It was easier when I was a boy. You picked up a book with lots of pictures in it, learned a few of the tongue twisting names and made a list of your favourite dinosaurs. Tyrannosaurus rex, Pteranodon, Dimetrodon, Triceratops. The names were strange yet alluring, but with practice you could take to pronouncing them like a Brontosaurus to water. Add a bit of text and a few drawings and that was enough for good marks with a school project. But read some other books and things soon start becoming complicated. You find some aren't dinosaurs at all, that Brontosaurus is actually called Apatosaurus and some bloke thinks it didn't live in water. Then you realize you'll never remember Hisanohamasaurus and even if you do it won't much matter, because someone else states it's invalid. The more you read the less you know. Why the weird names? The names are usually derived from Latin or Greek, which were regarded as universal languages within western academia. This practice continues partly because it's traditional, but also because it's actually functional. Good names, like good book titles, should give you some insight into the subject matter and, strangely enough, a mouthful like Brachyceratops does just that, as long as you can decode it. It means 'short horned face' and was selected by a paleontologist called Gilmore in 1914. The functional aspect is that you don't need to speak English to appreciate the meaning. It translates equally well into French, Russian, Chinese or whatever language. I have a map of the world on the wall. It illustrates the habitats of various animals; the lion in Africa, the tiger in India and odd looking penguins at the Arctic. I've also got a book on paleolithic cave paintings in France. Included are pictures of horses, oxen and another strange penguin. It's the vagaries of translation that place all these penguins in the wrong hemisphere. Both the map and the book have been translated from French into German. What seems to be a penguin in French is actually ein Alk (an Auk) in German. These weird names are an effective way of safeguarding information against such vagaries. Using the same word in each language avoids misunderstandings and works to make knowledge more readily accessible. Unfortunately, you still have to work hard to be able to understand them. What was a Brachyceratops anyway? Brachyceratops was a dinosaur in North America which had a short horn on its face. It is classified as being a member of the Pachyrhinosaurini, which in turn makes it one of the Centrosaurinae, thus showing it to be related to the rest of the Ceratopsidae, and so on and so forth. These and other funny names represent the branches of the tree of life. An eighteenth century Swedish scientist, Carolus Linnaeus, is credited with the suggestion that all species should have a standardized Latin name. He and others recognised that individual species could be grouped together rationally into larger categories, genera. All grizzlies are grizzlies, but their anatomy is closer to that of other bears than it is to dogs. Dogs, however, can also be lumped together with the bears, as they have more in common with each other than with say, horses. With more groups included, we now have an order, Carnovoria. If we add the horses and others, we reach a class, Mammalia. And so it goes further until we come to the kingdom, Animalia. Linnaeus didn't view this system of classification simply as a neat book-keeping exercise. Its ramifications were both scientific and theological. That this tree of life is so ordered was held to suggest design. This was interpreted as evidence for a designer; scientifically based evidence of the existence of God. A century later Charles Darwin highlighted a different possibility; inheritance guided through natural selection. Our anatomy is dictated primarily by our parent's anatomy. This interpretation depicts the tree of life as being a family tree. The relationship of its branches show patterns of common ancestry. In general, the greater the degree of similarity different species exhibit, the more recent their common ancestor. There is no indication, however, that evolution must work at a regular speed. 150 years of further research and a huge and mounting pile of evidence indicates Darwin was broadly correct. His view is supported by the fossil record, geology, comparative anatomy, embryology, genetics and other disciplines. The Brachyceratops is a ceratopsoid, a horned dinosaur, related to animals such as Triceratops. This is not simply because both had horns. They shared a whole host of anatomical similarities, from head to foot. Some of these features are also shown by an Asian dinosaur, Psittacosaurus, even though this was a very different creature. It was a small, beaked, hornless biped, which lived earlier than any known certopsoid. It nevertheless belongs to the same infraorder, ceratopsia. Which means..., which might mean it was an ancestor of Brachyceratops. An important paleontological concept is the phrase, "or might not". The fossil record Darwin recognised his theory had an apparent weakness. If all organisms are ultimately descended from common ancestors then, at some time in the past, there must have been animals displaying what we would regard as disparate characteristics; fish-frogs, toad-turtles, turtle-doves or Lord knows what. If such links existed, where are the fossils? His solution was typically elegant. The fossil record is miserably incomplete and chaotic. The fossil record is very incomplete. Before fossils can be found they have to be formed. Most bodies do not fossilize. They get eaten. The bones fracture, weather and disintegrate. Fossilization requires a complete burial, often involving silt, mud or sand. The optimum conditions are found in coastal sea areas, just where land animals don't live. Other possibilities include rivers, lakes, sand storms and the occasional volcanic eruption. Several further factors must also be taken into account. Imagine the death of our unfortunate Brachyceratops. There it was, chewing leaves one day when, would you believe it? A volcanic eruption causes a land slide which releases a flood of water via the destruction of a lake. The poor creature is securely buried beneath sand, mud and volcanic ash. It fossilizes. The area must remain subsequently geologically stable for seventy five million years or so. There must not be so much sedimentation that the fossil bed lies too deep. And some form of erosion is required, so that the bed is reasonably exposed but again, not too much. Finally, someone has to dig at just the right spot, or walk by at exactly the right time. It's not surprising dinosaur finds are rare. Furthermore, Darwin was a gradualist. He assumed evolution to be very slow; small mutations building upon small mutations over vast stretches of time. 'The link' between A and C may be more of a blur than a B. For example, would a halfway stage between scales and feathers actually be identifiable as such? Finding links and recognizing them are two different matters. All these factors might be regarded as very convenient for Darwin's line of argument. 1859 / 1861 Darwin first published his theory in 1859. As anticipated, it was not received with universal acclaim. For many, his ideas were neither acceptable nor respectable. They challenged deeply held convictions and were all the less welcome because of their cogency. This may well explain why he never became Sir Charles. So strong, however, were his arguments, they were impossible to ignore. One opponent of Darwin's theory was the German paleontologist, Hermann von Meyer. He was occupied with describing an unusual fossil from Solnhofen, Bavaria. The publication of this work in 1861 added new fuel to the controversy. This was Archaeopteryx, (to be accurate, it was a feather). A further fossil showed it to be from a small meat eating dinosaur, (aka a bird), of the Upper Jurassic. The special qualities of the Solnhofen limestone had preserved it beautifully, more or less complete but for the head. In many respects it resembles Compsognathus, already described in 1859, which came from further east in the same formation. A later specimen spent decades labelled as Compsognathus until full preparation had revealed the complete animal. One difference between the two is particularly striking. Archaeopteryx, 'ancient wing', obviously had feathered wings. They're imprinted on the stone. And so fine is the preservation, that only one conclusion is reasonable: these are the fully developed asymmetrical flight feathers of a bird. His compatriot, Andreas Wagner, came to a surprising conclusion. "I have no hesitation in declaring it to be a reptile from the order of saurians." Of the apparent feathers: "they could also represent peculiar decorations." He sought to name the genus Griphosaurus. This is all the more surprising as his description was actually based upon a drawing, rather than the specimen itself. However, it explicitly concludes with a warning, that the fossil shouldn't be seen as evidence in support of Darwinian theory. His interpretation of an animal he'd never actually seen didn't bear up to scrutiny. Richard Owen, the leading anatomist of the day, was also no supporter of Darwin, although he didn't rule out some form of evolution. At lavish cost, he was able to procure this odd relic for the Natural History Museum in London, where it's still displayed. He classified the animal as clearly a bird. Darwin's public reaction to this find was also extraordinary. If he'd shouted a loud, "told you so", it would've been understandable. Instead, he kept quiet about Archaeopteryx. Darwin was not keen on sensationalism. Weird animals Archaeopteryx should perhaps be termed a dinobird. It's usually classified as a bird, but that's a matter of taste. It could just as well be termed a reptile as indeed, some say, could all birds. Archaeopteryx predates other known avian fossils by at least 20 million years. For that reason, and because of its mixture of characteristics, it is often called the first bird, (Urvogel). This can of course not be true. It also had a mummy and daddy. The long gap between Archie and the appearance of its next known close relative, Confuciusornis, is hardly surprising. Bird skeletons are bad candidates for fossilization. They break easily and birds don't tend to live in shallow seawater. Besides, a decade ago, the gap was three or four times longer. All subsequent known avian fossils are also more bird-like than Archaeopteryx, with one possible Upper Cretaceous exception from Madagascar, Rahonavis. This observable trend, (dino-like, less dino-like, more bird-like and bird), is fully consistent with Darwinian theory. Archaeopteryx is not the only fossil to exhibit characteristics of apparently diverse animal classes. The synapsids were dominant among land faunas of the Permian and Triassic periods. The funny word 'synapsid' refers to the number of extra holes, fenestrae, found in the skull. Anapsids, such as tortoises, have massively built skulls. Synapsids, (pelycosaurs and therapsids), have one pair of fenestrae, while diapsids, (eg. crocodiles, dinosaurs), are blessed with two pairs. These openings reduce the weight and rigidity of the skull, without compromising its strength. They also happen to provide extra space. Previously, synapsids were often called 'mammal-like reptiles', and they were assumed to be descendants of anapsids. This is no longer supported. Synapsida is the sister line of Reptilia. Nevertheless, differences between early forms were none too great. The pelycosaurs, such as Dimetrodon and Moschops, flourished and then faded into extinction during the Permian. They don't look very mammal-like. The extra spaces in their skulls did, however, enable them to develop stronger muscles for biting. This trait was inherited by the therapsids, three orders of which survived into the Triassic. One was the dicynodonts, odd herbivores, characterized generally by having only two, tusk-like teeth. Another order, the cynodonts, was complexer, and brought forth both plant and meat eaters. Some survived until the Lower Cretaceous. The Triassic cynodonts became progressively more mammal-like. Their teeth showed differentiation. The legs straightened and lengthened and their joints adapted, allowing an upright rather than sprawling gait. And animals such as Pachygenelus provide evidence of even more profound developments. The bone on the snout of a number of cynodonts features small pits, like those found on the skeleton of a cat. These hollows enable cats to use their whiskers as highly effective sensory organs, by providing room for the necessary concentration of blood cells and nerves. Whiskers are merely specialized hairs. Some cynodonts, therefore, seem to have had hair. That in turn suggests endothermy, so called 'warm-bloodedness'. The primary function of mammalian hair is insulation, not sensory perception. Endothermic, hairy 'reptiles' are surely weird animals. What made Pachygenelus a 'reptile'? Pachygenelus is more like a mammal than a 'reptile'. Several features of the skull, however, aren't mammalian enough. The jaw is composed of one large and several reduced bones and is doubly joined to the cranium on each side. One joint, (quadrate-articular), is typically reptilian, whilst the second is mammalian, (dentary-squamosal). Also, there's only one bone in each ear, (the stapes). Upper and lower molars, (although similar to those found in mammals), aren't properly aligned with each other. Such details are fairly trivial but not without significance. The mammal jaw is a single bone, the dentary. The smaller ones have taken up residence in the ears, (malleus and incus), where they enhance our sense of hearing. And let's just mention the monotremes; the duckbilled platypus and echidnas. These Australian mammals are very much alive and decidedly weird. The first (stuffed) platypus specimen to be shipped to England was assumed to be a fake. They lay eggs, which is positively 'reptilian'. Complexity through ignorance As stated, the fossil record is miserably incomplete and chaotic. This adds hugely to the appeal of paleontology. It affords so much room for speculation. For example, we know that Archaeopteryx had feathers. We also know that the Compsognathus fossil shows no such imprints. Both fossils are more or less the same age and from more or less the same place. Does that mean that Compsognathus could not have been feathered? No. It surely had scales, but there's no direct evidence of any. Valid judgements can only be made on the basis of what can be seen, not what isn't seen. Thereafter, speculation is essential because of the shortage of evidence. Mistakes are inevitable, breeding confusion. Nature does not normally provide an orderly display of fossilized skeletons, set up and labelled as in a museum. Most bones are missing and the rest may be scattered and broken. Complete and fully articulated finds are extremely rare. Dromaeosaurus is a reasonably well known dinosaur, but there's no complete example. The Mongolian genus, Hulsanpes, is based on a partial foot. Ohmdenosaurus, from Germany, is one and a half rear leg bones. Its compatriot, Elephantoides, consists of some footprints. More confusion results from multi-naming. Apatosaurus, Atlantosaurus and Brontosaurus all actually refer to the first named genus. Each was coined by Othniel Marsh between 1877-79, who was undoubtedly rather busy at the time. The poorly preserved south European nodosaur, Struthiosaurus, has been variously named about a dozen times, whilst the plateosaur species, Plateosaurus engelhardti, has had 25 or so different christenings since 1837. Whole families can be brought into disrepute. Fabrosaurs are fairly common in books and magazines. Fabrosaurus, however, consists of a partial jaw with some teeth, which is very possibly from the later discovered and named Lesothosaurus, which was originally held to be Fabrosaurus. The infraorder, ceratopsia, takes it name from an animal which became Triceratops, as Ceratops had already been used 70 years earlier to describe something completely different. And then there's the fun of misinterpretations and revisions. My favourite is Aachenosaurus. This dynamic creature was subsequently found to be a bit of fossilized wood. The Upper Cretaceous Indian 'stegosaur', Dravidosaurus, became a plesiosaur, but not until compelling theories had been devised, accounting for its remarkable survival, long after the extinction of all other stegosaurs. I'm waiting for the revision to be revised, and it probably will be. And that's largely why it's all so complicated. Source of quotations: Sitzungsberichte der Bayerischen Akademie der Wissenschaften, vol 2, Heft II (1861), pages 146 - 154, - Mr A Wagner reports on a ";new reptile, supposedly furnished with feathers." - (with thanks to Mr Chris Nedin for the translation.) Available at: http://odur.let.rug.nl/~nieuwlnd/source2.htm Further thanks are due to Mr Lenny Flank for his concise essay, "Therapsid--Mammal Transitionary Series". Available at: http://www.geocities.com/CapeCanaveral/Hangar/2437 "That article was interesting. Are there any more on-line?" I'm pleased you asked. Have a look here. Trevor Dykes, Nuremberg, October 2000, last revised April 2005 ktdykes@arcor.de Trevor Dykes was born in Bournemouth, England in 1962. He lacks expertise and knowledge across an impressively broad range of paleontological disciplines. Consequently, the accuracy of his views should not be relied upon. Specialist areas of disinterest include anatomy, chemistry and physics. His scientific qualifications are too few to list.