Wednesday, 19 May 2010

Caudata

Yesterday we had the anurans (frogs and toads). Now its the turn of the newts and salamanders to take the spotlight. Order Caudata; Class Amphibia; Phylum Chordata



Alpine newt larva (about 2 days old)
Ichthyosaura alpestris (Laurenti, 1768) - Salamandridae
Hatched from eggs at home
June 2008

This species has gone through a couple of significant name changes in the last couple of years. For a long while it was lumped into the genus Triturus with all other European newts, but was placed into its own genus, Mesotriton, a couple of years ago. It turns out that the generic name Ichthyosaura was erected for this species some time before Mesotriton, so that name gets priority. Taxonomy is weird, I told you.



Male palmate newt (top) and male smooth newt
Lissotriton helveticus Razoumousky, 1789 / L. vulgaris (Linnaeus, 1758) - Salamandridae
Wild caught in Epping Forest, Essex
March 2009

The main difference between these two native British species can be seen clearly in this photograph. While smooth newts occasionally have enlarged feet during the breeding season, they are never black, unlike the male palmate newt.



Male great crested newt
Triturus cristatus (Laurenti, 1768) - Salamandridae
Wild in Epping Forest
March 2009

Don't try this at home. You need to have a licence or be in the company of someone with a licence to hold a great crested newt in the UK (I was the latter). Their alternate name of 'warty newt' is quite apt, as they are distinctly lumpy to the touch. They are the biggest of the British newts, and by far the most impressive.



Japanese fire-bellied newt
Cynops pyrrhogaster (Boie, 1826) - Salamandridae
London Zoo
December 2009

This species, and its close relative from mainland Asia, the Chinese fire-bellied newt (C. orientalis) are popular pets, although this species is larger and apparently more aggressive, and the two species should not be kept together.



Immature smooth newt
Lissotriton vulgaris
Wild in Epping Forest
March 2009

I dug up this little guy in the undergrowth, probably just rousing from its winter hibernation. Smooth newts are the most common of the newts in the southeast of England and in much of the UK and western Europe.



Himalayan crocodile newt
Tylototriton verrucosus Anderson, 1871 - Salamandridae
London Zoo
December 2009

A bit of an exaggeration to liken a salamander to a crocodile, but here's the crocodile newt. There are other members of the genus, distributed in parts of Asia, with bright orange markings.



Male smooth newt
Lissotriton vulgaris
Wild in Epping Forest
March 2009

The male smooth newt has an orange belly and jagged crest in the breeding season, but neither feature is as pronounced as in the great crested newt.



Male palmate newt
Lissotriton helveticus
Wild in Epping Forest
March 2009

The male palmate newt in the breeding season has the black hind feet and filamentous ending to the tail. The crest is lower than the smooth newt's and the belly is pinker and with less spots.



Female smooth newt
Lissotriton vulgaris
Wild in Epping Forest
March 2009

Female smooth newts have orange bellies with black spots - this individual has a pea mussel (Pisidium sp.) stuck to its right forelimb.



Female palmate newt
Lissotriton helveticus
Wild in Epping Forest
March 2009

Female palmates are hard to tell from smooths, even during the breeding season, but the throat is pink and with very few spots.



Male alpine newt
Ichthyosaura alpestris
At home in Enfield
June 2008

I tried keeping alpine newts for a brief spell a couple of summers ago. Alpine newts like cool water, and while creating a heated environment in a tank is easy, cooling an aquarium is not. The pair of newts weren't eating, despite having all the bloodworms they could ever want. I gave them back to the pet shop I acquired them from, and stuck to axolotls, xenopus frogs, and catfish.



Female alpine newt
Ichthyosaura alpestris
At home in Enfield
June 2008

I keep typing 'Ichthyostega' instead of 'Ichthyosaura'. That blue stuff on the female above is the tissue paper that the male is sitting on in the previous photo.



Giant salamander skeleton
Andrias scheuchzeri (Holl, 1831) - Cryptobranchidae
Natural History Museum, London
September 2009

Does this look like a human skeleton to you? No, me neither. But early palaeontologists believed the remains of a giant salamander - closely related to todays giant salamanders of China and Japan, and the hellbender (Cryptobranchus alleghaniensis) of North America - to be those of the humans who lived before the great flood of biblical times. It was given the scientific name Homo diluvii testis, translating as 'evidence of a diluvian human'. When it was realized that it is infact an amphibian, not a human, it was given the new generic name Andrias, meaning 'image of man'.



Wild type axolotl
Ambystoma mexicanum (Shaw, 1789) - Ambystomidae
Temporary aquarium at home
March 2007

I kept axolotls for a period of four years. At one point, I had three, living together in harmony in the same aquarium - Slash, my golden axolotl (photo below), George who was white with dark eyes and red gills, and Mildred, the wild type who appears above. Mildred began to take chunks out of the other two - George lost most of three of his limbs and much of his gills and died a few months later; Slash's wounds were mostly superficial and healed well. When it became known to me that Mildred was a man-eater, I isolated her, and decided to sell her. Poor thing, she was a beauty really.



Golden axolotl
Ambystoma mexicanum
Aquarium at home
January 2005

Slash was my first axolotl, and the last to leave. Axolotls, in case you didn't know, are an excellent example of neoteny. This is commonly known as Peter Pan syndrome, where adults of breeding age take on physical characteristics of juveniles. In the case of the axolotl, it is basically a giant tadpole. They have some characteristics of tadpoles, such as gills and a fin on the tail, and others of adult salamanders, such as partial lungs, and legs. They can be forced to metamorphose into adults through hormonal injections.

I think I'll do squamates (lizards and snakes) next. Stay tuned!

3 comments:

Zach said...

Query: is the term "newt" paraphyletic, or are they really a separate branch from other salamanders? An amphibian version of porpoises, perhaps?

Mo Hassan said...

It's a completely paraphyletic term. Generally, members of the Salamandridae apart from the genus Salamandra are known as newts, and I believe there are some North American species in the Plethodontidae which are also called newts.

The term 'porpoise' in the UK strictly refers to the Phocoenidae, as opposed to the US usage which sometimes overlaps with dolphins.

Mattias Müller said...

Nice page and Point of viewing (from a palaeontological biological perpective). You are though wrong about Newts being paraphyletic. The term is actually monophyletic. Look at a clade of Salamandridae and you see yourself. No lungless are ever called Newts. This is unintentionally but is a monophyletic clade nevertheless if one should use such Words for vernacular names.