Showing posts with label scaphognathus. Show all posts
Showing posts with label scaphognathus. Show all posts

Sunday, September 11, 2011

Scaphognathus Illuminated

You may remember that I went a bit batty over Scaphognathus crassirostris this year (here, here, and here).

In the Vintage Dinosaur Art post about S. crassirostris, I featured several reconstructions that used the same pose. It's rare that it's repeated nowadays, but I was mighty tickled to see this shared on Twitter today:
pterodactyl

Yup, that's the pose. It's a light painting by artist Darren Pearson. Read more about his work and his series of dinosaur light photos at Petapixel.

Wednesday, June 15, 2011

Goertzen's Case for the Historical Scaphognathus

In the first half of this post, I wrote about the shaky relationship between cryptozoological research and science, as well as the way creationism worms its way into the equation. I also introduced John Goertzen's paper The Rhamphorhynchoid Pterosaur Scaphognathus crassirostris: A "Living Fossil" Until the 17th Century. Today, we'll dig into it and look at the evidence presented.

First, a summary of what we know about Scaphognathus. A denizen of Late Jurassic Germany, it was a small pterosaur of the family Rhamphorhynchidae. The Pterosaur Database writes,
Three near complete specimens have been preserves [sic] along with some fragmentary remains, almost exclusively from the Solnhofen Limestone of Bavaria. Typically, this species had a skull length close to 12cm and a wingspan of about 90cm. A characteristically broad jaw, relatively short tail and short wings in comparison to other rhamphorhynchoids and a broad sternum.[PDF]
For those allergic to the metric system, the wingspan came to about three feet, making the animal about the size of your average hawk. The head was about four inches long. It's highly likely that Scaphognathus bore a covering of the hair-like structures called pycnofibers, as the closely related Sordes has been found to possess them (and it's likely that all pterosaurs did). Like their cousins the dinosaurs, where pterosaurs were once believed to have been lizard-like creatures, new discoveries and technological advancements have revealed them to be unique creatures not like anything that we share the Earth with today.

Scaphognathus crassirostris Holotype, 1831
The S. crassirostris holotype. From my Flickr set dedicated to the beastie.

I made my best effort to read Goertzen's paper objectively, but this isn't entirely possible. His claim has little prior plausibility, and therefore he has a higher mountain to climb than someone who makes a claim that doesn't contradict centuries of well-supported scientific evidence. The major failing of most cryptozoological claims is that the evidence is weak, relying too heavily on personal accounts. A good story can be intriguing, but this doesn't amount to evidence. Knowing that the writer's goal is to demonstrate the existence of  pterosaurs during human history based on artifacts and ancient writings, a stiff dollop of skepticism is warranted and outright cynicism is understandable. Unfortunately, Goertzen stumbles at the very outset. After a brief description of the two fossils of Scaphognathus, he writes,
Because the S. is the only rhamphorhynchoid pterosaur with a head crest, ancient artifacts enable us to tell what the soft tissue of the head crest looked like and identify ancient S. representations with a high degree of confidence.
Despite putting on a crisp white lab coat labeled "scientist" in the paper's opening, he's just given up all pretense to rational thought. It's irresponsible to imply that the head crest of Scaphognathus has been confirmed beyond a shadow of a doubt. It hasn't. As Palaeocritti's page on the pterosaur states, there "is no direct evidence of a crest like the one shown on the illustration below, and this is merely inferred from the presence of a flange of bone above the anterior portion of the rostrum which might have supported a fleshy crest," similarly stated in Buffetaut and Mazin's Evolution and Palaeobiology of Pterosaurs. The Dmitri Bogdanov illustration shared at Palaeocritti is included below for reference.


Illustration by Dmitri Bogdanov, via Wikipedia.

But I'm willing to give Goertzen space and allow that if a line of rhamphorynchoid pterosaurs survived the end-Jurassic extinction, and then the K-Pg extinction, some of them may have evolved a head crest or whatever other bodily adornments folks want to find in the archaeological and historical record. Those pterosaurs may have survived the intervening 65 million years. And over all of that time, by chance they may have avoided preservation in the known fossil record. Their habitat preferences may have changed so they became isolated in areas that aren't likely to lead to fossilization. It's a lot of if's and maybe's to build on, but it's not completely out of the realm of possibility. However, my charity is probably misplaced. Goertzen writes (all emphasis his),
I need to stress that the methodology of Paleocryptozoology is not necessarily to find artifacts that look like modern reconstructions of scientists based on fossils. Indeed, that may be helpful and there may be some accuracy with some of the scientific reconstructions. However, the best method for success is to search for distinct morphological features that are difficult to explain by any other means than that a particular fossil species was observed and accurately described or depicted by its witnesses. An example of a distinct morphological feature is the tail vane of some rhamphorhynchoid pterosaurs. Also, it could be a distinctive skull like that of a Dimorphodon. ...For the S., the distinctive feature is a rhamphorhynchoid pterosaur with a head crest. The S. is the only long-tailed pterosaur presently known from the fossil record with that feature. That will be examined in the present study.
I can clear a wider path for Goertzen, but he's already committed to a pretty narrow one. He sees a crested Scaphognathus in all sorts of odd places, including both written accounts and visual representations on seals, coins, and maps. Beyond a basic description of a reptilian creature with wings and a head crest (with no pycnofibers, it must be noted), the descriptions and drawings vary so widely that only wishful thinking can cobble them into a single, consistent creature. Of course, this is the sort of thing a biblical literalist is adept at.

The Coins and the Egyptian Seal
Goertzen sees crude images of Scaphognathus on a Roman coin, but the  image provided is so low resolution, it's as if he's trying to make the reader work to make out a pterosaurian form in the squiggles and blotches. Luckily, over the years better versions have been made available, such as the one on page 181 of Wayne Sayles' Ancient Coin Collecting IV. The two serpents pulling a chariot sure don't look like Scaphognathus to me. He correctly identifies the driver of the chariot as Triptolemus, a mythological figure. Certainly, this mythological figure might employ steeds with an similar founding in mythology? Or is it more likely that the ancients employed a hawk-sized pterosaur as a draft animal?

On a 1622 German coin, a knight on a horse overpowers a creature that looks like a dragon/ griffin half-breed. Again, it's too large for Scaphognathus. And only a feat of imagination can make it resemble one. Worse yet, two plum chances to make a joke about a pterosaur on a coin sail right by Goertzen. Brother, can you spare a Dimorphodon?

The Egyptian seal he provides doesn't fare much better, and the quality of the image is even worse than the Roman coin. Again, there's the problem of the alleged Scaphognathus engaging in an activity it's probably not suited for. This time, hunting a gazelle. A line drawing is supposed to clear up the matter, but's kind of useless. I personally see a hot dog stand, but my worldview doesn't depend on hot dog stands in ancient Rome, so I'll probably not bother with putting up a website devoted to it.

The Maps
Goertzen provides two 15th century maps which supposedly bear illustrations of Scaphognathus, the 1435 Borgia map and the 1457 Genoese map. Dragons aren't exactly unprecedented in ancient maps; and the Wikipedia article linked here includes an inscription that Goertzen omits. Above a dragon in Asia, a Latin inscription states, "Here there are even men who have large four-foot horns, and there are even serpents so large that they could eat an ox whole." Goertzen seems to take ancient historians and other writers at their word, believing their accounts to be reliable. It's not the sturdiest foundation on which to base what claims to be a rigorous academic essay.

The Sketches
The last form of visual record provided are two sketches of dragons. Goertzen relays the story of the dragon of St. Radegonde, "The Grand Goule," which the second of them is supposed to depict. "This had been encountered previously by those who worked in the monastery. and that monster devoured the monks who, too imprudently, approached its privacy." Now, Scaphognathus is large enough to devour monks. There were certainly large pterosaurs. But Scaphognathus wasn't one of them.

The Personal Accounts
In addition to the visual evidence of ancient artists and artisans, Goertzen provides written accounts he claims describe Scaphognathus clearly. Just as the images above didn't do the trick, I'm afraid that I don't find any of this convincing. Remember how valuable anecdotes are as scientific evidence? They aren't, unless paired with something better. Humans are pretty good at exaggeration and mistakes of perception. Here are what his various naturalists, historians, and other observers saw:
  • "...winged serpents, small in size, and various in form, guard the trees that bear frankincense, a great number around each tree. These are the same serpents that invade Egypt..."
  • "...a small serpent, as long as a palm branch, and thick like a small finger. It has a small piece of skin, like a crest, on its head and, in the middle of the back, two scales placed on one side and the other which serve as wings in order to advance more quickly"
  • "...a cruel kind of serpent, not past four feet long and as thick as a man's arm out of whose sides grow wings much like unto gristles"
  • "...Serpents with wings... they had two legs and small wings so that they could scarce fly. The head was little and like to the head of a serpent. Their color was bright and they were without hair or feathers..."
  • "...winged and flying serpents that can be found who are venomous, who snort, and are savage and kill with pain worse than fire..."
  • "...serpents who are very degenerate and, just as it becomes evening, they fly rising over the land, and rest on the end of their tail, rapidly going into motion."
Even if all of the accounts were consistent - which, despite Goertzen's insistence, they are not - it's more parsimonious to guess that an extant animal explains the sightings of "flying reptiles," and folk legend accounts for their more fearsome aspects. Intriguing stories, but without some sort of physical remains, we just don't know what these animals, with their diverse behaviors, actually were.

Putting it to rest
As I wrote yesterday, I would flip my lid if a living pterosaur was found to exist, but I have to be acutely skeptical of any hypothesis that a large terrestrial vertebrate known only from fossils has survived into the modern day. The scientific evidence of Earth's deep history is overwhelming, and science has established itself as the most reliable way we have to understand the world around us. While people who don't like what science reveals about the world paint it as nothing more than an alternate religion, science does not rely upon faith. What opponents of science brand as faith is actually trust: trust earned by scientists working within a refined system of rational inquiry, strengthened by competition between researchers with differing hypotheses, manifest in technology. What Goertzen's up to here... it's not science.

As someone who does not believe that faith is a path to truth, I find it difficult to don the shoes of a young-earther. If these dragons are supposed to have been living, breathing animals, are we to assume that every mythological creature the thinking ape has invented once walked the Earth, swam the seas, or terrorized the skies? What kind of soul-sucking enterprise is that? Excuse the hyperbole, but in my opinion it's a form of self-hatred, denying humanity its imaginative capacity. Ancient artists and writers are reduced to mere chroniclers of their surroundings, bankrupt of the creativity of invention. As the excellent Bible critic Robert M. Price writes, literalism is a "hollow mockery of the old fundamentalist preaching of the gospel of grace." The sort of literalism Goertzen employs when looking at his "evidence" is, to me, a hollow mockery of mythology. And lest you should be mistaken about whether he's a literalist, read the conclusion of the paper, in which he states that "Pterosaurs were very likely preserved on Noah's ark and survived in Egypt and Europe (and probably elsewhere) until recent times."

It's telling that the title of Goertzen's essay includes the phrase "until the 17th Century," roughly when the age of global exploration and the Enlightenment began. Could it be that the true cause of these cryptids' demise was the clearer vision of the natural world given to us by science? In that case, the last place for the living pterosaur to hide is in the murky fringes of our imaginations.

Massive thanks to Michael Barton, blogger at The Dispersal of Darwin, for helping me access a copy of Adrienne Mayor's Paleocryptozoology: A Call for Collaboration, allowing me to write this.

Tuesday, June 14, 2011

Scaphognathus crassirostris: A Pterosaur in the Historical Record?

Cryptozoology, the study of animals whose existence is not yet proven, has a checkered history when it comes to scientific rigor. While some researchers go about the task with due skepticism, the field also attracts a less reputable element. Some are hoaxers, plain and simple. Some are hopeful believers whose wishes and biases color their perceptions. Some bear a grudge against scientific institutions. Because of all of this, the standing of cryptozoology among scientific disciplines continues to be a heated topic.

The prominence of the Mesozoic bestiary in the popular imagination has naturally spawned legends of extant dinosaurs and pterosaurs. On the dinosaur side of the archosaur family, the Mokele-Mbembe is alleged to be a sauropod who lives in the Congo River basin. Playing for Team Pterosaur is the Ropen of Papua New Guinea. These stories are then seized upon by creationists in efforts to show that the history of life on Earth as reckoned by science is wrong.

One of my favorite venues for responsible discussion about cryptozoology is the Skeptic Magazine podcast MonsterTalk, hosted by Blake Smith with co-hosts Ben Radford, and Dr. Karen StollznowDr Darren Naish joined them for a 2010 episode to share his perspective on the subject of today's post, extant pterosaurs. Speaking about how he and his fellow paleontologists often find themselves on the "front line" of the creationist attack on science, Naish describes a typical encounter with a creationist. Considering paleontology to be an easy target, they'll begin by discussing reconstructions of dinosaurs, springboarding to pick apart perceived weaknesses in the scientific conception of the geological history of the Earth, evolution, and cosmology. This bears out in the creationist museums, which sidestep the overwhelming evolutionary evidence presented by, say, genetics, instead emphasizing the importance of faith and simplistic dioramas of dinosaurs and humans living together. These are designed to play off our inherent difficulty in grappling with deep time: "Millions of years? Get out of here!"

By offering a story in which long-extinct creatures exist during recorded history, cryptozoology is seen to be a sword that finds the chinks in paleontology's armor. In another episode of MonsterTalk from 2009, Dr. David Martill puts it well: "Even if a pterosaur did [survive the K-Pg extinction], it wouldn't alter a jot our perceptions about evolution, or the age of the earth, or any of our scientific philosophies that paleontology has helped develop." There's never been a clear justification for how a "living fossil" undermines the theory of evolution, but still, some creationists seem to be obsessed with this false dilemma.

To wit: The Rhamphorhynchoid Pterosaur Scaphognathus crassirostris: A "Living Fossil" Until the 17th Century, written by John Goertzen with the intention of discrediting evolutionary theory. A recent post in the Vintage Dinosaur Art series dealt with the evolving representations of Scaphognathus, which I described as being somewhat less than notable, as pterosaurs go. I ran across this paper while putting together the post, and I couldn't resist digging into it and seeing the evidence presented. Before that, though, it's probably a good idea to lay out the materials from which Goertzen's argument is built.

The inspiration for Goertzen's paper is a discipline proposed by Adrienne Mayor in an article titled Paleocryptozoology: A Call for Collaboration, published in the journal Cryptozoology in 1989. Mayor is a Research Scholar in Classics and History of Science, described on her university homepage as "an independent folklorist/historian of science who investigates natural knowledge contained in pre-scientific myths and oral traditions." In books such as The First Fossil Hunters, she explores how the bizarre forms of fossils have been studied by ancient civilizations, often being woven into the fabric of the cultures' mythologies (I touched on her ideas in an early post here). There isn't a whiff of creationism in the paleocryptozoology article, so she's hardly to blame for the inevitable hijacking of her term for anti-evolution writings. Aiming to broaden rigorous methods of cryptozoological inquiry and build a bridge between cryptozoologists and classicists, Mayor proposes that some animals we dub "cryptids" might appear in the historical record. Therefore, it may benefit both groups to compile the "scattered and sometimes obscure evidence into one accessible resource." Mayor explains the point of this resource as such:
Working with specialists in other disciplines, paleocryptozoologists could integrate the artistic record with the ancient texts and the modern excavation techniques to determine (1) whether individual or combined features from prehistoric fossils were used as models, or (2) whether "living fossils" might have been observed in historical times.
For a creationist looking to crow about the false dilemma of the living fossil, this paper opens a whole new field to focus on.

The Goertzen paper that inspired this post, as well as other writings of his, appear on a site called "Revolution Against Evolution," so it's a good example of cryptozoology as a weapon in the creationist arsenal. Creationists would do well to realize that a lie (more charitably, a mistake) doesn't become true with repetition. Darwin's theory of evolution by natural selection does not depend on the fossil record, and the more fully fleshed out modern evolutionary theory certainly doesn't. Either evolution deniers understand the science poorly, or they deliberately misrepresent it. Neither option is commendable.

Despite all of the noise surrounding this issue, I have to admit: if given my choice of pseudosciences to grant credibility, I'd be tempted to pick this one (though the potential global benefits of free energy would tug at my altruistic streak). It's in this spirit that I weigh stories of cryptids: hopeful that they might be factual, but bound by the tried-and-true, hard-won methods of science and discouraged by a long history of shabby evidence. Tomorrow, in the second half of this post, we'll get into the nitty gritty of this article and see if Goertzen presents compelling evidence to support the hypothesis that Scaphognathus crassirostris survived long enough for observations of it to have been recorded during human history.


Is this Zdeněk Burian painting plausible after all?
at_sea_by_zdenek_burian
Painting by Zdeněk Burian. Shared by Better than Bad at Flickr.

Monday, March 7, 2011

Vintage Dinosaur Art: Scaphognathus Hangs Out

Pterodactylus crassirostris 1857
Illustration of the restored Scaphognathus crassirostris holotype. From Hugh Miller's The Testimony of the Rocks, 1857.

It's fair to say that Scaphognathus crassirostris is not the most celebrated of the pterosaurs. But the evolution of its popular representations is pretty interesting, and has popped up in a few cool places. The 1857 engraving above is a perfect example of the typical pose that recurred throughout the 19th century.

Scaphognathus crassirostris Holotype, 1831
An engraving of the holotype fossil, described by Goldfuss in 1831.

Scaphognathus was originally described in 1831 by the German paleontologist August Goldfuss, who at the time determined it to be a species of the first described pterosaur, Pterodactylus. During the 1800's, it was shuffled around taxonomically until a second, probably juvenile, specimen was found and Johann Wagner erected its current name in 1858. In January, Dave Hone featured Scaphognathus at Archosaur Musings, writing about pterosaur taxonomy in the years after that first Pterodactylus was discovered. Though Scaphognathus and other early pterosaurs had marked differences from Pterodactylus, they
were put into Pterodactylus based on their even more obvious similarities – these were, after all, obviously pterosaurs. However, once it became clear that there were some important differences, as well and the similarities, then thinks like Dimorphodon and Scaphognathus were separated out into their own genera. This is an extreme example, but the principle is the same and constantly resurfaces.


Pterodactylus crassirostris restored 1836

The "restored version" of Scaphognathus, here reproduced by Buckland in 1836, seems to have cast a spell over early reconstructions of the animal. This pose became the default one used over and over throughout the 19th century, often modified so the wing is in a more extended position.

This 1888 version, redrawn and mirrored horizontally, is from the German natural history text Naturgeschichte Geologie und Paläontologie that was the subject of a Vintage Dinosaur Art post last month.

Pterodactylus crassirostris 1888

Pterodactylus brevirostris, 1836
In this 1836 reconstruction (at right), also from Buckland's Bridgewater Treatises, you can see what I suppose this pose is meant to represent - the animal clinging to a rock face.

Scaphognathus crassirostris 1890

The only early depiction that I could find that strayed from this trend was the one above, from Albert Gaudry's Les enchaînements du monde animal dans les temps géologiques, published in 1890. But it's not too different.

I recently wrote about a collection of paleontology-themed trading cards by the French company Chocolat D'Aiguebelle, and one of them featured a cartoonified illustration of the restored Scaphognathus holotype, though labeled with the generic "Pterodactyle."

Pterodactyle Trading Card from Chocolat D'Aigubelle

My favorite version of this meme, edging out the D'Aigubelle chocolate wrapper, was used for the bookplate of a Dr. Tillfried Cernajsek. Thank you to Matt Celeskey of the Hairy Museum of Natural History website for passing it on to me; I love the woodcut look of it, and it's my favorite of the admittedly small collection of paleo bookplates I've begun.
Dr. Tillfried Cernajsek Bookplate

I've collected these images of Scaphognathus crassirostris, along with others, at Flickr. It's also a fun game of spot-the-mistakes (hint: you can count them on your fingers). I'll be adding more to it as I can, and if you have any other variations of his meme, I'll happily add them to the set.