sábado, 7 de fevereiro de 2009

Mark Witton vs John Conway

For those interested in pterosaurs, you might recognise these two artists, which seem to be on the leading positon on the pterosaur imagery/paleobiological speculation business (well, Mark is at least; John seems to have turned off, although he still seems to be alive). The whole purpose of this waste of time its too see which of these wonderfull artists depicts pterosaurs better and thus to see which one is decent/mentally sane/whatever.

Anyway, since I haven't asked for the permission of using their pictures, use the following links:


And now we shall begin.

Favoured species

Mark Witton depicts many different pterosaur species; in fact, there not a single pterosaur group he missed. I still pity the fact that he largely ignored ctenochasmatoids (aside from Pterodactylus & Pterodaustro, he didn't portrayed any other specie, which is a shame, because I really want to know his opinion on Cycnorhamphus and Cearadactylus), and he still rarely does non-pterodactyloid pterosaurs (aside from Dimorphodon). From the number of pictures he did, the pterosaur family he focused the most on was Azhdarchidae, and, truth to be told, it was quite predictable; after all, he was one of the two people responsible for showing the world they weren't skimmers but stork-like generalists, right? His first pictures of such animals were somewhat inaccurate (the first depicted them with a neck too thin and hunting in shallow water, the second showed a horrendous skinny thing, with thin wings in addition to the thin neck, and the third shows something akin to his first image but with a neck still too thin and taking off on a bird like fashion), but afterwards his were considered the best depictions of these pterosaurs on the net.

John Conway, on the other hand, seems to have a liking on a rival linage of flying reptiles, the Ornitocheiroids. His favourite species seem to be Anhanguera, Pteranodon and Nyctosaurus, which represent clades Ornitocheridae, Pteranodontidae and Nyctosauridae (if the later is distinct of the second, obviously). Other pterosaurs, however, received some attention from him; the ctenochasmatoid Pterodactylus, and the tapejarid Sinopterus (although he seems to regard Sinopterus and Nemicolopterus as distinct, the fact is that the later is a juvenile of the first, so...), however, still received some attention from him.

Pterosaur wing designs

Mark depicts pterosaurs with their patagium connecting to their legs/feet. This view, often considered quite old and unoriginal (after all, bats too have their wing membranes like that), might actually be very accurate, because evidence shows that many pterosaurs had their wing membranes connecting to their legs/feet, and quite possibly all pterosaurs were like this. The propatagium is well shown in his earlier pictures, with the pteroid rised and shown to be supporting two membranes: one between it and the shoulder and the other between it and the hand. Nowdays, though, his flying reptiles seem to have a smaller and more typical pteroid, with no membrane connecting it to the hand, thus having a single, more "traditional" propatagium. The uropatagium in his pterosaurs is quite big in basal species, to the point that it even connects the two legs, but that excludes the tail. In pterodactyloids, it is reduced to two small membranes running along both legs, which, according to him, is one of the reasons advanced pterosaurs had a better ground locomotion than their ancestors.

In John's pterosaurs, the wing structure is quite different. He depicts his pterosaurs with the wing membranes connecting to the hips, giving their wings a more avian shape. At the most they connect to the knees, but no further. The propatagium is pretty much as in birds; the pteroid is hardly visible, and he seems to think it might be able to inflate, like the ones of pelicans and some other birds. His uropatagium is composed of two distinct membranes running along the legs as in Mark's, but they are much more developed and almost make the back limbs resemble the tail feathers of birds like kites and frigate birds, and they could have had the same function. The feet are also webbed, further stressing the role of the feet in steering. The actinofibrils seem also to be more visble in his pterosaurs, making their wings more similar to those of birds.

Lifestyle depictions/implications

Mark presents a vivid alternative to the steryotypical view that pterosaurs are sea bird analogues. Based on actual evidence overlooked by nearly everyone else, he managed to show the possible real lifestyles of many pterosaur species. For instance, rather than fish eaters, his tapejarids are galliforme analogues, running or climbing in search of animal and plant matter (though his first picture of this group depicts a sea bird like animal, and the second a falcon like predator; however, at the time he wasn't as wise as he is now). Dimorphodon passed from a puffin like fish eater to a tree climbing predator, and, as we all know, azhdarchids are now seen as terrestrial thanks to him. The wings of his pterosaurs also reflect their lifestyles; terrestrial forms have shorter, broader wings, while his ornitocheiroids, while still having their membranes attaching to the legs, have much longer wings, thus resulting on a thinner wing shape. Overall, his pterosaurs are as diverse as our birds.

John Conway, on the other hand, offers a more limitated view on pterosaur ecology. Aside from Germanodactylus (portrayed as a small opurtonist), Pterodactylus (portrayed as a shore bird like prober) and Nemicolopterus (depicted as a robin like omnivore), and possibly Zhejiangopterus (seen on the ground, though no particular lifestyle is atributed to it), all of his pterosaurs seem to be sea bird analogues, using their thin wings to soar over coasts or seascapes. His Quetzalcoatlus, seen flying over a lake and with a neck quite shorter than Mark's, seems to be a skimmer (though its size seems to suggest that its a baby, not a full grown pterosaur), and his Sinopterus is implied to be a seagull or skimmer like form.


As a whole, I prefer Mark Witton. While John Conway has beutifull pictures, they are overall wrong in the anatomy and lifestyle of pterosaurs. Though they are too beutifull to go to waste, and certainly original, depicting pterosaurs as more bird like than bat like, they sadly lack the accuracy of Mark's works. I wish he uploads something new soon though; I'll ignore the wing membranes (as I always do; they look better in the way he depicts them anyway) as long as he shows pterosaurs that aren't sea bird like.

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