Viridescens or louisianensis?

[Niels D]

I know that most import of Notophthalmus to Europe is louisianensis. I've read that you can tell louisianensis apart from N.v.viridescens if they're efts don't turn bright red and when their red spots are inclompletely ringed with black. I've been told that my animals are louisianensis, but I want to make sure if that's true. Is it possible to tell them apart when you look at the spots and if so, can anyone tell me if these animals are louisianensis?

 

[FrogEyes]

I'd say they're louisianensis, but the genetic and morphological differences do not match in many areas. In addition, the red eft stage doesn't follow subspecies differences, but rather is somewhat local. I think eft COLOR tends to follow subspecies, but presence or absence of the eft is local.

 

[Niels D]

The offspring remainded mostly green in the eft stage. Some had a dull orange glow, but green all the same. Some lack red spots entirely. Guess it's louisianensis indeed. Thanks for the reply!

 

[Azhael]

You have to consider that the red spots and quite possibly the overall red colouration will not develop unless the diet is rich in carotenoids. I suspect, without them, efts of any subspecies will look greenish.

 

[Niels D]

I've tried carotenoid powder, which I also use to colour our H.orientalis and B.orientalis offspring. I've started to use this, because of the fact that the spots of the efts remain yellow if I don't (see picture). A ridiculously small amount is enough to colour those spots and bellies brightly red. If that doesn't turn an eft red than I guess a diet of crustaceans doesn't either.

See difference between yellow and red spots:

 

[Azhael]

In that case ignore my post xDD

 

[Niels D]

Your point (as always) was a good one, but I didn't give you all the information. :crazy: For other people who are using carotenoid powder (mostly used by bird keepers) for amphibians: You need a very small amount and when the result is good you don't have to use it ever again. There are no cases of an overdose to my knowledge when it comes to amphibians. Still it's advisable not to use a lot, especially because you don't need that much.

 

[slowfoot]

Just to further confuse the issue... I've never used any sort of carotenoid-based supplement but my efts' spots just seem to turn naturally from yellow to red when they mature. I don't think it's actually needed. I do feed a lot of bloodworms, though, so that might do the trick.

 

[Azhael]

There must be something else. Bloodworms have a low content of carotenoids, their vibrant red is due to haemoglobin which does nothing for the newt´s colour.

I had two groups of CB N.v.viridescens, one which i received as newly morphs (still with gill remnants) and another composed of juveniles of various sizes. The morphs never received any carotenoid rich foods and never developed any red whatsoever (although admitedly, only one survived until i gave them away to a friend). The bigger juveniles were very deep red when i received them, and from what i got from the breeder, it was due to a diet rich in crustaceans.

Niels, you are too kind. With regards to overdose, i heard rumours about them when people were using Vitamin A as the source (which apparently causes liver damage), but since commercial products started using astaxanthin and canthaxanthin i haven´t heard of overdose rumours anymore. Still, as you said, very small amounts are required at the right moment in development to produce spectacular results.

 

[slowfoot]

All of mine had spots that turned red when they reached adulthood.

 

[Azhael]

Is there anything in their diet that could account for it?

 

[slowfoot]

I don't think so. Everyone ate just daphnia, bloodworms, and earthworms.

 

[Azhael]

Ah, there you go, Daphnia can account for the carotenes. Even if it´s a small part of the diet, the effect is cumulative.

 

[Niels D]

Some species of Daphnia contain a lot more carotenoids than other. The ones I can gather are black ones and I am convinced that these animals contain less. That's why the powder comes in handy. The first time I bred them I raised one noto fully aquatic and he could eat Daphnia a lot longer than it's siblings. This one got red spots all on it's own. I'm going to raise all juveniles I got at the moment fully aquatic, because the one that was raised this way has given me the offspring I have now and it's an animal of 2011.

 

[caleb]

Bloodworms have a low content of carotenoids, their vibrant red is due to haemoglobin which does nothing for the newt´s colour.

This is true, but it's possible that the bloodworms sold in the fish trade have pigments added to them. The ones I buy come in pink water... (and they do seem to have a small effect on my newts' colour).

Some species of Daphnia contain a lot more carotenoids than other. The ones I can gather are black ones and I am convinced that these animals contain less.

You have to remember that Daphnia also get their carotenoids from their diet, just like amphibians do. I include spirulina powder in the food for my Daphnia culture to try and maximise their carotenoid content.

 

[Niels D]

It also depends on the light so it seems:
Carotenoids in Daphnia