Weekly Spotlight: Wonambi

28 01 2010

Good tidings and well-wishes!

(NOTE: I’ve decided to replace the word ‘Wonders’ with ‘Spotlight’ for this series because it’s more…well…’theatrical’.)

To the comparative anatomist, few creatures possess the intrigue of snakes. The underlying rationale of this contention is simple: whether we’re observing a 300-pound python or a robust adder, snakes invariably put our perception of how animals move to the most rigorous of tests. Those who equate speed with ‘leg size’ are utterly perplexed by the nimble mamba while those who believe that raw power is bound to the strength of limbs and jaws are stunned by the sheer might of a common boa. For these reasons among a hoard of others, snakes have developed into an incomparably divisive cultural icon: one would be truly hard-pressed to locate any sort of mythological reference to these beasts which could even come close to being cited as ‘neutral’. Despite (or perhaps ‘due to’) this phenomenon, snakes have always reaped an enormous amount of attention from any race of people fortunate enough to live alongside them.

What most people don’t realize, however, is that these fascinating animals are of intense interest to evolutionary biologists and paleontologists as well, for their fossil record reverses another unscientific assumption which has become ingrained into our collective psyche: the idea that the presence of limbs are a sign that one has ‘climbed the evolutionary tree’ (so to speak) to a higher vantage point than one’s legless cousins. The fact that serpents have lost their limbs utterly astounds most laymen along with the contention that, as a whole, lizards are the more primitive group. The question of why they opted to reverse the several-hundred-million-year-old trend of developing legs is one which contains such an enormous degree of controversy as to prohibit its discussion in this humble venue. I shall therefore leave my audience with one final note on the matter: the scientific community is, as a whole, unsure whether snakes lost their limbs to better facilitate burrowing or marine life (which would have, ideally, resulted in their eventual return to the terrestrial haunts of their ancestors…for the record, I belong to the former school of thought).

This mystery isn’t assisted by the fossil record to a degree even remotely approached by that with which it has aided our efforts to solve the riddles of avain and cetacean evolution because snakes generally possess comparatively delicate skeletons. Nonetheless, the efforts of fossil hunters have yielded a number of intriguing prehistoric serpents such as the appreciably large Australian genus Wonambi.

Wonambi skull reconstructions, the larger of which belong to W. naracoortensis while their smaller companions belong to W. barriei.

Wonambi is by a wide margin the best-known member of the extinct Madtsoiidae family whose chronological reign extended from the late Cretaceous to the late Pleistocene and whose members have been unearthed in South America, Africa, India, Southern Europe, and (most famously) Australia. For a full list of the group’s distinguishing characteristics, I’d recommend consulting the link provided earlier in this paragraph, though I’ll highlight a few below:

-Generally long and cylindrical bodies.

-Long and narrow skulls with tightly-fixed upper jaws.

-Rounded snouts.

-A braincase which is fairly narrow when viewed from between the orbits (‘eye sockets’) but which widens posteriorly.

-Elongate vertebrae which become lower more posteriorly.

-No sign of limb elements (unlike several other species).

An illustrated selection of Wonambi vertebrae.

In “Stalking The Plumed Serpent And Other Adventures In Herpetology”, D. Bruce Mans writes:

“No Madtsoiid snakes survive anywhere today, but fossils of Wonambi naracoortensis indicate that this species was present in Australia until the late Pleistocene, only about 40,000 years ago, and maybe even more recently. Aboriginal man is known to have arrived in Australia at least 60,000 years ago, so it’s highly probable that man was in Australia at the same time as Wonambi naracoortensis. Was Wonambi the source of the rainbow serpent myth?

Wonambi is a local Aboriginal word meaning giant snake or rainbow serpent, which is why paleontologist Meredith Smith used that name when she described the snake in 1976. A chill goes up my spine as I stare down in my hand at a vertebra of Wonambi. This giant snake, estimated to be about 18 feet long [(5.5 meters)] and as thick as a telegraph pole [(more on that later)] was the last of a long line of snakes in a primitive snake family whose evolutionary history was longer than the rise and domination of Earth by modern mammals and flowering plants.”

A display in which a heavily reconstructed Wonambi battles for its life against the marsupial lion, Thylacoelo carnifex.

The last sentence of Mans’ statement likely raised a few eyebrows from my herpetologically-inclined readers, for to them it’s no secret that reptile sizes are often exaggerated (some early dispatches from South American explorers claim that Anacondas reach lengths of 18 meters, while the longest recorded specimen only stretched to half that size). However, the size estimates described above are in fact real, though this certainly isn’t to say that Wonambi was a true ‘giant among serpents’ as Ralph E. Molnar points out in “Dragons In The Dust: The Paleobiology Of The Giant Monitor Lizard Megalania” (which I’ve previously cited at length here):

“The squamates (snakes and lizards)… evolved large predators in Australia, including Megalania among lizards, as well as large snakes such as WonambiWonambi was not that large for a snake, not in the same class as Megalania among lizards. John Scanlon (…Australia’s only specialist in fossil snakes) responded to the remark that Wonambi had a head the size of a shovel with a letter to the magazine Nature Australia showing that the shovel must have been of the kind used by small children to build sand castles on the beach. Even so, Wonambi was big enough, at about 6 meters long, to give a healthy fright to anyone encountering it- if there was actually anyone around to encounter it before it became extinct.”

A large Wonambi stalks its marsupial prey.

Though there’s not much else to say about Wonambi scientifically, the idea that the massive snake may have given rise to the mythical rainbow serpent demands further discussion. According to Aboriginal Art Online:

“The belief in the Rainbow Snake, a personification of fertility, increase (richness in propoagation of plants and animals) and rain, is common throughout Australia. It is a creator of human beings, having life-giving powers that send conception spirits to all the waterholes. It is responsible for regenerating rains, and also for storms and floods when it acts as an agent of punishment against those who transgress the law or upset it in any way. It swallows people in great floods and regurgitates their bones, which turn into stone, thus documenting such events. Rainbow snakes can also enter a man and endow him with magical powers, or leave ‘little rainbows’, their progeny, within his body which will make him ail and die. As the regenerative and reproductive power in nature and human beings, it is the main character in the region’s major rituals.”

While this hypothesis, if true, certainly wouldn’t mark the only occasion in which extinct beasts have directly influenced mythology, the notion that Wonambi may have led to what is arguably the most God-like character of Aboriginal culture is truly captivating.

A massive Wonambi devours a moderately-large marsupial. (Hat tip to my regular reader Doug)

May the fossil record continue to enchant us all!

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10 responses

28 01 2010
New Theory of Primate Origins Sparks Controversy | AboutScienceNow.info

[…] Weekly Spotlight: Wonambi « The Theatrical Tanystropheus […]

29 01 2010
Doug

How do we know how big it was? Cause i have heard a lower estimate…

29 01 2010
tanystropheus

I assume the length estimates were made by comparing Wonambi remains to modern pythons due to their fairly similar anatomical makeup (though they’re unrelated to the extinct snake). However, I haven’t found an exact quote on the subject.

29 01 2010
Bruce Keegan

I thought that you were going to talk about the “Feathered Serpent”. Quetzalquatl. The origins of the MezoAmerican, benevolent god.

29 01 2010
tanystropheus

That’s certainly an intriguing mythological creature as well: and another example of popular culture treating snakes with reverence. Perhaps I SHOULD dedicate a post to Quetzalcoatl sometime…

30 01 2010
Doug

I asked because i have an article from the Summer 2003 isue of Nature Australia in which Stephen Wroe says he calculated the average size of Wonambi at “well under 13 kilograms”. Is that what an 18 foot snake weighs? I dunno. The article was very dogmatic, presenting everything as fact rather than speculation and he really comes of as having an axe to grind.

30 01 2010
tanystropheus

I believe that a modern Burmese python of that length would actually weigh around 181 kg, so this certainly isn’t a trivial difference of opinion in terms of Wonambi’s estimated weight.

2 02 2010
John Scanlon, FCD

Steve Wroe’s ‘average’ size estimates for reptiles assumed a juvenile-heavy population, which seems very unrealistic; juvenile mortality is high in most animals, so that if they may live for several decades as large reptiles can, a large majority of the individuals at any one time are in the adult size range. I’ve never seen any fossil remains of juvenile Wonambi naracoortensis, so there is actually no evidence at all for individuals weighing as little as 18 kg (nevertheless, they presumably did exist!). He was trying to debunk the idea that the large predator guild in Australia’s Pleistocene megafauna was dominated by reptiles rather than mammals. Hah! Wonambi, even with a head less than 10 cm across, could eat Thylacoleo for breakfast.

2 02 2010
Doug

John,
That’s why i said he came off as having an axe to grind. He also claims that Hetches estimates for Megalania were only for maximums (and ecological impact should be based on averages) but that Hetche left the necessary data for estimating averages. He claims that by using this data he calculated the average Megalania to be 12 feet long and about 220-240 pounds. I didn’t buy it because Megalania is known from very fragmentary remains, with the best specimen being a partial skeleton. I thought you needed a large sample size to calculate averages. He also cites the rarity of Megalania as being an indicator of it’s low ecological impact (i would exercise caution in determining the commonality of an aniaml based on fossils, because there’s biases that could affect the chances of fossilization). He stated that Quinkana shouldn’t be counted as a competitor with terrestrial predators because it wasn’t terrestrial (in the usual matter of fact manner he uses throughout the article). He says that four of the five features used to defend terrestriality in Quinkana appear in the dwarf caimon, which is still largely aquatic. I mean, the marsupial lion was one bad ass predator, but as far as i can tell the only other large mammalian predator was the Thylacine. While it was in a magazine rather than any serious journal, i think it goes without saying that it’s one of the worst science article I’ve ever read.

10 12 2010
Marcus

Late to the party.. I’ve wondered if _Wonambi_ was predominantly a semi-aquatic form, living like anacondas – the more cylindrical body may indicate a tendency towards swimming; this in turn could tie into the mythology, as the first human arrivals to Australia would encounter this sinuous, large, potentially hazardous animal living in waterways; it doesn’t take a big leap to get from sinuous snake bodies to imagining bigger ones carving out the meandering banks of rivers..

Also, a shame they nixed the name Montypythonoides.

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