blue Pelophylax near Toulouse

[Pierre-Yves Vaucher]

Hi,
what do you think about this picture of blue Pelophylax sp. taken on the south of Toulouse, near Saint Gaudens ?
Less of xhantophores like blue Hyla meridionalis ?

other pictures on:
http://www.batraciens-reptiles.com/foru ... 28&p=13602

[Michal Szkudlarek]

Lack of golden iris suggests alampism (guanophores absence), but back should have been darker then. Whereas the back color suggests lack of lipidophores-

[Pierre-Yves Vaucher]

[Sandra Panienka]

Very cool, wish I would find a blue Pelophylax. The blue coloration is caused by reflection/scattering of light with short wavelengths from guanine platelets in the iridophore layer of the chromatophore unit in the frog's dermis when xantophores are missing. Günther (1990) has a nice description of different color anomalies in water frogs, even mentions some authors that described some finds of individuals with melanistic irises, it seems to be quiet rare.

[Pierre-Yves Vaucher]

Thanks Sandra, I put your explanation in my forum. Translation with google.

[Jeroen Speybroeck]

Look at the eye of this female... (not damaged or similar = other side was exactly the same)

green toads from Sicily (most likely Bufo (Pseudepidalea/Bufotes/...) (viridis) balearicus, to assault you all with the most crazy way to name it...)


I seem to remember some explanation, but I forgot - most likely in line with what Sandra wrote(?).

[Pierre-Yves Vaucher]

the lack of yellow pigments do why the pupil seems to take all the place in the eye (sorry for my english...) ?
For my very very old school and mentality, un crapaud, a toad, ein Kröte will be always BUFO !
= Bufo viridis or Bufo siculus

[Tom Hoogesteger]

I have found a Pelophylax just like that (first pic) in the Netherlands in 1994.

For my very very old school and mentality, un crapaud, a toad, ein Kröte will be always BUFO !
= Bufo viridis or Bufo siculus

I agree.

[Sandra Panienka]

This is the literature that Günther (1990) lists within his paragraph of Pelophylax spec. with melanistic eyes. Does anyone have access to any of this, especially the french stuff? I'd really love to read it.

Rostand (1953): Sur l’anomalie Iris brun chez Rana esculenta L. et chez Rana temporaria L. – C. R. Ac. Sci. (237) 762-764.
Rostand (1958): Les anomalies des Amphibiens Anoures
Dubois (1968): Sur deux anomalies de la grenouille verte (Rana esculenta). Bull. Soc. Linn. (37) 316-310.
Dubois (1979): Anomalies and mutations in natural populations of the Rana „esculenta“ complex. Mitt. Zool. Mus. Berlin (55) 59-87.
Rostand & Darré (1970): Une mutation de Rana esculenta: la Grenouille aux yeux noir. C. R. Ac. Sci. (271) 1414-1415.
Dubois & Vachard (1971): Sur une anomalie pigmentaire de la grenouille verte (Rana esculenta) et de quelques autres amphibiens anoures et urodeles. Bull. Soc. Linn. (40) 40-52
Dalton & Hoerter (1974): Patterns of purine synthesis related to iridophore development in the wild type, melanoid, and axanthi strains of the Mexican Axolotl, Ambystoma mexicanum. Developm. Biol. (36) 245-251.

For anybody who is interested in that chromatophore unit stuff within the amphiban dermis, I can recommend the "Biology of Amphibians" book by Duellman and Trueb; they explain it a bit better and more in detail than Günther does.

[Mario Schweiger]

If anyone has access to these papers,mentioned by Sandra, please mail them also to admin(at)fieldherping.eu, I will upload them into the DB.
Thanks

Mario