Wednesday Wonders: Cearadactylus

13 05 2009

“Grant was thinking these weren’t ordinary pterodactyls. They were too large. They must be cearadactyls, big flying reptiles from the early Cretaceous. When they were high, these looked like small airplanes. When they came lower, he could see the animals had fifteen-foot wingspans, furry bodies, and heads like crocodiles’. They ate fish, he remembered. South America and Mexico.”

So the late Michael Chrichton describes the bizarre Cearadactylus atrox, in what is undoubtedly the animal’s most famous appearance in any fictional medium during the final third of his now-classic novel,” Jurassic Park” (and considering its status as such, I’ll ignore his replacement of the word ‘pterosaurs’ with ‘pterodactyls’) . Though the scene in question was never adapted for the original film, it did inspire the notorious aviary scene in the series’ mediocre third installment wherein the lead (reptilian) role was given not to Cearadactylus but to its far more recognizable distant relative, Pteranodon longiceps, which was erroneously depicted with re-curved teeth (a particularly unforgivable mistake given the fact that “Pteranodon” means “toothless wing”).

Aside from it’s comparatively iconic image, one would wonder why Spielberg and company selected Pteranodon over Cearadactylus when the latter clearly suffers from no shortage of teeth, as this photograph (which represents the creature’s only known skull) exquisitely demonstrates. According to The Pterosaur Database,

“This pterosaur is known from a single skull of about 57cm in length from the Santana Formation, north eastern Brazil. The jaw is articulated and uncrushed, showing the position in life.”

Cearadactylus skull reconstruction.

Cearadactylus skull reconstruction.

However, much of the skull’s posterior is missing, given that an erosional line cuts through the holotype’s nasopreorbital opening (the large hole in the skull which sits in front of the eyes in pterosaurs), orbit (eye socket), and lower temporal fenestra, everything above which has been destroyed and erased. Since this region is missing, it’s possible that Cearadactylusmay have sported a crest, but given the fact that most of its closest relatives (which will be outlined later) were crestless, it doesn’t seem very likely.

Cearadactylus was almost certainly a pterodactyloid pterosaur, as evidenced by the considerable size and overall shape of its skull. Specifically, it appears to have hailed from a group known as the ctenochasmatoids which, as David Unwin explains in his recent book “The Pterosaurs: From Deep Time”, are defined by:

“A highly modified skull design in which the quadrate bone, upon which the lower jaw hinged, lay in an almost horizontal position, and a neck that was extremely long, achieved not by adding more vertebrae, as birds do, but by stretching several of the existing ones into long tube-like structures.”

Some of the most famous ctenochasmatoid genera include the name-bearing Ctenochasma, the famed Pterodactylus, and a creature to which Cearadactylus is likely a close relative, Gnathosaurus. Most ctenochasmatoids are depicted as shore-dwelling, heron-like predators wading in bodies of water to either sieve for prey or snatch it depending on their dentition. Given the appearance of Cearadactylus‘ teeth and jaws, it’s not very difficult to guess to which school of action the beast subscribed. 

Cearadactylus reconstruction

Cearadactylus reconstruction

When one steals another glance at that magnificent maw, one can’t help but note a striking similarity to the long, crocodile-like, snouts which characterise the spinosauridae and are widely believed to have served as tools with which to capture and hold slippery fish. Indeed, the proportions of Cearadactylus‘ jaws and teeth scream in testimony to this resemblance and thus it comes as no surprise to learn that most pterosaur experts have attributed them to an identical (or at least very similar) function. While it’s obvious that not all pterosaurs were strictpiscivores (fish eaters), it’s fairly safe to assume that this title may be handed to this particular genera. Peter Wellnhoffer, one of the world’s most foremost pterosaur workers, expands on these observations in his book “The Illustrated Encyclopedia Of Pterosaurs”:

“A particular feature of Cearadactylus is its powerful dentition. The front teeth are much longer and much stronger than the back ones. When the snout is closed, there was a gap in the front area. The long front teeth, set in jaws which broaden to a spoon shape at the front, suggest an excellent grip when catching slippery fish.”

This infamous dental arsenal was the result of tens of millions of years of evolution within the gnathosaurine branch of the ctenochasmatoids. According to David Unwin:

“Their teeth [became] larger and largerand steadily fewer in number. These changes point to a shift in diet toward bigger prey items, with a switch at some point from invertebrates back to fish. In this case, the trend culminated in Cearadactylus, a large 3-to-4 meter (10-to-13-foot) wingspan gnathosaurine.”

Cearadactylus shared its range with a plethora of weird and wonderful pterodactyloids, including Tropeognathus, Anhanguera, and Tapejara, all of whom lived from approximately 120 to 112 MYA. One can only hope that more material of this creature is eventually located, given the pterosaurian propensity for shattering our interpritations of previously-known species via the discovery of relatively complete new specimens.

May the fossil record continue to enchant us all!

P.S: I realize that reptiles have monopolized the new ‘Wednesday Wonders’ segment thus far. Rest assured, fellow paleo-mammal fans, non-reptilian creatures will get their chance in the spotlight soon enough.

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6 responses

13 05 2009
Zach Miller

Hey now, birds are reptiles, too! I would like to see some non-mammalian synapsids up in here. Some of those buggers are real oddballs!

Loved the article. Ctenochasmids are really cool in their diversity. The toothy trend culminated in, of course, Pterodaustro, though it was present to a lesser degree in Ctenochasma and perhaps Beipiaopterus. In fact, should one be so bold as to invoke a direct lineage for evolution, you can see the development of filter feeding through Pterodactylus to Cearadactylus to Ctenochasma to Pterodaustro.

Of course such a linear progression is highly unlikely, but it provides a good general model for how filter feeding might evolve. One wonder if, given a few more million years, spinosaurs would have adopted similar strategies.

14 05 2009
tanystropheus

Hey, Zach!
Yes, I do recall reading that phylogenetically birds should be considered reptiles and have updated the post accordingly. Out of curiosity, why should birds fall into this categorization but not mammals considering that both stemmed from reptiles?

I’m also quite a large fan of non-mammalian synapsids…in fact, I’m considering attending the University of Toronto for grad school to study them under Dr. Reisz should I decide to specialize in them…but alas, this is several years down the road. I was planning on doing an Ophiacodon post at some point, assuming I can locate enough resources.

Your question regarding if spinosaurs would have evolved the way of Pterodaustro is intriguing…perhaps this could be fodder for one of your ‘hypothetical evolution’ drawings. Just a thought.

14 05 2009
Zach Miller

Hey, that’s not a bad idea.

Okay, reptiles. As you know, Amniota is made up of two branches: Synapsida and Sauropsida. Sauropsids contain anthracosaurs, parareptiles, the old “anapsid” guild (no longer includes turtles), and diapsids (among a few other wierd group). The term “reptiles” only concerns the crown: Diapsida. That means sauropsids, squamates, and archosaurs.

Some workers don’t even use the term “reptile” anymore because of the intellectual baggage it carries. I still like it, though. However, it’s restricted to diapsids, basically. Turtles are diapsids now, by the way. I can get you more info on that if you like.

Anyway, mammals are synapsids, and synapsids aren’t reptiles. That old term “mammal-like reptile” is horribly wrong. Any shared characteristics between Dimetrodon (a basal synapsid) and Petrolacosaurus (a basal sauropsid) are merely plesiomorphies. Synapsids might not have even had scaley skin.

Actually, check out the new Art Evolved! show (if you haven’t already) for a good look at the diversity of Permian synapsids. There are two posts below the show itself where Craig and I discuss what a non-mammalian synapsid is. And veeeery early in my blog history (first two months, maybe), I rant about the term “mammal-like reptile.”

So that’s the short story. Birds are reptiles because they’re diapsids. They’re also dinosaurs. And archosaurs. You get the idea. 🙂

15 05 2009
tanystropheus

Many thanks for clearing this up, it had been bothering me for some time!

26 06 2009
My Summer Reading List « The Theatrical Tanystropheus

[…] know, I know. I’ve already cited this in an earlier post about Cearadactylus. However, though I’ve skimmed it repeatedly, I haven’t actually […]

13 10 2010
Alex bb

Hi There,

I was wandering if you would be able to tell me where you got the Cearadactylus skull reffernce model from. I work for a TV comapny and we think we might be able to use it ina film we are producing.

best Alex

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