4 replies to this topic

[LaurieAG]

I would never have believed that there was a salt water frog that looked much like a Green tree frog until I saw these little frogs in my pool the other day. I initially thought they might be cane toads until I had a closer look and noticed that they had smooth skin and spots of gold along their sides. While the pool pump hasn't been working for a couple of months (no chlorination) and we have had quite a bit of rain lately the pool is still very salty the juveniles like to sit about a metre down before they come out.

 

Freycinet's Blue Frog was originally discovered by Louis de Freycinet during an expedition led by D’Entrecasteaux in 1791.

 

The drawing here from the State Library of NSW, painted circa 1790's, looks very much like the juvenile frogs in my pool and the adults that also live near near my fathers saltwater pool.

http://acms.sl.nsw.g...x?itemID=411901#

 

The following link refers to a Green Tree frog that was pickled in alcohol that appeared blue as the green pigment was dissolved. These frogs have black/blue skin but are alive and kicking.

 

http://www.aqob.com....ious_Blue_Frogs

 

If you know anything about osmosis through semi permeable membranes you'd know that they must have quite a high concentration of salt internally to be able to survive in these conditions.

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[LaurieAG]

As the Australian Green Tree frog is incorrectly called Litoria caerulea (Bleach Blue), I called this one Litoria caeruleum (means the same) to distinguish it. The original could possibly be called Litoria aureum viridi (gold/green) and this one Litoria aureum cæruleum (gold/blue).

If future offspring could return to gold/blue in fresh water the change would be reversible although the internal salt content change may only allow successful breeding with other blue frogs in salty water due to osmosis.

http://www.projectno...ttings/18385220

Edited by LaurieAG, 24 February 2013 - 01:18 PM.

[LaurieAG]

Actually that's Beach Blue with google translate and it seems that the original 1790's taxonomy was correct for the wrong reasons.

 

http://en.wikipedia....imal_coloration

 

Mechanisms of colour production in animals. Animal coloration may be the result of any combination of pigments, chromatophores, structural coloration and bioluminescence.
...

Coloration by Pigments. Many animals, including mammals, birds, and amphibians, are unable to synthesize most of the pigments that colour their fur or feathers, other than the brown or black melanins that give many mammals their earth tones.
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Variable coloration by chromatophores. Amphibians such as frogs have three kinds of star-shaped chromatophore cells in separate layers of their skin. The top layer contains 'xanthophores' with orange, red, or yellow pigments; the middle layer contains 'iridophores' with a silvery light-reflecting pigment; while the bottom layer contains 'melanophores' with dark melanin.

[LaurieAG]

Here are a few more images.

And some more. 

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[LaurieAG]

Here is a comparison for those who think they might be cane toads. I have only spotted 5 cane toad tadpoles in the pool all up compared with hundreds of Blue Tree frogs.

 

The cane toad tadpoles are much larger, are not blue in color, move very sluggishly and keep near the top in the fresher water. That's a ratio of around 2-3 % cane toads to blue tree frogs. 

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