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Northern Red-eyed Tree Frog
Photo: C & D
Frith
Australian Tropical
Reptiles & Frogs
Northern Red-eyed Tree Frog: Litoria xanthomera
- Bright leaf - emerald or lime green above, and white to lemon yellow or orange
below.
- Hind side of thighs brilliant orange.
- Golden eyes with bright orange outer rings.
Habitat:
- Coastal rainforest areas of North Eastern Queensland.
- Usually encountered after rain.
Size:
- The average adult length of the
yellow-thigh Tree-frog is sixty-five
millimetres.
Call:
- Often call from shrubs and lower branches or
trees.
- The calls last for nine to twelve hours
- Each call is approximately one to two seconds long
- Calls are drawn out "Aaaarrkk" with each series
alternated with several short "Chirrups"
Additional Information:
This frog is without doubt one of the most colourful frogs in Australia and
certainly within the Wet Tropics. I have had a close association with studies on
this frog beginning in the mid-1970's when I collected specimens on the Atherton
Tablelands. Prior to these collections only a single individual had been noted
from the north Queensland area in the frog literature.
In 1974 while conducting fauna surveys at Eungella National Park near Mackay
I collected similar frogs. Much to my astonishment the Eungella animals were
smaller than those in the Wet Tropics and south-east Queensland and
northern NewSouth Wales. At this time all populations were put in the species Litoria
chloris (Southern orange-eyed treefrog).
In collaboration with Dr Marg Davies of the University of Adelaide a study on
intraspecific variation in Litoria chloris was conducted and published in
1979. We found that the mid-east Queensland population from Conway National Park
near Proserpine to Bulburin State Forest near Miriam Vale were significantly
smaller from other populations to the north and south. The only character other
than size we could find to differentiate the Wet Tropics population from others
was the lack of a blue/purple colouration on the hidden area of the thigh
(orange in the Wet Tropics population) and a slight difference in head shape.
It was not until the mid-1980's and more field work and using biochemical
techniques were we able to provide additional evidence sufficient to justify
recognition of the Wet Tropics population as a distinct species, Litoria xanthomera.
The lack of significant divergence in call structure between populations is
perplexing despite differentiation in morphology, genetic data and phenotype.
Recent studies by Beardsell in 1989 produced hybrids between L. xanthomera and
L. chloris, with offspring having deformities indicating the species were
distinct.
When collecting the holotype of L. xanthomera in 1980 I made sure it was
from a national park where the type locality would be least likely to be
destroyed and enabling topotypic material to be obtained at a later date for
future research if required. The type locality is in Henrietta Creek adjacent to
the location where Goolagan's Creek meets it. The tree branch from which the
holotype was collected (and its call recorded) is still there today despite a
fright I had when the Palmerston Highway was being widened.
Script courtesy of the Tablelands
Frog Club Inc.
Natural History Notes.
Litoria xanthomera is found from the Bluewater Range near Townsville
to the Big Tableland on the northern edge of the Wet Tropics Biogeographic
Region. Altitude ranges from 20 to 1300 m with most records above 200 m.
The name xanthomera is derived from the Greek xanthos for orange
and mera for thigh. In life the frog is a brilliant lime green dorsally
with ventro-lateral and ventral body pigmentation yellow/orange. The thighs are
brilliant orange. The eye is bright orange.
The frog has obvious finger and toe discs with fingers approximately
three-quarters webbed and toes nearly fully webbed. The snout and canthus
rostralis (the area between the eye and nostrils) are rounded in profile.
Females range in size from 4355 mm and males 40-56 mm. Females on average are
slightly larger than males. Amplexus (mating position) is axillary.
The call of L. xanthomera is a growl increasing in pitch (with a dominant
frequency of 3000 Hz) and ending in a series of trills. Choruses can be quite
large during heavy summer rain around pools adjacent to streams or waterholes
(including roadside ditches and quarries) in or near rainforest.
The egg mass is a clear, flat jelly-like mass with pigmented eggs. About 800 to
1500 eggs are laid. Fertilised eggs sink to the bottom of the pool soon after
laying. Time to hatching of tadpoles is dependant on water temperature. Eggs
laid in spring (should we get rain) take longer to hatch than those laid in
January. The tadpole is a typical lentic (pool) form with little pigmentation in
the tail and shallow tail fins.
Habitat is rainforest or adjacent wet sclerophyll forest with rainforest
elements. In our area L. xanthomera has been found at Lake Eacham and the
Crater National Parks and in the adjacent state forests. I have never found any
record from Lake Barrine National Park however this may be a reflection of
search effort in suitable conditions. I would be most interested to receive any
records of coastal lowland populations especially around Mission Beach, Mossman
and Cape Tribulation.
Additional studies on egg numbers, tadpole behaviour and survivorship, predation
and microhabitat preferences away from breeding pools needs to be conducted.
Script courtesy of the Tablelands
Frog Club Inc.
References
Davies, M. and McDonald, K.R. 1979. A study of intraspecific variation in the
green tree frog Litoria chloris (Boulenger) (Hylidae). Australian
Zoologist 20 (4) 347-359.
Davies, M., McDonald, K.R. & Adams, M. 1986. A new species of green tree
frog from Queensland, Australia (Anura Hylidae). Proceedings of the Royal
Society of Victoria 98 : 63-71.
Beardsell, G.R. 1989. Hybridisation of Litoria chloris and L.
xanthomera (Anura Hylidae). Transactions of the Royal Society of South
Australia 113 : 221-224.
McDonald, K.R. 1992. Distribution patterns and conservation status of north
Queensland rainforest frogs. Conservation Technical Report 1. Queensland.
Department of Environment and Heritage, Brisbane.
Southern
Red-eyed Tree Frogs of the Lamington National Park.
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