Crested newt's white-sheened tail...

[tj]

What does it mean when a crested develops a white sheen in its tail like this? I am used to this happening with Cynops and Paramesotriton, but haven't noticed it in Triturus before. But then I've had very little experience with this genus. I thought the male only enters into its breeding mode when it develops a crest...
Tim

 

[tj]

 

[jennifer]

The white sheen is part of "breeding mode". Looks like he's starting to get a crest too. They may also get some white coloration in the area just behind the mouth. Watch out - if they start to lay eggs, you could be up to your ears in baby cresteds

 

[aaron]

I would like to add that I've found a very faint sheen in all of my crested males year round. It intensifies greatly in a time of breeding.

~Aaron

 

[john]

Those look like carnifex?

 

[aaron]

Actually, I was thinking karelinii, although my monitor doesn't display colors correctly and I could be wrong.

~Aaron

 

[leonardo]

I think they are karelinii too!
carnifex is rather different an often has orangish belly (not yellow) with bigger black blotches...also the dorsal coloration is different from carnifex
bye
Leo

 

[davidnash]

My guess with the yellow belly and black and grey bodies would be cristasus

 

[john]

Nah, Jen and Aaron are probably right - I think it's Triturus karelinii now too. It might be carnifex, but definitely not Triturus cristatus.

 

[tj]

Thanks everybody. Never really intended to breed my cresteds since Asian newts are my main interest, but looks like they may have made up their own little minds!

I have four in all. I've only ever seen cresteds being sold here in Japan as either southern or northern, and species names are not usually given.

I bought two as northern and two as southern, but later was told the southerners were probably actually northerners or something else. They all look the same to me.

Griffiths describes carnifex as following:

"Upper surface is dark brown with black spots. Little or no white stippling on the flanks. Throat usually yellow and black with white stippling. Belly is orange with large, rounded blotches. Females and juveniles frequently have a conspicous yellow stripe running along the back."

And cristatus:

"Dark brown, warty body, with black spots and conspicuous white stippling on flanks and legs. Throat is dark with white stippling. Belly is yellow/orange with irregular black blotches, which are most abundant towards the anterior end."

Here are some more photos to help solve the mystery:

 

[john]

OK, I give up!

 

[tj]

Hmmmm...

karelinii:

"Body is dark brown with black spots. Some white stippling on the flanks, with more conspicuous whitish markings on the cheeks. Belly is orange with many small or medium-sized black spots; unlike other crested newts, the belly coloration continues on to the throat."

Judging from their throat coloration, I guess that would make them karelinii, although as you can see there is one whose throat color becomes white.

But they look more yellow than orange...

Mystery solved...?

 

[tj]

And finally, here are a couple "action shots" from last year that also might help in identification:

 

[aaron]

I'm not sure if these are all the same animals, but the far bottom picture is T. carnifex.

~Aaron

 

[tj]

Thanks Aaron. What gives it away in being carnifex?

Perhaps I shouldn't have added the last two pics because they may muddle things. Truth be told, I started out last year with six

, one of which escaped and was never found, while another died mysteriously. I should have confined the scope of my query to the current four...

The male in the last pic seems too dark and brownish to be one of the surviving four, though I don't know if the color naturally changes along with development of the crest. But as can be seen in the second-to-last pic, the belly markings are the same (note: that's not his tail but the tail of the female newt behind him!)

Come to think of it, I the white sheen is prominant in that last pic. In my original posting, what I meant to ask was whether it was normal for a male to develop this sheen even in the absence of a crest. But it was subsequently pointed out to me that it seems to be developing one.

Ah, to think that one of these days I'll have reached a level where I'll be able to make educated guesses too!

 

[aaron]

:-D You are correct, the body color will commonly change when the crest develops. The think that gave it away to me would be the brownish color. I've found that my karelinii stay a light grey color. The cristatus generally will stay dark, dark, grey. Carnifex and dobrogicus both turn a brownish color, but I don't think I'm qualified to swear to either dobrogicus or carnifex. This said, I must retract the fact that they are carnifex, because it's possible that they are dobrogicus-in which case I'll be emailing you about some juvies in spring :-D.

~Aaron

 

[caleb]

I'd agree that they're karelinii- the throat colour is a dead giveaway- when Griffiths says 'belly coloration continues on to the throat' he means that the throat is yellow/orange with dark spots, like the belly. The other three crested newt species have a dark throat with white speckles.

The grey-green spots on the back that you can see in the first photo seem to be characteristic of the Ukrainian karelinii imported over the last few years- I'm not sure if Balkan or Turkish ones have this, but I've not seen it on the other three species.

On the subject of the belly colour- this can change a lot with diet, just as in fire-bellied toads (Bombina). Captive bred crested newts are often much more yellow than wild-caught ones, as they get less colour from their diet. I've seen belly colour of crested newts in the UK from yellow to orange to red.

 

[aaron]

What foods effect the belly color, Caleb?

Thanks,
~Aaron

 

[caleb]

Hi Aaron.

Foods that can make the belly colour more red include Daphnia, Gammarus (freshwater shrimp) and bloodworm.

Colouring in various birds and fish (e.g. neon tetras) is also diet dependent. You can get fish and bird food which improves red colouring- you might try adding this to the diet of your livefood.

The main chemical group responsible for this colouring is the carotenes- if you can get pure canthaxanthin (which is a carotene), this is supposed to be very good for improving Bombina belly colour. Canthaxanthin is used in tanning pills (so has a similar effect on human skin). Beta-carotene is available as a dietary supplement, so these are both things you might also consider feeding to your livefood (probably wise to check for any other ingredients first!)

The reason the colour accumulates is that carotenes are much more soluble in fats and oils than in water, so they stay in the body, rather than being lost with waste water.

They are gradually lost, however, so you'd have to keep feeding coloured food to keep the colour.

 

[john]

Hi Caleb,
<blockquote><hr size=0><!-quote-!><font size=1>quote:</font>

Foods that can make the belly colour more red include Daphnia, Gammarus (freshwater shrimp) and bloodworm.<!-/quote-!><hr size=0></blockquote>
Leaving the first two aside, you're incorrect about bloodworms. A study by Leitch (1916) showed that Chironomus mosquito larvae (bloodworms for those that don't know) are by weight approximately 50% blood. Unlike a lot of arthropods, they use haemoglobin rather than haemocyanin as their respiratory protein. That's where the bright red colour comes from (oyxgen coordinated to the iron centre in haemoglobin) rather than a carotene, of which the bloodworm has none as far as I'm aware.

You're perfectly right in everything else you've said though.

All the best.