Pterosaurs: Natural History, Evolution, Anatomy

Pterosaurs, the first vertebrates to evolve powered flight, ruled the skies from the mid-Triassic until the end-Cretaceous. Remarkably, despite dozens of popular books on dinosaurs, Witton’s Pterosaurs, which seems poised to rule the bookshelves for a long time, is only the fourth major popular work on pterosaurs since their discovery. Much has happened in pterosaur research in recent decades, and Witton aimed to be comprehensive and up to date, so the book is large with U.S. letter–sized pages, compact font, narrow margins, occasional footnotes, and abundant journal style parenthetic citations to take the inquisitive reader to the technical literature. Witton’s writing is informal and easy to read; however, contractions from spoken language are everywhere and struck me as out of place. Two introductory chapters describe the history of discovery and interpretation of pterosaurs, their relationship to other diapsids, and their evolution of flight. Often when discussing such controversial subjects, Witton presents competing interpretations in order, ending with that which he prefers. This is simpler than covering the debate chronologically, but sometimes misrepresents things. He also seems to include everything up to a line and nothing beyond, and when discussing the evolution of flight that line comes quickly. Witton presents Wild’s hypothetical ‘Vor-Flugsaurier’ and a trees down origin, largely ignores alternatives advocated by Padian and others, and concocts his own hypothetical ancestor in a mishmash of running and hopping, arboreal leaping, and trees down schemes. I sense Witton struggling with limits, deciding what to include and what to omit. Two long chapters describe the pterosaur skeleton and soft tissues, respectively, introducing anatomical terminology used throughout the book and providing a foundation for discussions of variety and specializations in pterosaurs. Three more chapters on flight, terrestrial locomotion, and growth, reproduction, and feeding review what we know of pterosaurs as living animals. With the general introduction to pterosaurs completed, the remainder of the book examines major pterosaur groups (usually families), one group per chapter with subsections devoted to specific anatomy, locomotion, and paleoecology. These chapters contain large amounts of information, usually with a healthy dose of speculation to fill gaps in our knowledge, but Witton is careful to separate the two. Turning to this review’s ‘be careful what you wish for’ section, I criticized Wellnhofer’s Illustrated Encyclopedia of Pterosaurs for ignoring phylogeny (Bennett, 1992), so I am pleased Witton includes phylogeny. He notes that there are two main schools of thought regarding pterosaur interrelationships that descend from the major analyses of Kellner and Unwin, states that he prefers the Unwinian school, and organizes the review of pterosaur groups accordingly. This works well unless you, like me, tend to prefer the Kellnerian school, in which case the brief mentions of dissent are unsatisfactory because the reasons for dissent go unmentioned. For example, Witton discusses anurognathids as the sister group to campylognathoidids and notes that dissenters view them as sister to all other pterosaurs or to the Pterodactyloidea but does not state which characters support those views. Adding insult to injury, Witton discusses anurognathids’ short heads, short tails, short pteroid bones, and wingfinger interphalangeal joints that flexed and extended, unlike all other pterosaurs in the subsection on anatomy, but does not mention that unless anurognathids were sister to all other pterosaurs, either they broke Dollo’s law of irreversibility or other pterosaur groups evolved identical inflexible interphalangeal joints convergently. The book is illustrated with Witton’s painted life reconstructions and line-drawn skeletal reconstructions plus many drawings and photographs of specimens. The paintings’ broad brush strokes give an impressionistic feeling while showing pterosaurs as colorful and dynamic. Witton’s standard pose for skeletal reconstructions is in mid-vault as the pterosaur takes off, head and neck stretching skyward, hands aground, arms and forearms extended and thrusting backward, hind limbs trailing limply in the air. Neither walking nor flying, the pose captures a fleeting awkward moment, and I would much prefer reconstructions in dorsal flying or lateral walking poses, either of which would better facilitate comparisons. The other problem with the book’s illustration is omission. The dust jacket boasts of 200 illustrations, but often when the text highlights an interesting feature, I looked for an illustration and found none. Again, I sense a struggle with limits. The text includes several dozen typographical errors, and Moganopterus is consistently misspelled as Morganopterus. On page 182, a citation is amusingly misplaced from the end of one sentence to the next to read: “Bennett’s inferences should not be casually dismissed (Bennett, 1992). ” Whereas I agree with the sentiment, I have never been so bold as to assert it in a publication! On page 194, Witton cites “Frey and Tischlinger 2010” in reference to Cycnorhamphus, seemingly an inversion of a Tischlinger and Frey abstract, but probably meant to cite Bennett’s abstract from the same meeting instead. Despite these examples, I found very few substantive errors in the text. Most problems I have with the book will go unnoticed by most readers, and anyone who notices knows too much about pterosaurs and should go outside to get some fresh air. The book’s target demographic, i.e., anyone interested in natural history who wants to learn about pterosaurs, will find the book interesting, enjoyable, and informative when read from cover to cover. The more restricted demographic of JVP readers will also find the book enjoyable when first read and a useful resource whenever researching pterosaur literature. And pterosaur fans? they will love this book and read it over and over again and again. Highly recommended.