Pterosaurs: Natural History, Evolution, Anatomy

Pterosaurs, flying reptiles from the Mesozoic, have always taken a back seat to dinosaurs in terms of popular books. I own three books on pterosaurs:“The Illustrated Encyclopedia of Pterosaurs” by Peter Wellnhofer from 1991.“The Pterosaurs: From Deep Time” by David Unwin from 2005."Pterosaurs" by Mark Witton from 2013.These are all excellent books. The last is the subject of today's review. You should not confuse the Witton book "Pterosaurs" with a book from 2012 "Pterosaurs: Flying Contemporaries of the Dinosaurs," of which Witton is one of three coauthors.By the way, the first popular book on pterosaurs "Dragons of the Air" (1901) by H.E. Seeley is available as a free e-book at [...]Witton is at the School of Earth and Environmental Sciences at the University of Portsmith. He is a freelance artist as well as a paleontologist and has a blog at [...] .I will start with a little background on pterosaurs, which will make further discussions more understandable. Pterosaurs are the first vertebrates that learned powered flight. Compared to most vertebrates, pterosaurs tend to have extremely large heads and extremely small legs relative to their torsos. Many pterosaurs had a large ridge of bone above their dorsal vertebrae called the notarium, to which the scapula sometimes articulated. Bird wings are made of feathers attached to their (relatively short arms). Bat wings are made from skin stretched between the body and between five elongated fingers. Pterosaur wings were made from skin stretched from the body to an enormously elongated fourth finger, which is unique among vertebrates. There are enough fossils preserving the soft tissue of pterosaur wings, which is typically a few millimeters thick, that we can tell the wings contained, starting from the ventral side, a layer of blood vessels, a layer of muscle, and a layer of semi-rigid fibers. The wings and body of pterosaurs probably had some kind of fur or protofeathers, it is hard to tell which. All pterosaurs had a unique splint-like bone at the wrist called the pteroid, probably used to change the shape of the leading edge of the wing.Despite having a very different wing structure, pterosaurs are convergent with birds on may features. They had bones with very thin walls (presumably for lightness). They had very rigidified ribcages, and there is evidence in the bones for air sacs. Presumably these features could have allowed for an efficient one-way respiration system as in birds. Their brains tended to be large and globular, like a bird’s, and not elongated like a typical reptile’s. All these point to a life as agile fliers requiring large amounts of energy. (Forget the antiquated idea of pterosaurs as gliders needing to jump off high cliffs to fly.)Classically pterosaurs are divided into two types: rhamphorhynchoids (named for Rhamphorhynchus) and pterodactyloids (named for Pterodactylus). Rhamphorhynchoids lived from the Late Triassic until the Early Cretaceous. They generally were small and had large toothed heads on a short neck. They also had long tails with a rhomboid shaped vane at the end. Pterodactyloids lived from the Middle Jurassic until the Late Cretaceous. The had large heads on long necks, but no tails. Many of them were toothless.The fact that pterosaur bones are hollow means that most fossils end up looking like “roadkill,” and the fine anatomical details, such as the shape of the joints, is usually erased.Aspects of pterosaurs that were mysteries for 100 years are not so much of a mystery since about a decade ago. There are enough well-preserved specimens (e.g. from China) that we know where the wing membrane attached to the body. We have enough pterosaur trackways that we have a good idea of how they handled themselves on land: as quadrupeds walking with their legs underneath, walking on wrist pads and the sole of the foot. There are now several known pterosaur eggs, and we know pterosaur babies probably could fly as soon as they hatched. What remains a mystery is which branch of archosaurs the pterosaurs arose from. Also we do not know a specific animal that could be the "protopterosaur" ancestor, that could perhaps climb trees and glide in the style of a flying squirrel, but not fly.Witton's "Pterosaurs" has 26 chapters, the first 8 deal with general findings on pterosaurs, their anatomy, how they flew, how they got along on the ground, how they reproduced, etc. This is very similar to what you find in Unwin's book. One interesting perspective from Witton is about the idea of "weight reduction." The classical idea is that pterosaurs acquired hollow bones and air sacs to make them lighter and more airworthy. Witton reverses this and says the idea is to take animals of a constant weight and make them larger (e.g. more surface area for flight). I'm not sure one can really distinguish the two in practice, but it is thought-provoking. Another idea presented by Witton is that the masses of pterosaurs are underestimated by most workers in the field, such that the mass per wing area is much smaller than that of living birds. If we allow for larger masses in pterosaurs, we can allow for more powerful muscles, which are needed for flight.The real uniqueness of Witton's "Pterosaurs," compared to Unwin's book, is in the15 chapters on individual pterosaur subgroups. (There is a small irony here because the taxonomy is based on Unwin's system.) Each group is presented in detail: a discussion of each genus, unique features, the probable lifestyle, etc. Literature references are included. These chapters can be a little tough to get through in spots, since they are something like a professional review article, but that makes this book useful for professionals as well as interested amateurs like us. The first thing you learn is that pterosaur group names are pretty hard to remember (Anurognathidae, Wukongopteridae, Ctenochasmotoidae, etc.) But the important thing is that if you look within each group there is a tremendous diversity: longer vs. shorter heads, teeth vs. no teeth, crests vs. crests, larger vs. smaller legs and feet, long wings vs. short, claws on the hand vs. no claws, etc. Thus, pterosaurs were probably as diverse in anatomy and lifestyle as birds are now. Witton points out that the classical division into rhamphorhynchoids and pterodactyloids might not be useful in the sense that while pterodactyloids are probably a monophyletic group, the rhamphorhynchoids are probably a collection of primitive types, that might not be closely related to each other. Also, while we are pretty sure more groups of pterosaur are not likely to be identified, we know hardly anything about some groups like the Lonchodectidae because their remains are just so fragmentary.Pterosaurs can have some really bizarre anatomy. For my money, the most bizarre snout belongs to Pterodaustro (from South America). Both its mandible and maxilla are upturned. The lower jaw has hundreds of extremely elongated teeth arranged in a comb-like formation. One can only imagine Pterodaustro using this apparatus to filter feed like a flamingo. The most bizarre crest is found in Nyctosaurus (from Kansas). The crest branches into two cylindrical spars, one pointing up and one pointing back. The crest is about three times as long as the skull and about 20% longer than the head, body, and legs combined. You look at this animal and your first thought is "No way that can be real." However, there are two specimens with the crest intact, so there is no doubt.Speaking of crests, my impression from "Pterosaurs" is that the proportion of pterosaurs with crests is higher than anyone suspected before. While the crests of many pterosaurs are bony, or partly bony, some crests consist only of soft tissue. We see more of the latter now because we have more specimens with preserved soft tissue and/or we now know to look for soft tissue in fossils with ultraviolet light. The original Pterodactylus from Solnhofen, for instance, one of the first pterosaurs known, has a soft tissue crest along its entire snout. While a number of authors have suggested crests could have some aerodynamic or thermal function, it is most likely they were for sexual display since closely related species have different crests.Pterosaurs attained a size range that birds never came close to matching. Quetzalcoatlus (from Texas) is usually depicted as the largest known pterosaur in popular books, but Quetzalcoatlus belongs to a family of extremely large pterosaurs, the Azhdarchidae. The largest known is Hazegopteryx. It probably stood as tall as a giraffe, had wingspan of about 11 meters, and had the longest skull (3 meters) of any non-marine tetrapod. It is interesting that there are many large flightless birds, but as far as we know, there are no secondarily-flightless pterosaurs, even among the largest ones.The writing style of "Pterosaurs" is pretty informal, despite the "review article" format, sometimes verging on "cuteness." I don't mean this in a bad way. I was amused by section headings such as "In the Absence of Proper Data, Speculate Wildly" and figure captions such as "Tupandactulus imperator doing his best Clint Eastwood impression on the scrubby hinterland of the Aptian Crato lagoon.""Pterosaurs" has the expected photographs of fossil specimens and some very clear diagrams, plus world maps showing where key pterosaurs fossils are found. The pictures that depict living pterosaurs are of two types: the pterosaur in a standard "takeoff" pose, such that different genera can be compared, and the pterosaur in "real life" situations, flying, fighting, eating, etc. All of the restorations are watercolors done by the author. I enjoyed them and they get the point across, but they struck me as more "artistic" than "scientific", compared to comparable illustrations by, say, John Gurche.This book is well worth reading and is available at a reasonable price.

I can't remember how many dinosaur books I owned as a kid, but it was a few. Pterosaurs were mentioned in a few of them, but always the same three varieties (pterodactyl, pteranodon, and rhamphorhynchus) and always depicted in the same manner: dull-brown and hairless, flying over a desert or a cliffy seashore.The reality of pterosaurs is much more interesting, and Witton seems to be just the guy to update us all on this new understanding: an active paleontologist AND an excellent illustrator.The pterosaurs in this book are often fully-realized creatures, and viewing the illustrations makes me nostalgic for the Mesozoic era; it must have been a thrilling time, and the Earth was just as wondrous then as it is now.That said, too much of the study of ancient creatures is bogged down in endless arguments over morphology and cladistics, and in this respect Witton is a card-carrying practitioner. For decades, paleontologists have looked at bones, examined their shapes, and then made bold proclamations about the creature the bones once belong to. Well and good, until another paleontologist comes along, studies the same bones, and draws a separate conclusion... all based on just the way the bones look. This isn't science, but an endless parlor game. And for every exciting illustration in this book comes several thousand words about how researchers can't agree how to classify these creatures based on morphology alone.So while I'm sure all of that is well done, insofar as the research is top-notch and the literature cited gives a range of opinions, the only thing I really learned is that paleontology is a very petty subject. More interesting than which arguing over families and genera (which will clearly never be settled on morphology alone) are the lateral studies that help us understand how these creatures might have lived. For instance, Witton discusses how by analyzing the likely aerodynamics of the various wing shapes we can deduce that pterosaurs likely occupied a variety of habitats, just like flying creatures today.This is not a book for young readers... unless said young reader is particularly bright. Much it is not for adult readers, either; when I decided I wasn't getting anything from all the discussions about classifications and the peculiar shape of a particular metacarpal, I began to do a lot of skimming. I do think the information is presented honestly, and no claims are made that can't be supported by the fossil record. Also, more than a few myths and preconceptions are happily debunked.So, this is a frank presentation of the current (as of 2013) state of pterosaur research, excellently illustrated. It's just that the field of "pterosaurology" is presented as a disorderly field of bickering egos, and I'm pretty sure that wasn't Witton's intent (partly because it seems he likes to bicker with the best of them).

Before reading this book I knew almost nothing about pterosaurs but now I see them for the amazing, ecologically diverse creatures they were--an experiment with vertebrate flight that produced all sorts of interesting parallels with birds. I'm a professional paleontologist, so for me the discussion of bones and taxonomy is no barrier. But like many readers, I expect, the most interesting parts of this lovely book lie in the discussions of paleoecology, the controversies in `pterosaurology' and the fuzzy, still emerging vision of an alternate world of flying animals. Witton is a good writer--witty, a bit informal, and an expert with a skill at telling a story well. For me, it is a perfect combination of wit and fact; I can gloss over the bone names and inside-controversy if I want to glean the meat of how the animals worked and what their world was like. His descriptions of these animals as living things are not particularly technical and should be accessible to an general reader. People who know something about birds will likely particularly enjoy this book. But, increasingly as I read each chapter while brushing my teeth or sitting on the pot, I have taken to absorbing it all. Indeed, I have taken to comparing this book very favorably to other works of this kind, such as Long's "The Rise of Fishes" (much more taxonomic than it should be) and similar books that survey major groups. Three cheers for Mark Witton!Witton is also a good illustrator, and has put flesh, color, and speculative reality on his pterosaurs. The book is illustrated with lots of paintings, some of which are a bit more artistic than fully informative, but which give you a sense (in an `informed-speculation' way) of what these animals were like as living things. He also has lovely photographs of the actual specimens and anatomical drawings of the skeletons and other features of each group of pterosaurs. It is handy to have the photographs in this book since they help me appreciate how scrappy a lot of the fossil material actually is. That realization, in turn, tempers one's acceptance of the fully fleshed-out paintings and skeletal drawings.Still, there is enough there (amazingly, for such delicate creatures) that we gain a sense for just how diverse and incredible pterosaurs were as a group. There were flamingo-like pterosaurs, nightjar-like pterosaurs, and albatross-like pterosaurs. There were pterosaurs with huge, likely brightly colored crests, and ones with scimitar-wings and broad-rounded wings. The emerging image is of a group with huge diversity that has explored many of the same alleyways as birds. At the same time, pterosaurs were also not just an early try at being birds, since they seem to have many unique features of their ecology. Pterosaurs went in for a huge variety of head crests--massive, elaborate affairs that provided an alternative way to impress mates compared to peacock's tails. Their mouths were crammed with baskets of teeth--a distinctly un-bird-like approach to life. Further, many pterosaurs had dinky tails that seemingly must have given them oddly unbalanced bodies considering their long necks and big heads. Just how did these animals fly without nose-diving into the ground? It is unfortunate that we have just a few scraps of them in the fossil record, but what a record it is turning out to be! Glorious diversity, most wonderful!

The readability of this beautifully illustrated work by Mark P Witton, whose 'flippant prose has been turned into something that reads like science' (his words, not mine) by a lady called Sheila Dean, is first-rate. Mr Witton certainly has a great enthusiasm for his subject which is infectious and I found this book easy to read and absorb. He does all his own illustrations which are not only superb, but also inspiringly helpful.Apparently, our knowledge of pterosaurs has developed at a rocketing rate over the past 25 years as more and more fossil remains of them have been discovered. We now know beyond all reasonable doubt that pterosaurs were covered in something after the fashion of fine hair and that they were very probably hot-blooded. This book also answers a question that has always puzzled me: why are pterosaur wing membranes attached to just the one elongated finger - the one corresponding to our little finger, in fact - and not to several fingers as in bats? The answer is because, when pterosaurs were on the ground, they moved around on all fours and needed the other fingers free to form front feet for walking on.The book contains several excellent illustrations showing clearly how they did this. Several fossilised pterosaur tracks revealing how they walked on all fours, have been discovered in various places. It used to be thought that pterosaurs would have been very clumsy when grounded, but we now know that this was not the case. Unlike pterosaurs, bats cannot walk on all fours simply because most of the fingers of their front feet are used up for supporting the wing membranes. (There is a species of bat native to New Zealand which manages to move around on the ground fairly well after a fashion, but nothing like a trotting pterosaur)Although pterosaurs were not dinosaurs, Mr Witton brings forward evidence to support the belief that they were rather more closely related to dinosaurs than previously thought. It's not yet clear whether or not the insulating down-like covering on pterosaurs was more akin to feathers or hair. We do know that some dinosaurs were covered in downy feathers and that many of them also were probably hot blooded like birds which are descended from them.The book contains chapters on every known pterosaur family beginning with the earliest known pterosaurs which originated in the late Triassic. Pterosaurs continued to develop and branch out throughout the Jurassic period, reaching their zenith by the mid-Cretaceous, after which they gradually declined becoming extinct, along with the dinosaurs, in the great cataclysm at the end of the Cretaceous . Some of the very largest pterosaurs were also the most recent from the late Cretaceous and they were the largest flying animals ever known. One later pterosaur, known as Hatzegopteryx thambema, when it was walking around on all fours with its wings folded up its sides, was nearly as tall as a giraffe and had the largest wingspan of any known pterosaur, bird or bat.This readily accessible work is well supplied with helpful map, diagrams and illustrations and you can actually see pterosaurs walking around on all fours as well as flying all over the place. Mr Witton occasionally indulges us with subtle touches of helpful humour such as the caption to the picture on page 245 depicting two walking and several flying Romanian Hatzegopteryx thambema pterosaurs above the caption: 'Realising that the next chapter is about pterosaur extinction, a flock of Maastrichtian Romanian Hatzegopteryx thambena tries to fly back to an earlier part of the book to avoid the chop.' This is a great work, which really makes you feel that you are living with pterosaurs and I love it. Buy and enjoy.

A very thorough look at our non feathered flying friends. What a wealth of information! Feels very weighty, proper science going on. You need to be able to follow a good deal of technical terminology if you don't already know it. Dorsal, posterior, caudal, proximate ... bit heavy at times. Witton starts with general overview of the pterosauria, evolution, general body plan, skeleton, flight info etc. Then a list of chapters for each of the families of pterosaurs that he reckons are warranted from the fossils. And what a list, so many species! My issue is with these chapters - they become very, very repetitive in content and by the end quite frankly were a bit of a slog. If you lifted one set of names out of a chapter and replaced it with an alternative set, even as a very keen but amateur dino and related creatures enthusiast in most instances I'd not be much the wiser apart from the obvious skull difference. The issue to be grappled with is that the remains are mostly so-so such that not an awful lot can actually be definitively said, and in fact the body plan differences between many species and genuses (plural?) are also so-so such that differences are minimal. No doubt Witton's wise hesitancy to be too definitive in his judgements springs from a career grappling with minimal and equivocal material, but the lack of punch in amidst the welter of technical detail means this is not a book for the fair weather pterosaurophile. Dinosaurs are my real passion - for me pterosaurs are the interesting walk on extras - and my enthusiasm did wane. But this is clearly an important book, and one I am very pleased to have on my bookshelf. One particularly charming aspect to the book is that it is packed with Witton's own illustrations, lovely colour works, hand done and of course informed by the most current thinking. Most refreshing and mature in an era of wall-to-wall, computer generated prehistorica. After decades immersed in dinosaurs and such like I had never read anything about the soft tissue crests apparently sported by almost all pterosaurs. This book was a revelation. It will take me some time to get used to pterodactylus with a huge semi circular crest along the top of its head, but the evidence is pretty conclusive, thanks to the forensic wonders of modern technology. In terms of writing style Witton is functional, eschewing or incapable of the wit and élan of Robert Bakker, but adopts a folksy tone that for me undermines his undoubted authority. I guess he's an American, and that's just their unfussy, democratic style. I'm afraid as an old fashioned European I want my learned authors to sound and feel like they know a lot more than I do rather than dispensing homespun commonplaces from their back porch. However Witton's illustrations have an eloquence and vivacity on an entirely elevated level and quite frankly, like the creatures to which this book is a heartfelt homage, they soar.