Tell me something new about basilisks, puh-lease

There just haven't been enough squamates around here lately (well, apart from the anguids). Because I have guilt, here is a good photo of a beautiful animal: a Plumed basilisk Basiliscus plumifrons. Thanks to their striking appearance, basilisks are often featured in books and on TV, but people only ever say the same two things about them: (1) that they have striking display structures like those so obvious here, and (2) that they can run (bipedally) across the surface of water. Yeah yeah, I've heard all that before - tell me something new, puh-lease!


I have to admit that I can't: all the books all say the same stuff. Namely: basilisks are large green iguanians from Central and South America (they've also been introduced to Florida for some reason); they're arboreal, frequenting vegetation around ponds, streams and rivers; they can run bipedally; and rectangular toe fringes allow them to run across the surface of the water for a short distance (see Glasheen & McMahon 1991, 1992). Laurie Vitt proposed (in Pianka & Vitt 2003) that the toe fringes that allow 'water walking' are exaptations. Their initial evolution presumably occurred because they're advantageous amongst arboreal species, and they've since been co-opted by a group that - like quite a few other arboreal lizard groups - has learnt to drop into water when menaced by predators [image below from wikipedia. Photo at top courtesy Tina Whitlock].


Of the four species (Common basilisk B. basiliscus, Red-headed basilisk B. galeritus, Plumed basilisk and Striped basilisk B. vittatus), B. plumifrons is thought closest to B. basiliscus. I won't even begin to discuss the affinities of basilisks within Iguania, as I don't have time (see Frost et al. 2001), but they've generally been regarded as part of Corytophanidae, a group that includes various arboreal iguanians and may or may not be closely allied to (or part of) the clade that includes anoles. Incidentally, a group of entirely extinct iguanians from the Eocene and Oligocene of Europe and Oligocene of North America - the messelosaurines - are apparently part of Corytophanidae too (see Rossmann 1999a, b, 2005), though I'd like to see more testing of this hypothesis. Rossmann (1999a) proposed that corytophanids originated in Europe, and ended up in South America following dispersal to North America.

As for the crests... the posterior cranial crest is supported by a sheet-like bony parietal crest, and I'd like to know if there's any bone supporting the dorsal and caudal crests. Does anyone know?

For previous Tet Zoo articles on iguanian lizards see Amazing social life of the Green iguana and Ermentrude the liolaemine.

Thank you Tina, again.

Refs - -

Frost, D. R., Etheridge, R., Janies, D. & Titus, T. A. 2001. Total evidence, sequence alignment, evolution of polychrotid lizards, and a reclassification of the Iguania (Squamata: Iguania). American Museum Novitates 3343, 1-38.

Glasheen, J. W. & McMahon, T. A. 1992. A hydrodynamic model of locomotion in the basilisk lizard. Nature 380, 340-342.

- . & McMahon, T. A. 1992. An analysis of aquatic bipedalism in basilisk lizards. American Zoologist 32, 144.

Pianka, E. R. & Vitt, L. J. 2003. Lizards: Windows the Evolution of Diversity. University of California Press, Berkeley.

Rossmann, T. 1999a. Messelosaurine lacertilians (Squamata: Iguanoides) from the Palaeogene of France and North America. Neues Jahrbuch fur Geologie und Paläontologie, Monatshefte 1999, 577-592.

- . 1999b. "Crotaphytus" oligocenicus (Holman, 1972), (Squamata: Iguanoidea) from the Oligocene of Saskatchewan, reinterpretation and some paleobiogeographical implications. Neues Jahrbuch fur Geologie und Paläontologie, Monatshefte 1999, 186-192.

- . 2005. Nachtrag zur Osteologie und Palaobiologie von Geiseltaliellus longicaudus Kuhn (Lacertilia, Iguanoidea) aus dem Mittleren Eozän (MP 11) der Grube Messel, nahe Darmstadt. Courier Forschungsinstitut Senckenberg 255, 225-236.


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I saw something like this last week in Fort Lauderdale, Florida on top of a tile roof. There are FAR to many types of lizards running around loose down here to keep track of.

By thylacine (not verified) on 16 Jan 2009 #permalink

At least we can say that we sorta understand how they run on water- papers by Glasheen and Hsieh showed that nicely, e.g.:

and this inspired a water-running robot!

[from Darren: held up by spam-filter!]

You want something new about Basilisks? Okay, here goes...

It seems those crests on B. basiliscus might be used for display.

There, I've said it, my own personal guess. If you don't like it, why don't you go study it yourself?

They have an astonishing ability not to turn anyone to stone.

By Andreas Johansson (not verified) on 16 Jan 2009 #permalink

"I won't even begin to discuss the affinities of basilisks within Iguania [...] they've generally been regarded as part of Corytophanidae, a group that includes various arboreal iguanians and may or may not be closely allied to (or part of) the clade that includes anoles."

And there, ladies and gentlemen, you have TZ in a nutshell! :-)

There's a bunch of suggested links between Messel fauna and South American fauna, but some of these putative relations were contested. Messelornithids, the enigmatic "pseudo-anteater" Eurotamandua, cariamids and another ones...
They could have crossed the North Atlantic Paleogene paratropical belt (America-Greenland-Europe) from Europe to southernmost North America (some tropical refuge in Mexico or Central America, still not explored), later to South America.
Or... the missing link could came from Africa (Gondwanan origin?) or from India (that share many faunal traits with South America: titanosaurids, abelisaurids, toads, lizards, gondwanatherians, etc)

By J.S. Lopes (not verified) on 16 Jan 2009 #permalink

New basilisk news?

A new study recently published in the Journal of Arcane Genetics (vol 196 p83) revealed that the last known population of Amur Basilisks (a sub-species of the Asiatic Lion Basilisk) is no such thing. The animals are instead a population of Atlas Mountain Basilisks, a sub-species of African Lion Basilisk once thought to have been driven extinct back in the 12th century.

It turns out the Amur Basilisk did go extinct in the 12th century. A local wizard then transported the last existing pack of then endangered Atlas Mountain Basilisks to the Amur region so he would have something to show his visitors.

There were papers written concerning this possibility, but since teleportation and gating wasn't supposed to be that good back then, such work was considered ludicrous at the least.

Or were you talking about real world basilisks?

I saw basilisk lizards for the first time while I was a high school exchange student in Costa Rica. I had read about them, but was still flabbergasted to see them do the bipedal Jesus lizard trick on a small rain forest stream. I remember rushing to tell my friends about it, but they couldn't be bothered to show an interest. They were also oblivious to my reports of sloths and leaf-cutter ants. All they cared about was the lower drinking age, sports, and hooking up with each other. Costa Rica was WASTED on them!

A couple of years ago I went back to Costa Rica and once again was able to obserce basilisks in the wild. They are really cool critters. I did not know that there were introduced populations in South Florida. I might have to head down there and take a look.

hmmm. A silly question. Has anyone considered doing a comparison of the basilisk hip structure and that of the earliest archosaurs (and allies)?

The transition to bipedalism in diapsids hasn't happened that often after all.

Gilmore (1919) writing about Dimetrodon says: "The one living lizard which throws some light on this problem is Basilicus plumifrons from tropical America, which has the crest on the back; though not so high or extensive as in Dimetrodon, is nevertheless supoorted by the elongated spinous processes of the vertebrae..." The full paper is on Google Books.

Unfortunately there's no figure of the skeleton, but surely some TetZoo reader has a basilisk skeleton handy right?

Gilmore, C. W. 1919 A mounted skeleton of Dimetrodon gigas in the United States National Museum, with notes on the skeletal anatomy. Proceedings of the United States National Museum No. 2300

Since we're sharing basilisk information, I would like to point out that the Basilisk was one of the best creatures to go to battle with in the good ol' eighties computer game Archon (although my most favourite creature was its opposite number, the Unicorn).

Archon: my favourite beast was the phoenix, though the banshee was also pretty cool. Thanks to all for comments. Busy right now watching a documentary on the wildlife of the Western Ghats - - it includes data on a large grey cat, as yet unidentified.

No new information but a suggestion: you could put the basilisk in a new section called "Zoological Oddities" along with other weird critters like the Archer Fish and the Bombardier Beetle! (I'm being facetious, of course, but I've got nothing else.)

By Raymond Minton (not verified) on 16 Jan 2009 #permalink

Darren, Darren, and you call yourself British and ignore the language that ruled the Isles before the Saxons? It's bansidhe. ;)

By Jaime A. Headden (not verified) on 16 Jan 2009 #permalink

Does anyone know if they can and do swim? Do they swim like a croc swims, first with the limbs, then the tail? The tail is hefty and the dorsal ribbed ridges may help with balance and speed aerodynamically while running, similar in function to early feathers on swift bipedal therapods?
feather for display?

I've once seen a documentary in which a basilisk attacked and ate baby iguanas. Is that true?

Also, their dorsal crests remind of David Peter's pterosaur "reconstructions". Any news from him?

DDeden, they certainly can swim. I'm not sure about the exact mechanics of limb and tail use, but this video and this photo might offer some insight (albeit limited because of the shallowness of the aquarium and the murkiness of the river).

Re: iguana hatchlings, Carlos, that certainly sounds within the realm of possibility.

Carlos said...

I've once seen a documentary in which a basilisk attacked and ate baby iguanas. Is that true?

In the wild they're reported to eat frogs and insects in addition to fruit, so I'd assume that smaller lizards would also be on the menu. This is also conceivable given their size (to 70 cm or so).

Oh, and Will Baird asked...

hmmm. A silly question. Has anyone considered doing a comparison of the basilisk hip structure and that of the earliest archosaurs (and allies)?

The transition to bipedalism in diapsids hasn't happened that often after all.

Certainly not a silly question. As it happens, a few people have looked at bipedalism in basilisks and other lizards, and others have then used this data to make inferences about bipedality in archosaurs and other fossil reptiles (e.g., Rieppel 1989, Hamley 1990, Renesto et al. 2002). Synder (1949, 1954, 1962) did much of his work on basilisks, and subsequent studies on lizard bipedality always cite this work. Incidentally, bipedalism does not make lizards faster runners.

Refs - -

Hamley, T. 1990. Functions of the tail in bipedal locomotion of lizards, dinosaurs and pterosaurs. Memoirs of the Queensland Museum 28, 153-158.

Renesto, S., Dalla Vecchia, F. M. & Peters, D. 2002. Morphological evidence for bipedalism in the Late Triassic prolacertiform reptile Langobardisaurus. Senckenbergiana lethaea 82, 95-106.

Rieppel, O. 1989. The hind limb of Macrocnemus bassanii (Nopcsa) (Reptilia, Diapsida): development and functional anatomy. Journal of Vertebrate Paleontology 9, 373-387.

Synder, R. C. 1949. Bipedal locomotion of the lizard Basiliscus basiliscus. Copeia 1949, 129-137.

- . 1954. The anatomy and function of the pelvic girdle and hind limb in lizard locomotion. American Journal of Anatomy 95, 1-45.

- . 1962. Adaptations for bipedal locomotion of lizards. American Zoologist 2, 191-203.

I can't contribute anything new bioogically. However, re origins of the word basilisk: 1250â1300; ME < L basiliscus < Gk basilÃskos princeling, basilisk, equiv. to basil(eús) king + -iskos dim. suffix; allegedly so named from a crownlike white spot on its head.

I am going to go on a limb and say that, based on various photographic sources and apparent sexual dimorphism, as well as cranially-crested but dorsally uncrested specimens, there is no vertebral support of the dorsal "frill", and that it is a dermal appendage.

By Jaime A. Headden (not verified) on 17 Jan 2009 #permalink

From Savage, J.M. 2002. The Amphibians and Reptiles of Costa Rica. U Chicago Press. ISBN 0226735370, 9780226735375. Page: 427 (and also available on Google Books)

Relevant excerpt:

"Small juveniles and small adult females show no evidence of these crests, which involve the gradual elongation of the neural spines of the dorsal and anterior caudal vetebrate and the elaboration of a fleshy vertical fin covered by thin smooth scales. The crests, when fully developed, have nerual spines that may be 50 to 60 mm long and curve gently posteriorly."

As with Neil's reference, there is no skeletal picture accompanying the description. Though there is a diagram showing the various degrees of head crest formation in _Basiliscus_.

The aptly named "sailfin chameleon" (Chamaeleo montium_) also exhibits a vertebrally supported sail.

DDeden, I've come across a video clip of a young basilisk fleeing across a Floridian swimming pool. After running out of momentum as it runs across the pool's surface, it clamps its limbs against its side while propelling itself forward with rapid lateral undulations.

In further basilisk news. . .

Inspired by a lab accident at Columbia University's School of Medical Dweomercrafting, a five year study at Boston University's Neuroheka Lab has shown that the Bluegrass Basilisk (a relative of the Common Frogmouth Basilisk) does indeed interfere with nerve function by interrupting uptake at the synapse. Contradicting the hypothesis that nerve function was disrupted by blocking transmission down the axon.

(Real world? Still real world? And here I've got some great imaginary stuff. Poofle.)

Owl Mirror,

The creator of your world is not subject to your laws.

Besides, Games Andes Redshift does not apply in this case insofar as the world it was written for is not the world I am writing about.

In any case, the people living in my exercise know about basilisks, know about basilisks paralyzation, know about basilisk paralyzation treatment, and spend millions of dollars on bogus treatments because certain types of basalisk paralyzation have no effective treatment other than time. Therefor clearance hasn't a dang thing to do with it.

Never assume that the rules of your sub-creation have to be the rules of other sub-creations.

Apologies for digging up such an old post, but I am slowly making my way back through the archives of this top notch blog. In case anyone is interested, there are two Australian lizards - the Eastern Water Dragon and Gippsland Water Dragon, that are also able to run across the surface of the water. This is generally observed in juveniles but also for short distances in adults. The Australian Water Dragons do not possess the same toe fringe as the basilisk (though are quite similar in many other ways). Apparently the Chinese Water Dragon, another member of the genus Physignathus is also capable of running across water.

Really, what is the exact reason that the Common Basilisk was introduced to Florida??
It was introduced as a feral species but was there really any reason behind it?
There is absolutely no research I can find on this issue. ):

By Shirish N. (not verified) on 04 Jun 2010 #permalink