Probably no creatures that have lived upon this Earth have excited the imagination more than the Dinosauria. For some 150 million years they dominated ever medium to large to gigantic terrestrial vertebrate ecological niche, evolving into a wide range of forms and populating every continent.
Perhaps because they often had such bizarre forms, perhaps because they sometimes grew to such huge size, perhaps because after ruling this earth for so long they suddenly vanished, seemingly without a trace; all things add to the appeal of the dinosauria in the popular imagination.
In fact it turns out, as with so many other things, that the popular imagination is mistaken. True, many dinosaurs did have rather strange forms, but were they any stranger in appearance than, say, a giraffe or an elephant? True, many of them did grow to be quite large and even enormous size, but no dinosaur has ever rivalled even the smaller baleen whales in size. It would in fact be physiologically impossible for a land animal of more than 100 tonnes to exist (it's legs would have to be so massive they would touch, leaving no space for the body between!). So much for Godzilla and the dinosaurs of One Million Years B.C. (a laughable film better known for Rachel Welch in her animal-skin bikini) - such creatures belong to the realm of Hollywood fantasy. The majority of dinosaurs were actually medium-sized creatures, equivalent to modern medium to large mammals in size. Finally, as for dying out without a trace, this is also incorrect. One lineage of small insectivorous/carnivorous dinosaurs did survive the great Mesozoic terminal extinction and are still with us today. They're called birds.
Some ecological niches the dinosaurs didn't invade. They never established themselves in the small terrestrial vertebrate niche (this was already taken over by mammals and lizards), nor (contrary to popular belief) did any of them ever adopt a marine or aquatic mode of life. They did however take over the air with style; and so successfully that their descendents are still the most numerous and diverse of the tetrapod (land-living vertebrates) even today.
Conventionally, the dinosaurs are divided into two orders, depending on the structure of the hip bones. Those that had a reptilian-like pelvic bone were put in the Order Saurischia or "lizard-hips"; while the ones with a bird-like pelvic bone made up the Order Ornithischia or "bird-hips". (Paradoxically, it was the "lizard-hipped" and not the "bird-hipped" forms that evolved into birds). This classification is still adhered to in most (especially older) popular and academic books, but has pretty much been rejected in favour of the cladistic interpretation. My own position is that both the conventional Linnean and the Cladistic arrangements have good and bad points, and in a sense each supplements the other.
Putting together a website allows one certain indulges, one of which is to present one's own interpretation of life, the universe, and everything (which may indeed be no better and no worse than anyone else's interpretation). The following, then, is my take on Dinosaur systematics and classification. Beginning with the Linnean approach (which is now out of fashion in most biology and paleontology books and web sites, but which still has certain advantages) I would divide the Superorder (this being the most appropriate Linnean ranking) Dinosauria into four orders as given below.
The earliest proto-dinosaurs (or ancestral "Ornithodira") are a group of small early dinosaur-like archosaurs that do not fit into either the Saurischia or Ornithischia category. These creatures, previously considered Ornithosuchian thecodonts, are not even formally considered dinosaurs (although they could be called "dinosauromorphs", which means dinosaurs and a few related ancestral forms). But they are the stem forms from which the others all evolved. It has also for some years been suggested that they are ancestral to the Pterodactyls (flying reptiles), in which case one could follow Dr Bob Bakker in including the Pterosaurs under the Dinosauria (as a fifth linnean order). There is however a rival and equally persuasive theory which derives the pterosaurs from Prolacertiform "lizards" (archosauromorphs). This latter theory is favoured by David Peters in the (no longre on-line) Pterosaur Home Page.
The Saurischia or "lizard hipped" dinosaurs are conventionally divided in turn into two groups, one carnivorous, the other herbivorous. The first of these are the Theropoda, the bipedal carnivorous dinosaurs, with their bird-like legs and necks. Theropoda means "beast-feet", a rather inappropriate name; "bird(-like) feet" would have been better. Included in this huge and diverse group are both small forms (among them the ancestors of birds) and large predators such as Allosaurus and Tyrannosaurus. The Theropoda are such a diverse group of animals they should really be considered an order rather than a suborder (in the Linnean hierarchy)
The other group of Saurischia, the Sauropodamorpha, are the herbivores. There are two main subgroups, the Sauropoda (the inappropriately named "lizard-feet"), and their ancestors, the Prosauropoda ("before the sauropods". Although the primitive Prosauropods were relatively small, the more advanced types, and especially all of the Sauropods, were elephantine giants with tiny heads, very long necks and tails, massive bodies, and pillar-like legs. This group includes the famous Brontosaurus (or Apatasaurus) and its relatives. Like modern-day elephants, they relied on their great size as a defense against carnivores.
The Ornithischia ("bird hipped" dinosaurs), or Predentata (so called beacuse they posses a unique extra bone in front of the jaw, which served as a sort of beak) were a more diverse group of herbivores. Being much smaller than the sauropods, they had to evolve various other means to protect themselves against their meat-eating theropod contemporaries. The inoffensive Ornithopods depended on fleetness of foot and acute sight and hearing. The Ceratopsian dinosaurs (Triceratops, etc) were the rhinoceroses of the dinosaur world, their formidable horns ample protection against even the largest and fiercest carnivores. And the Stegosaurs and Ankylosaurs evolved armour plates, spikes, and tail-clubs as defensive and offensive weapons.
The Ornithischia - unlike Saurischian dinosaurs, reptiles and birds - possessed mammalian cheek- muscles and -pouches to aid in the chewing. In this respect they paralleled the mammalian form. Certainly, many ornithischia filled similar ecological roles to mammalian ungulates.
So we see among the dinosaurs the tendency towards both an avimorphisation or bird-form-tendency in the Theropods, and a theromorphisation or mammal-form-tendency) in the Ornithischia. The dinosaurs of the Mesozoic era in a sense presaged the birds and mammals of the Cenozoic era.
(Lizard Hipped dinosaurs)
A word now about birds.
Many palaeontologists and dino-enthusiasts nowadays also consider the Birds to be a subgroup of dinosaurs. Cladistically (phylogenetically) speaking this is correct: birds evolved from dinosaurs, so if dinosaurs are to retain their monophyletic status (which is necessarily if they are to remain a valid taxon in the eyes of the cladists) they have to include Birds.
There is no denying birds are indeed very dinosaur-like in many ways. My own feeling is that Birds have the same relationship to Dinosaurs as mammals have to Therapsids (mammal-like reptiles). One option might be to consider the Birds as a superorder of Archosaurs alongside the paraphyletic Superorder Dinosauria. Birds thus constitute the culmination of Sauropsid evolution, just as mammals constitute the culmination of Theropsid evolution.
|Books, DVDs and Web Links|
Dinosaurs seem to be the most popular form of prehistoric creature on the Web. Here are some of the better dino sites, grouped according to topic.Note - this list of links is in no way intended to be definitive, or even one quater complete! But by following links from some of these links you can find more dino sites.
There are so many dinosaur sites on the web it's ridiculous. Most of them are generally orientated to kids, but there are still a few good ones.
The Dinosauria: Truth is Stranger than Fiction
a good overall intro, but not as much detail as some other sites
The Dinosauricon (formerly the Dinosaur Pages) by T.Mike Keesey. The mother of all dinosaur sites! Lists every known family, genus and species, gives evolutionary relationships between genera, and includes glossary, art gallery, charts, links, glossary, and "ask Mike" forum. The Dinosauricon's server was down for some months but is now back on line.
Dinosaurs! Gone, But Not Forgotten - a good non-technical introduction, with original dinosaur art. Covers all the main groups of dinosaurs
Dinosauria On-line by Jeff Poling
Including Dinosaur Omnipedia, Picture Gallery
and Jeff's JOURNAL OF DINOSAUR PALEONTOLOGY:
Articles and discussions from enthusiasts and actual paleontologists on various dinosaur topics
Thescelosaurus! Justin Tweet's Dinosaur site includes not only the obigatory cladogram and summary of each group, but also a short but very informative description of each species
The site of the excellent abc/bbc TV series that featured computer reconstructed dinosaurs. Beats Jurassic Park any day! The site has some real play clips from the series, also fact files and info about the making of each episode. Get the DVDs of the series!
Nearctica - Paleontology - Dinosaurs - Main Page - good annoitated list of links
Dinosaur Topics - a good list of links
Mesozoic Meanderings - despite the name, just on dinosaurs only but quite a good site
Nakasato Dinosaur Kingdom
Nakasato Virtual Museum
Dann's Dinosaur Reconstructions includes descriptions of a number of less well-known dinosaurs, and also Australian Mesozoic marine reptiles.
Dinosaur Illustrations - large index of links to Prehistoric Art - mostly dinosaurs but a few other prehistoric creatures here as well. The site to go to to look for quality dino art.
DINO RUSS's COLLECTION OF DINO GIF's a lot of material available on this site, mostly photos and drawings; includes some material by Greg Paul.
Douglas Henderson's Earth History Gallery - Doug Henderson is without doubt one of the greatest paleo-life artists around
Brian Franczak's Paleolife Art - really fantastic paintings! Another superb paleo artist
MICHAEL WILLIAM SKREPNICK - Dinosaur Art - only a few images here, but they are all excellent
Candi's Dino Art - really neat dino images, mostly theropods
Paleontological Illustration - Frank DeNota
Dinosaur Art and Modeling - features work by different artists
Black and White Dinosaur Clipart - it is not as good as some of the professional stuff listed above, but it is free! (public domain).
JurassIcon Park - collection of general-purpose dinosaur icons
Dinosaur Icons - a nice selection of icons by various artists
Lower to Middle Cretaceous Dinosaur Faunas of the Central Colorado Plateau. This paper was originally published in Brigham Young University Geology Studies, Volume 42, Part Two , pages 69-103.
|Books and DVDs|
|Simple||non-technical||Intermediate||Advanced||very technical||not rated|
Walking With Dinosaurs - if you haven't seen this magnificent series you are doing yourself a disservice. Makes Jurassic Park look like amateurs. -
Allosaurus - A Walking With Dinosaurs Special The life and times of Big Al
Books from least to most Technical:
The Simon and Schuster Encyclopedia of Dinosaurs and Prehistoric Creatures: A Visual Who's Who of Prehistoric Life by Douglas Palmer, Barry Cox (Editor), R. J. G. Savage, Brian Gardiner, Douglas Dixon - more
Dinosaurs by Eugene S. Gaffney, illustr. by John Dawson - a simple guide and intro to Dinosaurs. If you want more detail you need to go for one of the following books
The Horned Dinosaurs by Peter Dodson - everything you wanted to know about these amazing creatures - (not yet rated)
Dinosaurs: The Encyclopedia by Donald F. Glut - superb alphabetical listing of every known genus! Requires a little technical knowledge but that is unavoidable with a subject like this. In fact, this is an extremely readable, wonderfully comprehensive book. Make sure you get the supplements - so far one and two are available - as well.
Ultimate Dinosaur Book by David Lambert, John H. Ostrom (not yet rated)
In the Presence of Dinosaurs by John Colagrande, Larry Felder (Illustrator), Jack Horner - (not yet rated)
Encyclopedia of Dinosaurs ed. by Kevin Padian and Philip J. Currie - (not yet rated)
The Complete Dinosaur ed. by James O. Farlow, M. K. Brett-Surman, and Robert F. Walters - (not yet rated)
The Scientific American Book of Dinosaurs ed. by Gregory S Paul (not yet rated)