Veldmeijer, Witton and Nieuwland (2012) have a relatively new book out (Fig. 1, well… it just recently came to my attention), “Pterosaurs, Flying Contemporaries of the Dinosaurs.” And, like Witton (2013), this book presents the same problems in a gorgeous and easy-to-read fashion.
Just a few pages will suffice for this review, but the whole book is available online here.
Problem # 1.
The authors nest pterosaurs between plesiosaurs and crocodiles (Fig. 2). Folks, I’m not making this up, but I think they are. Certainly this is the result of a dartboard throw, because no comprehensive phylogenetic analysis would ever produce these results. Rather, you can find the tested and verified nesting of pterosaurs here at the large reptile tree.
What Bennett 2006 identified as a baby Germanodactylus, Veldmeijer et al. identify as a baby Pterodactylus (Fig 3). When we get back to reality, phylogenetic analysis nests it is as an adult of its own genus and clade, not even in the lineage of either more widely known genus. The little one is SoS 4593 (formerly PTHE No. 29 III 1950, No. 9 of Wellnhofer (1970). If it looks like a little Scaphognathus, that’s because it is derived from little scaphognathids that were likewise reducing the tail. Bennett, Witton, Veldmeijer all have bought into the hypothesis of allometry (morphological change) during ontogeny, ignoring the proof for isometry during ontogeny in pterosaurs in Zhejiangopterus and embryo pterosaurs, like Pterodaustro.
Sadly, like a droopy dinosaur tail, these pterosaurs (Fig. 4) continue to have bat-like, deep chord wing membranes, for which there is no evidence whatsoever. All the evidence proves that pterosaurs had a narrow chord wing membrane, like the added insets show.
Finally, the authors offer a tracing from Wellnhofer 1991, of a quadrupedal walking pterosaur. I often like to place the trackmaker into the tracks (not in front of them – Fig. 5) to see how carefully the artist has drawn the match. In the lower drawing, note the width of the track does not match the length. On another aspect going back to the original drawing, It’s best, when trying to match trackmakers to tracks, to elevate at least one or two and maybe three of the feet, leaving only one planted, not all four, as shown here (Fig. 5). When all four are implanted the animal has stopped. When two limbs are raised it is in the process of making tracks.
It’s also valuable to animate the walk in order to work out all the problems. In figure 5, for instance, it is difficult to see how such a crouched over pterosaur could make such a long stride. It’s also difficult to imagine the order of limb placement.
If Veldmeijer et al. had just taken the time to match a real pterosaur to a real track they would have found what I found, that the only way to make it work is to elevate the back bone, as in this animated trackmaker that fits every step (Fig. 6).
Veldmeijer AJ, Witton M and Nieuwland I 2012. Pterosaurs, flying contemporaries of the dinosaurs. online here.