Pterosaurs

Pterosaurs: Natural History, Evolution, Anatomy

MARK P. WITTON
Copyright Date: 2013
Pages: 304
https://www.jstor.org/stable/j.ctt2jc95p
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    Pterosaurs
    Book Description:

    For 150 million years, the skies didn't belong to birds--they belonged to the pterosaurs. These flying reptiles, which include the pterodactyls, shared the world with the nonavian dinosaurs until their extinction 65 million years ago. Some pterosaurs, such as the giant azhdarchids, were the largest flying animals of all time, with wingspans exceeding thirty feet and standing heights comparable to modern giraffes. This richly illustrated book takes an unprecedented look at these astonishing creatures, presenting the latest findings on their anatomy, ecology, and extinction.

    Pterosaursfeatures some 200 stunning illustrations, including original paintings by Mark Witton and photos of rarely seen fossils. After decades of mystery, paleontologists have finally begun to understand how pterosaurs are related to other reptiles, how they functioned as living animals, and, despite dwarfing all other flying animals, how they managed to become airborne. Here you can explore the fossil evidence of pterosaur behavior and ecology, learn about the skeletal and soft-tissue anatomy of pterosaurs, and consider the newest theories about their cryptic origins. This one-of-a-kind book covers the discovery history, paleobiogeography, anatomy, and behaviors of more than 130 species of pterosaur, and also discusses their demise at the end of the Mesozoic.

    The most comprehensive book on pterosaurs ever publishedFeatures some 200 illustrations, including original paintings by the authorCovers every known species and major group of pterosaursDescribes pterosaur anatomy, ecology, behaviors, diversity, and moreEncourages further study with 500 references to primary pterosaur literature

    Some images inside the book are unavailable due to digital copyright restrictions.

    eISBN: 978-1-4008-4765-5
    Subjects: Paleontology, Zoology

Table of Contents

  1. Front Matter
    (pp. i-vi)
  2. Table of Contents
    (pp. vii-viii)
  3. Preface
    (pp. ix-x)
    Mark Witton
  4. Acknowledgments
    (pp. xi-xii)
  5. 1 Leathery-Winged Harpies
    (pp. 1-3)

    If TV, film, and overzealous internet users have taught me anything, it’s that the prehistoric world was harsh and brutal, and everyday existence was a life-or-death struggle. These terrible landscapes would be unrecognizable to our modern eyes, and only the biggest, nastiest animals survived. Consider, for example, the giant birds that stalked the Earth as recently as two million years ago. Taller than basketball players, they kicked and stabbed small, defenseless mammals to death. The ancestors of our pet cats and dogs wielded sabre teeth and bone-crushing jaws that they used to hunt giant elephants and rhinoceros, themselves armed with...

  6. 2 Understanding the Flying Reptiles
    (pp. 4-11)

    Pterosaurs have a track record of being a rather difficult group of animals to study. Since their discovery well over two centuries ago, they have frequently confounded attempts to comprehend their relationships to other animals (chapter 3), their terrestrial locomotion (chapter 7), or even simply parts of their anatomy (chapters 4 and 5). The history of these specific aspects of pterosaur research will be covered in subsequent chapters but, before we get to these, we will take a moment to familiarize ourselves with a broad outline of the first 230 years of pterosaur studies. In addition to the subsequent chapters...

  7. 3 Pterosaur Beginnings
    (pp. 12-22)

    Trying to ascertain what sort of reptile pterosaurs are is one of the most fundamental goals of pterosaurologists, but pinning down their ancestry has proved very challenging. Much of their anatomy is so significantly different from that of other reptiles that their specific evolutionary origins are obscured. In addition, we have yet to find any “protopterosaur” species that bridge the gap between them and their reptilian ancestors (fig. 3.1). This is a problem that pterosaur researchers simply have to tackle despite its difficulties. Because pterosaurs are extinct, we are reliant on their extant relatives for insights into their likely muscle...

  8. 4 The Pterosaur Skeleton
    (pp. 23-38)

    The heart of pterosaur research beats through our interpretations of their skeletal anatomy. Aside from rarely preserved soft tissues and pterosaur footprints, virtually everything we know about pterosaurs has been derived from studying their fossil bones (figs. 4.1 and 4.2). Accordingly, anyone with a keen interest in these animals must become familiar with their osteology, so we will devote the next few pages to this task. There are two main aspects to cover here: the bones that comprise the pterosaur skeleton, and the unusual construction of the bones themselves. In the interests of brevity and readability, I’ve not cited specific...

  9. 5 Soft Bits
    (pp. 39-55)

    The fossil record is primarily comprised of the hard parts—shells and bones—of organisms. Soft tissues are rarely preserved because they are scavenged and decayed by a multitude of organisms and quickly disappear once an animal dies. If preserved rapidly enough, however, soft tissues can be preserved as sediment impressions or thin mineral films lying alongside fossil bones. The latter are not always visible to the naked eye, but can be detected through the use of ultraviolet (UV) light. This process can transform unassuming specimens into truly fantastic fossils. Undeniably the leader in UV fossil revisualization is Helmut Tischlinger,...

  10. 6 Flying Reptiles
    (pp. 56-63)

    The ability of pterosaurs to fly has almost certainly played a role in propelling them to paleontological stardom while other, equally interesting fossil species are left in the shadows (fig. 6.1). Our understanding of pterosaur flight capabilities, however, is still in its infancy and often rather controversial. Fundamental factors of pterosaur flight mechanics are being debated as our understanding of pterosaur anatomy—and animal flight in general—is continually developing. Consequently, there is still a lot to be learned about this defining pterosaur characteristic.

    We take it for granted that pterosaurs were volant, but why did they take to the...

  11. 7 Down from the Skies
    (pp. 64-73)

    Pterosaurs may also be known as “flying reptiles,” but they were not airborne indefinitely. Eventually, they would have to land in order to feed, rest, or reproduce, and this presented novel locomotory challenges for traversing both land and water. Exactly how pterosaurs did this has been the subject of much debate, and opinions on how well pterosaurs could walk have swung from one extreme to the other in the last 200 years. Until quite recently, most thought that walking pterosaurs had as much grace as a man tangled in a crumpled parachute, scrambling about on weak, flailing limbs and hoping...

  12. 8 The Private Lives of Pterosaurs
    (pp. 74-89)

    As with our opinion of their terrestrial capabilities, our perception of pterosaur paleoecology has changed dramatically in the last few decades. Typically, pterosaurs were assumed to be very birdlike in all aspects of their lives, nesting and growing in a very avian fashion before assuming a seabird-like ecological destiny. More recently, a rather different picture has emerged. New discoveries show that pterosaur reproduction and growth was not comparable to that of modern avians after all, and it seems that many—perhaps most—pterosaurs were not the seabird analogues they were long held to be. Glimpses into diseases and injuries, social...

  13. 9 The Diversity of Pterosaurs
    (pp. 90-94)

    My PhD supervisor, pterosaur guru David Martill, once told me of pterosaurologists who consider all pterosaurs to basically represent the same animal, albeit with a different head and neck bolted onto each species. This really could not be further from the truth, and we’re going to spend most of the rest of this book investigating why. The proportions and anatomies of different pterosaurs are not only distinct enough that we can identify different lineages from fragmentary remains, but we can also detect a broad array of ecological strategies and locomotory methods across many groups and species (fig. 9.1).

    To appreciate...

  14. 10 Early Pterosaurs and Dimorphodontidae PTEROSAURIA > PREONDACTYLUS + DIMORPHODONTIDAE
    (pp. 95-103)

    Frustratingly little is known about the earliest phase of pterosaur evolution (fig. 10.1). Scrappy remains of the earliest pterosaur lineages are distributed across the globe (fig. 10.2; Barrett et al. 2008), with their best fossils found in Europe, North America, and more recently, Brazil. The latter occurrence is potentially rather important, as it may represent the oldest pterosaur yet found, stemming from the Carnian/Norian boundary (216 Ma) rather than, as with most Triassic pterosaurs, the upper Norian (ca. 210 Ma). NamedFaxinalipterus minima(Bonaparte et al. 2010), the fragmentary remains representing this animal bear some pterosaurian features, such as hollow...

  15. 11 Anurognathidae PTEROSAURIA > ANUROGNATHIDAE
    (pp. 104-112)

    Anurognathids, small, Muppet-faced, insect-catching pterosaurs (fig. 11.1), are one of the most intriguing, but in many ways one of the most mysterious, pterosaur groups. They are only known from a few sites around the world (fig. 11.2) and are represented by rare fossils that are often difficult to interpret. Subsequently, pterosaurologists have only recently developed a handle on their basic anatomy. It seems that anurognathids turned the bizarreness of pterosaur form up to 11, possessing a mosaic of “derived” and “basal” characteristics that has caused outright disagreements over where they fit into pterosaur phylogeny. Some authors view anurognathids as the...

  16. 12 “Campylognathoidids” PTEROSAURIA > “CAMPYLOGNATHOIDIDS”
    (pp. 113-122)

    Plenty of debate surrounds the taxonomy of various pterosaur groups, but the “campylognathoidids,” are by far the most taxonomically contentious of them all. There is virtually no agreement between modern pterosaur workers on how the species under discussion in this chapter are related to one another or other pterosaurs (see Unwin 2003; Kellner 2003; Dalla Vecchia 2003a, 2003b, 2009a, 2009b; Wang et al. 2009; Andres et al. 2010; Lü, Unwin, et al. 2010; and Lü, Unwin, et al. 2012 for different arrangements of these forms around the base of the pterosaur tree). Accordingly, I’ve had to make something of a...

  17. 13 Rhamphorhynchidae PTEROSAURIA > RHAMPHORHYNCHIDAE
    (pp. 123-134)

    Whereas the “campylognathoidids” seemed hell-bent on tweaking their anatomy at every opportunity, the rhamphorhynchid pterosaurs were a more conservative bunch that quickly organized themselves into two distinct bauplans and stuck with them for millions of years. Rhamphorhynchinae (fig. 1.1), a seagull-like lineage, seem to have been the more successful of these groups and were some of the most abundant pterosaurs of the Jurassic, enjoying 40 million years of evolution. The second lineage—the crow-like members of Scaphognathinae (fig. 13.1)—were just as widespread as their sister group, though their fossils are generally rarer and restricted to the latter 15–20...

  18. 14 Wukongopteridae PTEROSAURIA > MONOFENESTRATA > WUKONGOPTERIDAE
    (pp. 135-142)

    The twenty-first century has already furnished pterosaurologists with two of the most exciting pterosaur discoveries in living memory. The first was the recovery of pterosaur eggs (chapter 8), and the second was the discovery ofDarwinopterus, a small pterosaur from Liaoning deposits of China (fig. 14.1). This humble looking pterosaur was unveiled in 2009, but was not formally published until 2010 (Lü, Unwin, et al.) and has caused a real stir among pterosaurologists.Darwinopterusincontrovertibly fills a long-standing gap in pterosaur evolution, bridging the morphological distance between early pterosaurs and Pterodactyloidea. As we will see in subsequent chapters, pterodactyloids are...

  19. 15 Istiodactylidae PTEROSAURIA > MONOFENESTRATA > PTERODACTYLOIDEA > ORNITHOCHEIROIDEA > ISTIODACTYLIDAE
    (pp. 143-151)

    At some point in the Upper Jurassic, a lineage of wukongopterid-like pterosaurs ditched their long tails and fifth toes, thinned their bone walls, elongated their metacarpals, and became the first members of Pterodactyloidea. This major pterosaur lineage dominated pterosaur evolutionary history from the end of the Jurassic onward, replacing the preceding pterosaur lineages with new forms that existed until the close of the Cretaceous. It seems that pterodactyloids were generally larger animals and more taxomically and ecologically diverse than their predecessors, which may explain their superior fossil record. In the scheme being followed here, pterodactyloids are divided into 11 groups...

  20. 16 Ornithocheiridae PTEROSAURIA > MONOFENESTRATA > PTERODACTYLOIDEA > ORNITHOCHEIROIDEA > ORNITHOCHEIRIDAE
    (pp. 152-163)

    It seems that more pages of pterosaur literature are devoted to ornithocheirids (fig. 16.1) than any other group, a reflection of the abundance and quality of their fossil remains. The fossil record of these primarily marine, snaggle-toothed animals is expansive with 55 million years of evolution through the Cretaceous (specifically, Valanginian to Cenomanian; 140–93 Ma) and occurrences on every continent except Antarctica (fig. 16.2; Barrett et al. 2008). Much of the ornithocheirid record consists of isolated teeth and fragmentary bones, and in some localities, such remains number in the hundreds or thousands. Other ornithocheirid fossils are among the highest...

  21. 17 Boreopteridae PTEROSAURIA > MONOFENESTRATA > PTERODACTYLOIDEA > ORNITHOCHEIROIDEA > BOREOPTERIDAE
    (pp. 164-169)

    By now, I’m sure we’re all becoming accustomed to how downright strange pterosaurs look. Even species of mundane appearance have natty looking teeth and preposterous body proportions, while more extreme variants would not look out of place in a Tim Burton movie. The bizarre appearances of even these have been superseded by a newly discovered ornithocheiroid group, however, one characterized by chunky-looking headcrests, enormously stretched jaws, and incredible numbers of teeth that are so long they project well beyond the bounds of the upper and lower jaws. These animals are the boreopterids (fig. 17.1), a Cretaceous group that become known...

  22. 18 Pteranodontia PTEROSAURIA > MONOFENESTRATA > PTERODACTYLOIDEA > ORNITHOCHEIROIDEA > PTERANODONTIA
    (pp. 170-182)

    Pteranodontians are probably the most famous of all pterosaurs. Their toothless, crested forms grace films, television shows, paintings, museum halls, books, toys, and anything else with which you would want to associate a pterosaur. Fame probably found these pterosaurs because they were the first truly gigantic and spectacular flying reptiles to be discovered. The very first discoveries of pteranodontian fossils left no question that they were seriously big animals—much larger than virtually any other extinct flying creature known at that time—and they were represented by far more complete and impressive specimens than the shrapnel-like remains of large pterosaurs...

  23. 19 Ctenochasmatoidea PTEROSAURIA > MONOFENESTRATA > PTERODACTYLOIDEA > LOPHOCRATIA > CTENOCHASMATOIDEA
    (pp. 183-200)

    The ctenochasmatoids are the first of the lophocratian pterosaurs that we will meet. Comprising seven major pterodactyloid groups, Lophocratia is the more terrestrially adapted side of the pterodactyloid coin, contrasting with the strongly flight adapted ornithocheiroids we discussed in previous chapters.⁸ Two of the characteristic features of Lophocratia, their long hindlimbs and robust extremities, are obvious adaptations for a more terrestrially based existence, while the “simple” shape of their deltopectoral crests adds a further distinguishing feature (Unwin 2003). Their name—translating to “crested heads”—reflects the propensity for lophocratian pterosaurs to sport cranial crests occupying most of their skull lengths....

  24. 20 Dsungaripteroidea PTEROSAURIA > MONOFENESTRATA > PTERODACTYLOIDEA > LOPHOCRATIA > DSUNGARIPTEROIDEA
    (pp. 201-210)

    Morphologically speaking, dsungaripteroids are a country mile away from the slender, gracile pterosaurs we have met in previous chapters. With skulls and teeth that are characteristically chunky, compact necks and trunks, and reinforced limb walls, dsungaripteroids appear to represent animals adapted for a tough diet and a rough lifestyle (fig. 20.1; Fastnacht 2005b). Their remains occur in Jurassic and Cretaceous rocks from Europe, Asia, South America, and Africa (fig. 20.2), making dsungaripteroids a widespread lineage with around 40 million years of evolutionary history spanning the Kimmeridgian (155–150 Ma) to probably the Albian (112–100 Ma). There is some ambiguity...

  25. 21 Lonchodectidae PTEROSAURIA > MONOFENESTRATA > PTERODACTYLOIDEA > LOPHOCRATIA > LONCHODECTIDAE
    (pp. 211-215)

    By and large, pterosaur workers agree that that most of the major groups we are covering in this book exist in some capacity or another. As we’ve seen, their position in the pterosaur tree, composition, and nomenclatural basis may be disputed, but there is at least a general agreement that they actuallyexist. This is not the case for Lonchodectidae, animals that are championed as mysterious but important components of Cretaceous pterosaur faunas by some (fig. 21.1; Unwin 2005) but as merely a type of ornithocheiroid by others (e.g., Kellner 2003; Andres and Ji 2008; Wang et al. 2009). As...

  26. 22 Tapejaridae PTEROSAURIA > MONOFENESTRATA > PTERODACTYLOIDEA > LOPHOCRATIA > AZHDARCHOIDEA > TAPEJARIDAE
    (pp. 216-227)

    Tapejarids are relative newcomers to the world of pterosaur research. These Early Cretaceous pterodactyloids have already earned a reputation as some of the most striking pterosaurs known (fig. 22.1), largely thanks to the extreme development of their headcrests and their short, deep skulls with birdlike, downturned jaw tips. In short, they look like the devil himself fashioned them using leftover bits of cassowaries after binging on energy drinks. The first remains of tapejarids were reported by Alexander Kellner in 1989, a time in which the pterosaur community was not particularly aware of the wider group that tapejarids belong to, the...

  27. 23 Chaoyangopteridae PTEROSAURIA > MONOFENESTRATA > PTERODACTYLOIDEA > LOPHOCRATIA > AZHDARCHOIDEA > NEOAZHDARCHIA > CHAOYANGOPTERIDAE
    (pp. 228-233)

    It can be hard not to feel a little sorry for chaoyangopterid pterosaurs (fig. 23.1). Not only are they markedly unflashy compared to the other azhdarchoids (there are no spectacular wingspans or oversize headcrests here), they are often rather overlooked by pterosaur workers in discussions of azhdarchoid diversity. However, chaoyangopterids are not only an exciting and novel pterosaur group (Wang and Zhou 2002), but they spread across the globe in their short Lower Cretaceous evolutionary history (Witton 2008c) and are already represented by up to six species. Chaoyangopterids have only recently been recognized as a distinct group of azhdarchoids (Lü,...

  28. 24 Thalassodromidae PTEROSAURIA > MONOFENESTRATA > PTERODACTYLOIDEA > LOPHOCRATIA > AZHDARCHOIDEA > NEOAZHDARCHIA > THALASSODROMIDAE
    (pp. 234-243)

    Thalassodromids are among my favorite pterosaur groups, no doubt thanks to several components of my doctoral studies focusing on their taxonomy and paleobiology and, frankly, they look rather cool with their oversize skulls and backswept, bony headcrests (fig.24.1). This headgear is their most distinctive feature, substantially deepening and expanding the dorsal region of their skulls to create enormous and distinctive sail-like cranial crests. Currently, it seems that thalassodromids were a rather small group comprised of four species from a relatively tiny patch of Brazil. Despite the size of the group, thalassodromids have proved to be a highly contentious research topic...

  29. 25 Azhdarchidae PTEROSAURIA > MONOFENESTRATA > PTERODACTYLOIDEA > LOPHOCRATIA > AZHDARCHOIDEA > NEOAZHDARCHIA > AZHDARCHIDAE
    (pp. 244-258)

    It seems fitting that azhdarchids are the last group we will discuss in our tour of pterosaur diversity. Azhdarchids are perhaps the most spectacular of all pterosaurs (fig. 25.1), the sheer size and proportions of many species dwarfing not only all other pterosaurs but every other flying animal known, extinct or not. Recent investigation of their remains, recognized by pterosaurologists since the 1970s (Lawson 1975a), has revealed astounding details of their anatomy, strength, and flight capability. Many azhdarchids were as tall as giraffes and may have had the longest skulls of any nonmarine tetrapod, but they probably weighed no more...

  30. 26 The Rise and Fall of the Pterosaur Empire
    (pp. 259-264)

    The preceding chapters have hopefully made a case for pterosaurs as diverse, successful animals that are as far away from their stereotype of Mesozoic gargoyles as could be imagined. But an obvious question remains unanswered: If they were so successful, why are they extinct? Like the nonavian dinosaurs, pterosaurs persisted until the very end of the Cretaceous (Buffetaut et al. 1996), suggesting the last of their number died in the catastrophic Cretaceous/Tertiary (or “KT”) extinction event which wiped out 75 percent of all species on the planet at the end of the Mesozoic (fig.26.1). The cause of this, one of...

  31. References
    (pp. 265-282)
  32. Index
    (pp. 283-292)