Tetrapod Zoology

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It’s not all dinosaurs, killer eagles, blue whales, vampires and giant feral cats you know… as planned, I did spend Wednesday evening out in the field looking for newts (for the purposes of this discussion, newt = any member of the amphibian clade Salamandridae that is aquatic during the breeding season). Admittedly ‘the field’ may not quite be the appropriate term, as the newts we were searching for were a rumoured population reported to inhabit an ornamental pond in the middle of Southampton city centre. It’s great, the way people look at you, as you march through an urban area with your torch, fishing net and boots….

However, we did find the newts and, despite my high hopes that we might discover a wayward population of introduced Bosca’s newt Lissotriton boscai or Italian newt L. italicus, they turned out to be one of our commonest species, the Smooth or Common newt L. vulgaris. It’s an attractive little beast and always fun to watch, especially at this time of year (when they’re breeding and in their aquatic phase). The ‘we’, by the way, is myself, Phil Budd and John Poland [see image below]: we all represent the Southampton Natural History Society (Phil is chairman), but John is also chairman of the Hampshire Amphibian & Reptile Group.

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It wasn’t exactly surprising to find that the colony consisted of Smooth newts. As I’ve now said several times (see Britain’s lost tree frogs and Hunting green lizards in Dorset), Britain is crap for reptiles and amphibians. We have just three newts, though one additional species is present here as an introduction (Banks 1989, Wisniewski 1989, Beebee & Griffiths 2000). Our biggest newt is the Great crested newt Triturus cristatus, sometimes termed the Northern crested newt by those outside of Britain, and referred to in shorthand as the GCN by those in the British herpetological community. Reaching 16 cm, it may be twice as big as a Smooth newt, and its dark brown colour, silvery tail flash, warty skin texture and enormous serrated dorsal frill make it unmistakable (females lack the tail flash and frill of course).

Occurring throughout northern Europe (but not Ireland or northern Scandinavia), it is most numerous in Britain where we not only have the highest number of breeding ponds (about 18,000 according to a 1989 estimate), but the biggest populations (a colony near Peterborough in Leicestershire apparently includes over 30,000 adults). Sadly however, it is clearly declining across its range and is thought to be the fastest-declining British amphibian or reptile. The 1981 Wildlife and Countryside Act (WCA) makes it illegal to harm, kill or trade in Great crested newts, to disturb, handle, possess or collect them, and to intentionally disturb the places where they occur. You need to hold a license to catch or handle them therefore. In practise however this doesn’t mean much, as not only do breeding pools get filled in by developers who are – allegedly – unaware of a newt colony’s presence, there are also loopholes (such as pre-existing planning applications) that allow the destruction of newt habitat (Griffiths 1996, Beebee & Griffiths 2000).

Europe’s newts are well known for their elaborate breeding appearance and complicated courtship rituals. Males may grow special fringes or webs on their toes, filaments at the tail tip, and elaborate dorsal crests, and they combine these features with brightly colored undersides. They only grow these secondary sexual characters after entering the water and resorb them when the breeding season ends. The sexual dimorphism present in European newts is among the most pronounced of all amphibians [adjacent GCN image from here].

Newt courtship is well known, well studied, and oft-recounted in herpetology books, so you may feel like you’ve heard the following all too many times before. During the breeding season, a male initiates courtship by pursuing or getting in front of a female; assuming she doesn’t swim away, he then begins displaying to her. He fans his crested tail in her direction, apparently in an effort to waft pheromones all over her, and as the display proceeds he may perform whipping, flicking, wiggling, rocking, and head-bobbing actions. Some of the postures adopted by the males of some species are known as ‘flamenco’, ‘cat-buckle’, ‘flurry’ and ‘whiplash’ (Arntzen & Sparreboom 1989: for more information on these display details go here). Some species perform hand-stands and present their bodies and crests in full lateral view to the female. The smaller newt species tend to use delicate, dextrous tail movements, while the big species use violent lashing of the tail: in the ‘whiplash’ action the male’s tail is repeatedly lashed across the female’s head and body. If the female remains interested, the male ends the display by turning away from the female and slowly moving off. She follows, her nose touching his tail, and he then releases a spermatophore – a sperm-filled gelatinous packet – on the substrate. The male then has to manipulate the female so that she continues moving forward, but doesn’t move so far forward that the spermatophore fails to contact her cloaca. All going well, contact is made and the spermatophore adheres.

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All of this highly visual displaying requires an uncluttered, open display area, and newts may therefore not be able to breed in ponds that become choked with vegetation. Having said that, the smaller species seem relatively well able to attract and display to females in well-vegetated ponds, and this probably explains why their crests are smaller and less flamboyant that those of the big species. Furthermore, some of the smaller species (including the Palmate, Italian and Bosca’s newt) seem to rely more on pheromones in courtship than the large species, and are equipped with longitudinal ridges on their bodies that seem to help direct the wafted pheromones. There is also no evidence that males among the smaller species make, or stick to, a special display stand: they apparently wander about the chosen pool, and may even move from pond to pond in quest of females [adjacent photo shows – I think – a female Palmate newt from a Southampton garden pond].

For the big flamboyant species things are different: they do require special display stands, and they may stick to, and defend, special open areas on the pond floor. The males not only display to females, but to each other, and in fact male vs male displays are more common than male-female displays in some species (Hedlund & Robertson 1989). Males may tussle with and bite one another over dispute for a display area. This territorial aggression and choice of open display areas means that newts might be classified as lek breeders: a lek is an aggregation of breeding males, attending by females primarily for the purposes of mating. Leks are well known for birds (such as grouse, manakins, hummingbirds and snipe) and are also formed by a few mammals, including Fallow deer Dama dama, some antelopes, Hammer-headed bat Hypsignathus monstrosus and Walrus Odobenus rosmarus (Hoglund & Alatalo 1995). They aren’t the preserve of mammals and birds, as various frogs, crabs, flies and assorted other animals lek too.

Not all male vs male interaction in newts is aggressive however: some of it is covert. In several species, including Smooth and Great crested newt, some males mimic females. They pretend to be interested in a displaying male and, like a sexually receptive female, wait transfixed by his display, and then follow him and snout-nudge his tail when he begins to move off for the spermatophore transfer. A female that was genuinely watching the displaying male may then be led away by the mimic, who then gets the female to absorb his spermatophore (Verrell 1984).

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After discovering the Smooth newt colony, we pressed on to another location to check the newt population there. For several reasons I will opt not to reveal the location’s name. Searching by torchlight around the edge of a large barren lake, we discovered that both Smooth and Palmate newts L. helveticus were present at the site. The Palmate newt is Britain’s smallest species (reaching 9.5 cm), though it’s not the smallest of all European newts, being exceeded by the 8-cm Italian newt L. italicus. Endemic to western Europe (though Ireland lucks out again, as does central and southern Portugal and Spain), breeding male Palmate newts possess only a very low, unserrated crest and possess black webbing on the hind feet and a filament at the tail-tip. Palmate newts also possess an unspotted pinkish throat and shallow grooves on the top of the head.

In the adjacent photo, we aren’t deliberately humiliating the Palmate newt that’s being handled, at least not intentionally, but examining its feet for signs of the metatarsal tubercle that is also diagnostic for this species.

Whether Britain’s herpetofauna is crap or not, I will maintain, as usual, that what little we have is still worth getting to know. I mean – come on – frill-crested amphibious salamanders that perform hand-stands and cat-buckle displays, waft pheromones over their breeding females, form leks, and indulge in ‘sexual interference’ (Verrell 1984). I’m sorry, but that’s amazing.

Refs – –

Arntzen, J. W. & Sparreboom, M. 1989. A phylogeny for the Old World newts, genus Triturus: biochemical behavioural data. Journal of Zoology 219, 645-664.

Banks, B. 1989. Alpine newts in north east England. British Herpetological Society Bulletin 30, 4-5.

Beebee, T. & Griffiths, R. 2000. Amphibians and Reptiles. HarperCollins, London.

Griffiths, R. A. 1996. Newts and Salamanders of Europe. T & A D Poyser, London.

Hedlund, L. & Robertson, J. G. M. 1989. Lekking behaviour in crested newts, Triturus cristatus. Ethology 80, 111-119.

Hoglund, J. & Alatalo, R. V. 1995. Leks. Princeton University Press, Princeton.

Verrell, P. A. 1984. Sexual interference and sexual defense in the smooth newt, Triturus vulgaris (Amphibia, Urodela, Salamandridae). Zeitschrift Fur Tierpsychologie 66, 242-254.

Wisniewski, P. J. 1989. Newts of the British Isles. Shire, Aylesbury.

Comments

#1 Raymond
March 9, 2007

First thing off the top of my head upon seeing the male greater crested newt pic,”Basilisk”.He’s very pretty.
#2 Tommy Tyrberg
March 9, 2007

Darren

If people give You a hard time when you go newting in the city You might try using a trick I learned from somebody who was doing a botanical survey of the central parts of a major city. He found that if he dressed in one of those orange overalls that roadworkers use plus a hardhat and gumboots and carried a clipboard with a bunch of papers he could go absolutely everywhere and examine anything without anybody ever questioning what he was doing.
#3 Richard Carter, FCD
March 9, 2007

Another excellent article, thanks.
#4 Mike Keesey
March 9, 2007

Somehow I can’t help but compare you to Gussie Fink-Nottle from P. G. Wodehouse’s “Jeeves and Wooster” stories….

Good stuff, though! Thanks for posting on the little guys (even if they don’t draw as many hits).
#5 Bruce J. Mohn
March 9, 2007

Hi Darren:

Great post as always. Had a question about your choice of night over day for collecting. Are the newts nocturnal in Britain or was there some other reason for collecting them at that time?

Here in the States I’ve always collected newts in the daytime, though have heard that the time for finding ambystomids is after dark.

Bruce
#6 Darren Naish
March 9, 2007

Thanks to you all for your nice comments.

Tommy: that’s excellent advice, I’ll discuss it with colleagues (some of whom do surveying work in far more ‘hostile’ areas than I do).

Mike: I’m not quite the teetotal bachelour that Gussie was, but my horn-rimmed spectacles certainly fit the bill Incidentally I first learnt of the newt crossover due to a line used by Stephen Fry’s version of Reginal Jeeves: when speaking of newts he describes them as belonging to the genus Molge (the name in use at the time).

Bruce: our newts are most active at night (though I’m not sure I’d describe them as nocturnal) and are way easier to find and observe then than during the day. Having said that, they are still findable in the day if you know how to find them (see photos in article).
#7 David Kelly
March 9, 2007

Is the established introduced species you refer to the Alpine Newt in the Edinburgh area?

David
#8 Will Baird
March 9, 2007

Great Post, Darren!

Any posts on Giant Salamanders[1] coming by chance?

(or therapsids, *needle*)

1. http://en.wikipedia.org/wiki/Giant_Salamander
#9 Allen Hazen
March 10, 2007

One zoological and one linguistic question:
–How closely related are tthese European things to the animals called “newts” in the United States: the American ones look like the “base model” of the animal in your photos (fthird and fourth photos look closest for the Eastern U.S. version, but it’s been some years since I’ve looked at them closely), but I don’t think they develope crests in the breeding season.
—Is the word “eft” used for anything in (standard, non-dialect) British English? (I believe it is etymologically related to “newt”, the initial “n” migrating back or forth to or from the article, as in “an adder,” which in the old days was “a nadder”: English “adder” is cognate with German “Natter.”) At least in parts of the U.S. (I think Western) there is something called a “red eft”: the red terrestrial phase of a newt, which changes back to green when it goes back in the waterr to breed.
#10 Darren Naish
March 10, 2007

Allen, thanks for your comment.

On affinities, ‘newt’ is simply an informal term for any amphibious salamandrid, and even then it’s not used across the board (e.g. sharp-ribbed salamanders are phylogenetically surrounded by ‘newts’). Phylogenetic studies generally indicate that European newts are closest to Asian emporer newts (Neurergus) and European brook salamanders, aka brook newts (Euproctus). The American newts Taricha and Notophthalmus are part of the same clade within Salamandridae as Triturus and its relatives, but are apparently not particularly close to them. Loads of Asian taxa (including the crocodile newts, paddle-tailed newts and fire-bellied newts) fill out the phylogenetic tree between the American taxa and the European ones, and studies disagree as to whether it is the European or American taxa that are more basal.

In Britain, the term eft is ‘officially’ used only for newt larvae, but in various places it is (I think) used as a dialectal term for all newts.
#11 David Marjanovi?
March 10, 2007

On the etymology of “adder”… that’s a lot more complicated. German has both Otter, which means “adder” (various viperids, most typically the Kreuzotter, Vipera berus), and Natter, which refers to “colubrids” that are not venomous (or at least not conspicuously so). I have read that these two words are related to each other, via a dialect somewhere in Germany where /nadr/ (“colubrid”) got misinterpreted as /n adr/ (acquired meaning “an adder”). That fails to explain the different vowels, though.

The quintessential Natter species are in Natrix, so I guess that’s where the words ultimately come from.
#12 KarenMcL
March 10, 2007

Hey Darrien – I didn’t know you were *interested* in American Politics. *wink* (And thanks for the Hat/Tip on Mating Newts.)
#13 Nick Pharris
March 11, 2007

David: I’m thinking adder and Natter are probably not directly from Lat. natrix (the change from t to d would be odd in a borrowing that old, plus there’s the issue of the feminine -ix suffix in the Latin form), but they could be related at the Indo-European level.
#14 Alan Kellogg
March 11, 2007

So natter about adders can get quite confusing.
#15 John Hutchinson
March 11, 2007

I have one lonely L. vulgaris in my ponds; wish I could bring it company (let alone add some crested newts to our habitat, which would be da bomb!). I haven’t seen it yet this year, but we do have a bumper crop of over 60 frogs and toads having a mating fiesta right now; by far the most ever.
#16 Darren Naish
March 11, 2007

John: where there is one newt, there are normally more…

I don’t have a pond where I live right now (a consequence of having a young child) but at one of my former residences we used to get 100-200 mating frogs every year (usually in early February). Then, in the early 1990s, they all died. ALL of them. Today that same pond is still devoid of breeding frogs. You’re pretty lucky then. As you know I’m sure, mass die-offs of frogs and toads have been occurring all around the world within the last 20 years; entire species have been lost.
#17 Brian
March 11, 2007

Not trying to make people jealous but in our pond, L. vulgaris is extremely common. In the past, we used to catch some by having a specially worked bottle with tubifex inside it in the pond for just half an hour. This usually resulted in at least 12 newts caught inside the bottle. Of course, we released them afterwards.

We used to identify individuals and I estimate we had (and still have) about 50 adults…thus not counting the larvae.

We haven’t done the bottle-trick in a while now, but we still regularly see the newts. A beautiful sight it is, to see them lazily swim to the surface and take a breath for air.

Since last year, we also have T. cristatus, though in a very small number as of yet.

As for the size of the pond, my guess is that it is 1,5 cubic meters at most, which goes to show the huge densities at which newts can occur.
#18 DDeden
March 11, 2007

Speaking of salamanders, here’s a robotetrapod sp. that can swim, crawl and walk… but can it hold it’s breath or breathe through it’s skin?

http://www.technewsworld.com/rsstory/56220.html

DDeden
#19 Randy
March 11, 2007

Here in the Bay Area of California an annual ritual for natural history enthusiasts is to go see the migrating and breeding newts in late February and early March. Depending on the localities you visit, one can see hundreds to thousands of newts in a single pond. These are Taricha torosa and Taricha granulosa. Of course the added thrill in handling one of these newts is that they can contain enough poison (specifically tetrodotoxin) to kill up to 12 humans. This is because they are in an evolutionary arms race with the garter snake, Thamnophis sirtalis. This system has been well-studied by the Brodie father & son team of herpetologists.
#20 Sordes
March 11, 2007

In our pond in the garden there is also a small population of T. alpestris, which has its origin in five larvae I introduced many years ago. The pond is not very big, only about 2,5m, but the newts thrieve in it and reproduce. At the beginning there was only one single female over several years, and a bunch of about 12 males or more, which consisted of the original introduced specimens and their young generation. The males really besieged the single female. In the last years some other females came to the pond, and there is also a single specimen of T. vulgaris in the pond, although I found also already some young terrestrial specimens of T. vulgaris in our garden (one of them had 6 toes on one foot), which are probably from the pond of our neighbours.
#21 Allen Hazen
March 11, 2007

On the etymological issue…
I should have done more homework before posting, I suppose. The only source I have handy is the “American Heritage Dictionary of Indo-European Roots”. (The “American Heritage Dictionary” is a good desk-size dictionary which– since it has American spellings– doesn’t sell well in the British Commonwealth. It’s original, 1969, edition had an appendix of reconstructed Indo-European words, listing their English descendants. What I have in my — Australian — office is a copy of the later publication of the appendix as a separate paperback.)

It gives “netr-” (long e) as its reconstruction of the Proto-Indo-European, giving “snake” as meaning. Reconstructed Proto-Germanic form “nethro-” (long e, long o). Anglo-Saxon form (actually attested: not just a reconstruction) “naedre” (the ae being a single letter, and long), giving rise to the modern English “adder”.

I assume the Latin natrix would be from the same Indo-European root (not mentioned since it doesn’t have an English derivative in the dictionary), but the Germanic forms are probably direct inheritances from Proto-I-E, not connected with the Latin.

The ENGLISH word “otter” (for a mustelid mammal) is unconnected: it is from the Indo-European wed- , which also gives us wet and water, with a suffix: original meaning something along the lines of “animal that lives in water”. Reconstructed Indo-European “udro”, reconstructed Proto-Germanic “otraz”, attested Anglo-Saxon “otor”.

(Apologies if this is too far off the tetrapod zoology topic.)
#22 Zach Miller
March 12, 2007

I’m always wondering about salamanders and newts. Did reptiles branch off from that lineage, and that’s the reason they have similar body plans, or did salamanders and newts develop that body plan independantly of early reptiles?
#23 David Marjanovi?
March 12, 2007

I’m always wondering about salamanders and newts. Did reptiles branch off from that lineage, and that’s the reason they have similar body plans, or did salamanders and newts develop that body plan independantly of early reptiles?

Neither nor — that’s just the normal unmodified tetrapod shape.

plus there’s the issue of the feminine -ix suffix in the Latin form)

Well, the word is feminine in German, too. But gender inherits well.

The ENGLISH word “otter” (for a mustelid mammal) is unconnected: it is from the Indo-European wed- , which also gives us wet and water, with a suffix: original meaning something along the lines of “animal that lives in water”. Reconstructed Indo-European “udro”, reconstructed Proto-Germanic “otraz”, attested Anglo-Saxon “otor”.

We have that one in German, too! It differs from the snakes in being masculine.
#24 Sordes
March 15, 2007

It seems that this year�s herpeto-seasons has began. At monday I discovered the first newts in the garden-pond (Triturus alpestris) and saw several larvae of Salamandra salamandra in a small spring, two female specimens of Lacerata agilis and yesterday a Podarcis muralis.
#25 Darren Naish
March 15, 2007

Sordes (and others): note that European newt taxonomy has recently been revised. Triturus is now reserved only for the marbled newts and the ‘cristatus group’. The small European newts are Lissotriton, while the intermediate Alpine newt is Mesotriton. An excellent website, citing and discussing all of the relevant literature, can be found here. I was going to include all this in the article but decided to cut it for the usual reasons of length and time.
#26 Sordes
March 15, 2007

Thank you Darren.
It is also always again nice to watch the newts and feed them with worms. Their mating behavior is also really interesting, and in our pond the males are nearly always “flirting” with the females. Although they are only very small in size, I have also sometimes to think about the very first aquatic tetrapods, and that modern newts have during their aquatic season nearly the identical way of life. There are so many discussions about the origins of the tetrapod-limbs, and for what they were actually used. If you look how newts walk on the ground of the pond or are climbing in plants, you get a very good idea what could be their origin (and it looks also very similar to anglerfish and even salamander sharks).
#27 st
March 20, 2007

Darren: by your definition (“any member of the amphibian clade Salamandridae that is aquatic during the breeding season”): are American mole salamanders (Ambystoma) like our local, sometimes neotenic tiger salamanders “newts”?
#28 Darren Naish
March 20, 2007

Steve: thanks for the comment (and the others). So far as I know, ‘newt’ is only attached to Salamandridae. Mole salamanders are Ambystomatidae.

Since writing this post I’ve been out newt-watching several times. Have seen lots of local Palmate newts and an Alpine newt in captivity. Plus GCNs were in the local news recently as their discovery at a site might halt development plans there. We need to confirm whether GCNs really are at the site, which means another excuse for a newt-searching field excursion… stay tuned.
#29 Sordes
March 27, 2007

Today I saw the first Lissotriton vulgaris in the pond. To see five different species of reptiles and amphibians within such a short time is really rare here. Yesterday I saw also again many lizards (Lacerta agilis), and I was able to observe two of them from a distance of only about 10cm.
#30 narainne
November 6, 2007

walang kwenta!!!!!!!!!!!