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The more you know about colubrid snakes, the better a person you are

The views expressed are those of the author and are not necessarily those of Scientific American.


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A Smyth's water snake (Grayia smythii), photographed in the Congo. Image courtesy Kate Jackson.

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I really like finding out about, and writing about, obscure tetrapods. And that’s not a difficult thing to do, since there are some pretty big, pretty diverse tetrapod groups out there that contain huge numbers of poorly known, little-mentioned species. I’ve come back to obscure snakes on a few occasions, and here’s another article where I aim to bring your attention to but a small number of snakes that you might not have heard about before. Of course, whether a species is ‘obscure’ depends on your point of view, and some of the species I’m discussing here are actually familiar animals to those who know their snakes. All of the snakes we’re looking at here are members of the gigantic group traditionally known as Colubridae. See below for the small-print on the use of this name.

The photos were taken by Bangor University’s Wolfgang Wüster and Whitman College’s Kate Jackson (unless stated otherwise) and are used with their kind permission. I’d also like to note that – when I want to know basic stuff about a snake I don’t know much about – my first ports-of-all are still Chris Mattison’s The Encyclopedia of Snakes and Harry Greene’s wonderful Snakes: the Evolution of Mystery in Nature.

Photo courtesy W. Wüster.

So, this is Ahaetulla prasina, photographed in Thailand. It’s one of eight or so Ahaetulla species, often known as Asian vine snakes, tree snakes or, unfortunately, as whip snakes*. They’re found throughout India, south-east Asia and on various Pacific islands. They’re colubrine colubrids, found in some phylogenies to be the sister-taxon to the rest of Colubrinae (Lawson et al. 2005). This is a surprisingly ‘basal’ position for such a strongly modified snake: the outgroups to Colubrinae are mostly terrestrial, short-skulled generalists. Pyron et al. (2011) also found this ‘basal’ position for Ahaetulla, but found evidence that it belongs in a little clade that also includes the Australo-Asian bronze-backed snakes or bronze-backs (Dendrelaphis) and the Asian flying snakes (Chrysopelea) [photo of C. ornata below by LA Dawson, from wikipedia].

* I say “unfortunately” because the name ‘whip snake’ is used for diverse, distantly related slender-bodied snakes from all around the world.

Chrysopelea ornata, photo by LA Dawson.

It seems, then, that this specialised clade of highly arboreal, very slender-bodied, mostly skink-eating colubrines diverged early on in colubrine history from a generalised, robust-bodied, predominantly terrestrial colubrine ancestor. To those primarily interested in ecology and behaviour and who don’t see the point of all this obsessing with phylogenetics, I care about this stuff because it allows us to hypothesise about ancestral states and about the changes lineages undergo across time. Basically, it provides the historical skeleton that we need if we want to make inferences about patterns in evolution. Asian vine snakes and flying snakes are specialised predators of arboreal lizards, and bronzebacks mostly eat lizards as well. If these three colubrine lineages do form a clade, was their emergence and subsequent diversification driven by the skink radiation? Questions like this can only be examined when you have phylogenies to work with (and time-calibrated phylogenies at that).

Ornate water snake (Grayia ornata), photo by Kate Jackson.

Lawson et al. (2005) found the four African water snakes (Grayia) to be the sister-taxon to the Ahaetulla + other Colubrinae clade. As suggested by the common name, African water snakes are semi-aquatic and eat fish, frogs and tadpoles. They’re robust and large, reaching 1.7 m and even 2.5 m in a few places in western Africa (Spawls et al. 2004). Grayia has always been difficult to place phylogenetically. Some authors have allied it with natricines or xenodontines, or have suggested that it might be outside a natricine + calamariine + colubrine clade (Kelly et al. 2003). Hemipenis morphology in snakes provides a great deal of phylogenetically important information and the hemipenis of Grayia differs quite strongly from that of colubrines – the organ is symmetrical and has a forked sulcus spermaticus in Grayia, whereas it’s asymmetrical in colubrines. Kelly et al. (2003) gave Grayia its own ‘subfamily’ (Grayiinae) in order to emphasise its distinction relative to Colubrinae (in phylogenetic terms, such acts are redundant, since Grayia already stands as a distinct lineage).

Juvenile Smyth's water snake (Grayia smythii). Photo courtesy K. Jackson.

Anyway, I digress. I think that most people will find the name Ahaetulla unfamiliar, but not necessarily the snake itself – Asian vine snakes were often known by the junior synonym Dryophis until quite recently (the former name is Ahaetulla Link, 1807; the latter is Dryophis Dalman, 1823). These are very slender bodied snakes with long, pointed snouts and enlarged fangs at the front of the lower jaws (a possible adaptation for grabbing smooth-scaled lizard prey). Their most peculiar and remarkable feature is of course their horizontal pupils, shaped in some species like a horizontally rotated keyhole (that is, with a circular portion posteriorly, and a tapering, bar-shaped portion anteriorly). They’re rear-fanged, and are further unusual in being viviparous. Elsewhere in Colubrinae, viviparity is – I think – only present in smooth snakes (Coronella) and mock vipers (Psammodynastes). Most Asian vine snakes (including A. prasina) eat lizards, occasionally small mammals, but A. fronticincta reaches down from branches over water to grab fish.

Photo courtesy W. Wüster.

Convergent evolution is a fascinating phenomenon, and here [above] is the South American colubrid Oxybelis fulgidus (this one was photographed in Brazil), well known for being highly similar morphologically to Ahaetulla. The two are not close phylogenetically. While Ahaetulla is seemingly outside the enormous clade that includes the vast majority of colubrine taxa, molecular studies find Oxybelis to be deeply nested within a tropical American colubrine clade that includes cribos (Drymarchon), coachwhips (Masticophis) and tiger snakes (Spilotes), and to be the sister-taxon to the arthropod-eating green snakes (Opheodrys) (Lawson et al. 2005, Pyron et al. 2011). Most of these colubrines are generalised, predominantly terrestrial predators of small vertebrates, but some (like Spilotes) are also narrow-bodied, long-headed arboreal specialists.

The four Oxybelis species are often known as vine snakes – they occur from Arizona in the north to Peru in the south and, like Ahaetulla, possess the really slender bodies and long, pointed snouts typical of highly arboreal snakes. Again, they’re back-fanged diurnal predators, mostly of lizards, but (unlike Ahaetulla) their large eyes have round pupils.

Philodryas olfersii, photographed in Brazil, courtesy Wolfgang Wüster.

Other colubrids are convergently similar to Ahaetulla and Oxybelis as well. Madagascar is home to the leaf-nosed snakes (Langaha), also sometimes called vine snakes (sigh, people are so unoriginal when it comes to common names) and best known for their crazy, sexually dimorphic nose-leaves (note that this structure isn’t unique to L. madagascariensis as you might think from most books). Langaha is not close to colubrines of any sort, instead being part of the pseudoxyrhophiine clade. Then there’s Xenoxybelis, a dipsadine [read on] probably close to (or part of) Philodryas. One of the Philodryas species is shown here.

Photo courtesy W. Wüster.

Here’s a Black-striped snake Coniophanes imperialis, a rear-fanged, oviparous colubrid, one of 12 Coniophanes species. They occur from Texas in the north to Peru in the south. All Coniophanes snakes have longitudinal stripes on their bodies and smooth, shiny scales. Coniophanes is part of Dipsadinae, a major colubrid clade that doesn’t really include any well known species, though the North American hognose snakes (Heterodon) are part of this clade if it’s understood to include the xenodontines. Indeed, there’s a reasonable amount of confusion as to whether Dipsadinae is synonymous with Xenodontinae (Dipsadidae Bonaparte, 1838 has priority over Xenodontinae Bonaparte, 1845), whether the two are related – but distinct – clades, or whether Xenodontinae is a clade within a more inclusive group that can be termed either Dipsadidae or Dipsadinae. I think the last of those options is most likely.

Leptodeira annulata, photo courtesy Wolfgang-Wuster.

American cat-eyed snakes (Leptodeira) and the blunt-headed tree-snakes or blunt-headed vine-snakes (Imantodes), famous for their bulging eyes and exceptionally slender neck regions, are almost certainly dipsadines too. Night snakes (Hypsiglena) and their relatives are also dipadines (see this Tet Zoo ver 2 article), as are the goo-eaters. Yup, I said goo-eaters. Really must write about them at some stage…

Pyron et al. (2011) found Coniophanes to be part of a dipsadine clade that also included the terrestrial, sometimes semi-fossorial graceful brown snakes (Rhadinaea) and the Central American rainforest snake Amastridium veliferum. The Coniophanes species shown above (the Black-striped snake) is most often found under piles of leaves and other debris and preys on lizards and nestling rodents. It seems to be highly adaptable and ecologically flexible, occurring in dry savannahs and farmland in the north to moist forest and even marshy areas further south. It seems to be tolerant of human disturbance and this, combined with its flexibility, means that it is presently of little conservation concern and seemingly remains in healthy numbers throughout its range.

The whole colubrid mess, again

I mentioned at the top that “small print” has to be used whenever the term ‘Colubridae’ is discussed. This is because there are differing views as how this name should be used. Colubridae as traditionally conceived is an enormous group containing nearly 2000 snake species, and such is its diversity that numerous separate ‘subfamilies’ have been named for clusters of species. The discovery that these ‘subfamilies’ are not really closely related (some seem to be outside the clade that includes viperids, elapids and other ‘colubrids’ while others are closer to elapids than to other ‘colubrids’) means that some authors now use a taxonomic system where just about all traditional ‘subfamilies’ are elevated to ‘family’ level (Vidal et al. 2007, Zaher et al. 2009). The taxonomy and phylogeny favoured by these authors is depicted in the adjacent diagram.

I personally prefer this system. I think it better reflects diversity and disparity to have the clades identified as ‘families’, and I think that biologists and other people tend to understate and underestimate extant lizard and snake diversity and disparity because, for reasons of social inertia, these animals have (unlike birds and mammals) historically been grouped into a low number of ‘families’. Amphibians are affected by the same problem.

Summary phylogeny for colubroids, based on maximum likelihood analysis of five genes, from Pyron et al. (2011).

However, not everybody agrees with this approach. Pyron et al. (2011) simply stated that changing the status of these clades is unnecessary. But the fact that a large number of ‘colubrid’ ‘subfamilies’ grouped closer to elapids than to colubrines meant that they opted to united the respective groups within an inclusive, ‘family’-level clade termed Lamprophiidae. Colubridae, in their system, was therefore limited to the clade that included natricines, pseudoxenodontines, dipsadines, scaphiodontiphiines, calamariines, grayiines and colubrines (see adjacent phylogeny, from Pyron et al. (2011)). We’re looked at this area (that is, the content and membership of Colubridae sensu lato) a few times before on Tet Zoo (see links below): sloooowly but surely, I aim to say at least something about all of these complex, diverse snake clades.

Lest we forget…

Lest we forget, colubrines and all other kinds of snakes are threatened worldwide by habitat degradation and loss. Species in Madagascar, the American tropics and south-east Asia in particular are potentially in great danger as forests, scrublands and deserts are reduced in size or damaged ecologically as a result of climate change, drought, or the loss of neighbour species in their ecosystems.

In tropical Asia, major and mostly unregulated harvesting of wild snakes for their meat, gall bladders and skin is definitely having an impact on the populations of some species. In Vietnam, local people earn three to five times as much income from trading in snakes than they do from cultivating crops and selling vegetables (more on that here; free pdf here), so it’s not surprising that a massive and unsustainable trade in snakes is underway. Indeed, CITES recently described the Asian snake trade as “one of the largest under-regulated trades in terrestrial wildlife globally”. It’s difficult to know what can be done about the Asian market in snakes – I doubt that many readers of this blog are in the regular habit of consuming snake meat (especially that from unsustainably harvested, wild-caught snakes), and it seems that the vast percentage of the consumer base have no interest in, or concern about, animal welfare, conservation or sustainability.

Ok, my initial plan was to get through a much higher number of taxa. Alas.

Thanks again to Wolfgang Wüster and Kate Jackson for use of the images.

For previous Tet Zoo articles on snakes (some of which are very obscure, some of which are not), see…

Refs – -

Lawson, R., Slowinski, J., Crother, B., & Burbrink, F. (2005). Phylogeny of the Colubroidea (Serpentes): New evidence from mitochondrial and nuclear genes Molecular Phylogenetics and Evolution, 37 (2), 581-601 DOI: 10.1016/j.ympev.2005.07.016

Kelly, C. M. R., Barker, N, P. & Villet, M. H. 2003. Phylogenetics of advanced snakes (Caenophidia) based on four mitochondrial genes. Systematic Biology 52, 439-459.

Pyron, R. A., Burbrink, F. T., Colli, G. R., Montes de Oca, A. N., Vitt, L. J., Kuczynski, C. A. & Wiens, J. J. 2011. The phylogeny of advanced snakes (Colubroidea), with discovery of a new subfamily and comparison of support methods for likelihood trees. Molecular Phylogenetics and Evolution 58, 329-342.

Spawls, S., Howell, K., Drewes, R. & Ashe, J. 2004. A Field Guide to the Reptiles of East Africa. A & C Black (London).

Vidal, N., Delmas, A.-S., David, P. Cruaud, C., Couloux, A. & Hedges, S. B. 2007. The phylogeny and classification of caenophidian snakes inferred from seven nuclear protein-coding genes. C. R. Biologies 330, 182-187.

Zaher, H., Grazziotin, F. G., Cadle, J. E., Murphy, R. W., Cesar de Moura-Leite, J. & Bonatto, S. L. 2009. Molecular phylogeny of advanced snakes (Serpentes, Caenophidia) with an emphasis on South American xenodontines: a revised classification and descriptions of new taxa. Papéis Avulsos de Zoologia, Museu de Zoologia da Universidade de São Paulo 49, 115-153.

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. John Harshman 4:32 pm 01/30/2012

    Cool snakes. I’m glad to see I have made you embarrassed enough about the word “basal” that you feel required to put it in quotes. But why would it be surprising to find a “basal” clade to be highly derived in morphology? See how pernicious “basal” can be? Leads to bad assumptions about evolution.

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  2. 2. naishd 4:39 pm 01/30/2012

    As usual :) you’re right – the reason I was regarding the ‘basal’ position to be surprising is that all the snakes around this clade in the phylogeny are robust-bodied, short-headed, mostly terrestrial generalists, not half-decent or decent climbers that might look like better potential antecedents to the highly specialised arboreal colubrines in question.

    Darren

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  3. 3. John Harshman 7:20 pm 01/30/2012

    What potential antecedents would be featured on a tree of extant species? See? “Basal” is evil. One naturally expects “basal” groups to be “primitive”. But since there’s no such thing as a “basal” group, we should have no such expectations.

    The only reason to be surprised about a particular clade developing some particular feature is if you think some other feature, one they don’t have, ought to be a prerequisite. Or we might be slightly surprised to find coordinated homoplasy in several characters.

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  4. 4. Therizinosaurus 8:09 pm 01/30/2012

    Very interesting to see the cladistic consensus that has emerged since my childhood nature book days of all ‘advanced’ snakes being colubrids, viperids or elapids. I’d probably agree with Pyron et al.’s approach to leave taxonomy alone as much as possible given the new topology. Seems similar to Benson et al. wanting to create Neovenatoridae for Neovenator and megaraptorians, when they all fall within the existing definition of Carcharodontosauridae. By saying Neovenatoridae or Natricidae deserve to be families, you’re saying there’s something special or quantifiable about ranks.

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  5. 5. Heteromeles 12:54 am 01/31/2012

    Thanks for the great post. I’ve got to admit, Greene section on colubrids was a bit confusing for me, and this helps.

    As for conservation, this gets a bit tricky. Getting friendly with Chinese herpetologists (and Vietnamese herpetologists) is one good thing, supporting Chinese grad students and post docs is another. The major positive impact these snakes have in people’s lives is probably in terms of trophic cascades, where the presence of snakes leads to fewer pests. Also, working with the rural poor on sustainable snake harvesting practices is a fairly normal development, as is getting rural cooperatives to control production of snakes in a sustainable way while increasing product quality.

    The other fun thing is for the parasitologists, epidemiologists, and toxicologists to go to work on determining how safe snake wine and snake products are. Are snake venoms neutralized by alcohol, for example? What kinds of interesting parasites will eat your brain/heart/liver if you eat a snake without proper hygiene? How safe is a drink made from a living snake drowned in alcohol? How often are these things faked or adulterated? There might be room for a whole career in there.

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  6. 6. naishd 4:30 am 01/31/2012

    Thanks for comments. On the term ‘basal’, I have to admit that I haven’t yet met or corresponded with anyone who dislikes the term as much as you, John, and it’s still being used very widely in the literature – as we’ve said before, it’s just shorthand for ‘furthest from the youngest part of the tree’, and it doesn’t necessarily mean ‘primitive’. As for the position of that arboreal colubrine snake clade and ‘potential antecedents’, I think it seems reasonable to expect extant members of closely related lineages to give hints about the strong modification present in the arboreal clade. That is, I would predict that strongly arboreal clade to be nested within a larger, ‘mostly arboreal’ clade, not to be surrounded by mostly terrestrial generalists.

    Darren

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  7. 7. MikeTaylor 7:27 am 01/31/2012

    “On the term ‘basal’, I have to admit that I haven’t yet met or corresponded with anyone who dislikes the term as much as you, John.”
    Well, you can put me in second place. It’s not that it’s a bad term; it’s that it’s purely relative, but sounds scientific enough that people are fooled into thinking it means something subjective.
    “As we’ve said before, it’s just shorthand for ‘furthest from the youngest part of the tree’.”
    What do you mean by the “youngest” part of the tree? When you’re dealing with extant groups, as here, all relevant branches are equally young. Ahaetulla diverged from its sister taxon containing the other colubrids at exactly the same time that its sister taxon diverged from it. Neither one is more basal than the other. What we usually mean by “basal” in this situation is “the half of the node that I’m not going to go on and talk about”. Sometimes it means “the half of the node that is less speciose”.
    (The only time “basal” means anything objective is when you are considering a sequence of divergences from a specific perspective. So if you’re thinking about Titanosaurs, then Diplodocids are more basal than Brachiosaurs because they diverged earlier. But if you’re thinking about Dicraeosaurids, then Brachiosaurs are more basal than Diplodocids for the same reason.)
    So: “basal” is usually unhelpful, and it’s generally better to talk about either “old” (for a clade that originated long ago) or “primitive” (for a clade that is morphologically conservative). (I know that “primitive” is unfashionable, but that’s neither here not there. It’s more scientific than “basal” because it has a specific meaning.)

    Also: Dear SciAm, where the HECK is the “notify my of followups” checkbox? Come on. You’ve been doing this for a long time now. You have got to sort out your sorry excuse for a blogging platform. SRSLY.

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  8. 8. MikeTaylor 7:28 am 01/31/2012

    Side-rant: Since my comments usually appear with double spacing between paragraphs, I left out the blank lines this time. The result: no paragraph breaks. So it looks like there is NO WAY to get a single line of whitespace between paragraphs — even though that it always what you want. Someone please tell me that this isn’t true, that I am missing something.

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  9. 9. Maija Karala 8:10 am 01/31/2012

    Interesting, especially the part about Ahaetulla. It shouldn’t be surprising, of course, that ‘basal’ clades can be highly specialized, since they have had exactly as much time to evolve as the derived ones. The word still leaves one to expect morphologically primitive creatures.

    The keyhole-shaped pupils of Ahaetulla are truly weird. I met A. nasuta (I suppose) in Sri Lanka, and was particularly struck by them. I wonder what benefit the pupils give, if any.

    Here’s the individual I saw. It was less than 1 m long, which apparently means it’s not yet fully grown.
    http://planeetanihmeet.files.wordpress.com/2011/02/p1090577.jpg

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  10. 10. Dartian 8:35 am 01/31/2012

    Mike:
    it’s generally better to talk about [...] “primitive” (for a clade that is morphologically conservative)

    Yes – as long as you keep in mind that ‘primitive’ doesn’t automatically need to mean morphologically primitive; there are other ways (e.g., behavioural) in which organisms can be primitive compared to their relatives.

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  11. 11. Hai~Ren 12:33 pm 01/31/2012

    You can never have too many posts about snakes!

    Ahaetulla, Dendrelaphis and Chrysopelea snakes are familiar to many of us in Singapore, as these arboreal snakes can be common even in suburban parks and gardens, wherever there are sufficient trees and shrubs. I’m not sure if they’re supposed to be skink specialists though; arboreal skinks aren’t very common here, and most sightings of these snakes attacking prey have involved geckos and agamids.

    I find it very interesting that while Ahaetulla and Chrysopelea are considered to be rear-fanged and mildly venomous, Dendrelaphis has always been thought to be nonvenomous. Now that we know that venoms are actually more widespread amongst ‘colubrids’, I wonder if we just haven’t looked hard enough for venom in bronzebacks, or if they have indeed lost the ability to produce venom. I also wonder where the cat snakes (Boiga) fit in as well, since they are another group of highly arboreal, slender-bodied Southeast Asian snakes often slotted into the Colubrinae.

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  12. 12. naishd 1:10 pm 01/31/2012

    Thanks loads for additional comments. On the nefarious term ‘basal’, I should note that I try to avoid using it in publications for the reasons given above. While I certainly agree that it’s a loaded term, with various ‘negative’ connotations, I think it’s generally assumed that it’s relative; it’s generally obvious that it means “furthest away from the taxa that evolved most recently within the clade I’m interested in”. So, in the first of the two snake cladograms used above, most people would imagine Boidae to be ‘basal’ relative to colubrids and such. Not difficult to understand.

    Given the connotations about the term, I do agree that we should stop using it. I’ll do so if everyone else does :)

    Darren

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  13. 13. naishd 1:24 pm 01/31/2012

    Hai-Ren (comment 11): specialisation on a diet of skinks is one of those things that people say in the literature (for flying snakes etc.), and I suppose it may only be true across parts of the animal’s ranges. Or maybe Singapore is unusual?

    Boiga is uncontroversially a colubrine, not that far away from such classic colubrines as kingsnakes, gopher snakes, rat snakes etc. Molecular phylogenies have found it to be especially close to egg-eaters (Dasypeltis) (the two are sometimes recovered as sister-groups) and wolfsnakes (Dinodon and Lycodon).

    Darren

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  14. 14. farandfew 5:44 am 02/1/2012

    Darren, I’m ashamed to say that I have not come across the work you reference on Vietnamese snake-catchers but could you check the links? One seems to be an article about Indonesia, the one to the pdf takes me to a Sci Am error page.

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  15. 15. naishd 5:50 am 02/1/2012

    Thanks for pointing this out. The first link is correct and leads to the article ‘Rat snakes on a slippery slope’, but the second link was broken and has now been fixed. It leads directly to a pdf of Mark Auliya’s report ‘Conservation status and impact of trade on the Oriental rat snake Ptyas mucosa in Java, Indonesia’.

    Darren

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  16. 16. naishd 5:59 am 02/1/2012

    Sorry, maybe you meant that you were looking for links to the stuff about Vietnam. The third link – the one to the CITES report – does reference some of the Vietnamese stuff. It’s easy to find more online (google ‘Vietnam snake trade’ or such): this issue of Traffic Bulletin also includes an article on snake trade in Vietnam. Basically, people seem to be catching and selling all snakes they see, of all kinds, either for the pet trade or (mostly) to eat. Snakes are on sale by the hundred at trade stores, with those who catch them saying that they’re becoming harder to find. I wonder why (sarcasm).

    Darren

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  17. 17. naishd 6:14 am 02/1/2012

    One more thing… one of the most interesting recent field discoveries about the Asian snake trade (by ‘interesting’ I mean ‘dreadful’) is that people indiscriminately harvest all snakes, of all kinds, all sizes, all ages. Everything, from pythons to sunbeam snakes, tentacled snakes, watersnakes, cobras, kraits and so on. Most discussion has focused on the exploitation of ratsnakes, but there’s evidently a bigger problem. Turtles are also strongly affected by the restaurant trade – many Asian species are now critically endangered, locally extinct, or wholly extinct.

    Darren

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  18. 18. Hai~Ren 10:00 am 02/1/2012

    Indeed, there is a lot of exploitation of snakes, turtles and lizards in Southeast Asia – some of these go to the exotic pet trade, others end up in the market for meat or medicinal products. If I’m not wrong, a lot of this ends up in China.

    There are a number of ‘farms’ in Thailand, Vietnam, and Cambodia, which supposedly ranch pythons for leather and for export as pets, or house venomous snakes that are milked for their venom, but based on what I’ve been seeing online, many of these ‘farms’ seem to exist more as roadside zoos, where the main attraction usually involves a twisted version of snake charming, in which some local shows off his agility and skill in the arena, dodging the strikes of an angry cobra. And I believe that many of these ‘farms’ are part of the laundering process, with wild-caught snakes arriving at these ‘farms’ before being shipped out and labelled as being captive-bred.

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  19. 19. Heteromeles 11:00 am 02/1/2012

    Perhaps we can start a Florida python meat industry and undercut that part of the south Asian trade?

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  20. 20. Jerzy New 4:25 am 02/2/2012

    Actually, eating snakes may have serious risk of chemical poisoning. Snakes are predators or predators, and SE Asia has how appaling pollution, and snakes might well concentrate poisons inside them.

    From talking with a friend who lives in Vietnam, problem there is eating of every kind of wild animals, not only snakes. Apparently, this is now more a fashion or semi-luxury than lack of other sources of proteins.

    Which opens a way to education/media campaign trying to change fashion/placement of anti-wildlife-eating scenes in popular TV shows etc.

    There are even stories circulating about illegal tiger farms breeding tigers for exclusive banquets, at a cost of thousands of bucks. Apparently customers are often corrupt officials or crime bosses.

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  21. 21. naishd 4:50 am 02/2/2012

    Yeah, I bet snakes carry lots of horrible parasites as well. Asia does seem to be creating a lot of wildlife problems due to sheer culinary demand: shark fins, tiger bone, pangolins, turtles, frogs…

    Darren

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  22. 22. David Marjanović 10:13 am 02/2/2012

    Perhaps we can start a Florida python meat industry and undercut that part of the south Asian trade?

    Sounds good to me.

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  23. 23. paalexan 3:27 pm 02/4/2012

    Regarding “basal”– the problem with getting rid of this term is that you’d just have to come up with a synonym! It’s just too useful. We repeatedly infer phylogenies like this: ((((A)B)C)D), where A is a huge, diverse clade with lots of apomorphic characters while B, C, and D are depauperate clades with lots of plesiomorphic characters. That pattern isn’t going to go away if we reject the term “basal”, and we’re still going to need to talk about it.

    Another point:

    “I personally prefer this system. I think it better reflects diversity and disparity to have the clades identified as ‘families’, and I think that biologists and other people tend to understate and underestimate extant lizard and snake diversity and disparity because, for reasons of social inertia, these animals have (unlike birds and mammals) historically been grouped into a low number of ‘families’. Amphibians are affected by the same problem.”

    I think this is backwards. Viewed in the context of biological taxonomy as a whole, squamate families are not unusually large; instead, bird & mammal families are unusually small. If we want “family” to mean something consistent across major lineages, it would be much, much simpler to modify taxonomy of birds & mammals – which are, in the grand scheme, rather small groups – than to reorganize the taxonomy of the other 99+% of the world’s biodiversity. However, to normalize the meaning of ranks like “family” we would also need some sort of coherent, objective standard (e.g., age of origin of the clade) that is generally applicable. This idea has been floating around for quite a while but has never gained much traction. Absent such a standard, the idea that families in a particular higher taxon are “too large” or “too small” are just subjective pronouncements devoid of empirical or theoretical content.

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  24. 24. farandfew 5:44 am 02/8/2012

    Sorry for not checking back there, Darren and all. Actually what I was looking for was a reference to the statement that people make more from hunting and selling snakes than from agriculture in Vietnam. It’s not at all a surprising statement but I was hoping for some figures on it. I can’t find anything about Vietnam in the documents you link too though and it’s suspiciously absent from the countries presenting at the CITES Asian Trade workshop which you mention in your more recent post.

    Jerzy’s assessment of the situation in Vietnam is essentially correct although some animals, including snakes, are more valuable than others and some snakes are more valuable than other snakes – King Cobras and pythons for instance.
    But the idea that a media and education campaign can solve the problem is one that needs a critical examination. Before I went to Vietnam, I thought that wildlife eating might be compared to a phenomenon like egg-collecting in the UK, something practiced by a handful of obsessives which public opinion rapidly turned against. As I understand it after five years in the country and reading a lot of literature (I would recommend Rebecca Drury’s work particularly) it would be better to compare it to organic farming.
    If, for the sake of argument, you proved that organic farming was bad for biodiversity, imagine the difficulty you’d have convincing people in Europe to give up organic food and you’d get some way towards imagining how difficult it is to save Asian wildlife through a media campaign. Some way, but not all the way; you also have to factor in the fact that nobody likes foreigners telling them what to do, particularly people who already have had to put up with rather a lot of that from westerners in the last century. And that there are almost certainly people making money off the wildlife trade who are able to influence the far more powerful state media organs to send opposite messages. My impression is that – to paraphrase Patrick Moore on a comet hitting Jupiter- you might as well try to stop a charging rhinoceros by throwing a baked bean at it.
    On the other hand I think Heteromeles’ idea about a Florida python market is truly an excellent one. Seriously. Much traded wildlife goes to Asian communities in the US anyway.

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  25. 25. farandfew 6:00 am 02/8/2012

    Also, I want to say that, when people in Vietnam say that wildlife is getting harder to find, in my experience they typically have no illusions whatever about the reason. But they are stuck in a classic Tragedy of the Commons. If they don’t kill the animal themselves, all that will happen is that somebody else will kill it; they have no way to stop them doing so. It’s not a choice between money and wild animals, it’s a choice between money and no wild animals vs no money and no wild animals.

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  26. 26. Christopher Taylor 9:10 pm 02/9/2012

    My impression is that – to paraphrase Patrick Moore on a comet hitting Jupiter

    Witness the power of punctuation. I have to admit that this bit had me very confused for a moment because, instead of reading it as ‘Patrick Moore, on a comet hitting Jupiter’, I read it as ‘Patrick Moore, on a comet, hitting Jupiter’.

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  27. 27. CS Shelton 11:55 pm 02/9/2012

    “To those … who don’t see the point of all this obsessing with phylogenetics, I care about this stuff because it allows us to hypothesise about ancestral states…”

    …And that is my raison d’etre. One o’ these days, if I get the time (maybe when I’m retired, if that’s possible in three decades), I’m gonna compile the info and start constructing missing links from this data. I want to reconstruct animals that must have existed for which we have no fossils.

    Now I duck while scientific purists give me the business. *ouch*

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  28. 28. llewelly 6:39 pm 02/11/2012

    “I want to reconstruct animals that must have existed for which we have no fossils.”

    Haven’t linguists already done the equivalent of this for languages? For example, the ancestral Indo-European and Bantu languages.

    FWIW, popular writings about paleontology and evolution are filled to overflowing with speculation (science driven, but speculation nonetheless) about the appearance, ecological role, behavior, etc, of the ancestors of many modern groups of animals. Many of the paleontologists (Peter Ward, Donald Prothero, Jack Horner, and plenty of others) writing such material openly state, that while such speculations are strongly based on fossils, in either most or all cases, the fossils in question are at best fossils of near relatives to the ancestors, rather than being actual ancestors themselves.

    Now perhaps you’re thinking of ancestral animals for which there are no near-relative fossils. Even so, seems like a natural, if much more difficult, and necessarily lower confidence, extension of what scientists are already doing.

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  29. 29. David Marjanović 11:05 am 02/13/2012

    I like the terms “crownward” and “rootward”. However, this only works in clades that consist of a crown and a stem.

    Otherwise, I often replace “basalmost” by “the sister-group to all others” in my own writing.

    Now I duck while scientific purists give me the business.

    Why?

    Haven’t linguists already done the equivalent of this for languages? For example, the ancestral Indo-European and Bantu languages.

    Oh yes. In fact, they consider it a necessary part of phylogenetics. If you can’t reconstruct the MRCA of the clade you propose, they’ll commonly harp like creationists about how your “theory” is “unproven”; and of course if you can’t reconstruct such an ancestor without contradicting yourself somewhere, your hypothesis is in trouble.

    For characters in a data matrix, ancestral-state reconstruction is easy: just read the states off a cladogram. Plot the states on the cladogram and trace them back to whichever node you like. MacClade, Mesquite, and to some degree even PAUP* will do that for you.

    Link to this
  30. 30. David Marjanović 11:06 am 02/13/2012

    Actually, the reconstruction of ancestors at every node is part of the way PAUP* builds trees in the first place.

    Link to this

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