3: pp. 431-443.

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