Category Archives: Palaeontology

New Prothero: Twenty Five Dino Discoveries

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There is a new book by Don Prothero, and it is a new book in the microgenre of “25 things.”

The Story of the Dinosaurs in 25 Discoveries: Amazing Fossils and the People Who Found Them by Don Prothero is available now for pre-order, and is expected to hit the shelves in mid July. It will provide excellent summer reading!

You know of Prothero because of his many books including the current classic (now in its second edition) Evolution: What the Fossils Say and Why It Matters. The “25” genera includes The Story of the Earth in 25 Rocks: Tales of Important Geological Puzzles and the People Who Solved Them, and The Story of Life in 25 Fossils: Tales of Intrepid Fossil Hunters and the Wonders of Evolution.

This book has a chapter devoted to each discovery. The nature of the discovery varies, and the definition of discovery is, necessarily and helpfully, very wide ranging. In many cases, the discovery, recovery, eventual reporting or publication, and integration of a dinosaur species is a long and drawn out process involving multiple field trips, many different characters, and a lot of action. For example, the “discovery” of spinosaurus (from Egypt) comes to us as a story involving two world wars, several expeditions, great human tragedy, and some cool dinosaur bones. Other discoveries are more about how we think about dinosaurs. This is especially true of the first few chapters, which serve to illustrate how clueless early researchers were about certain things, while being pretty smart about other things.

Chapter 6, on Eoraptor, focuses not on a specific discovery, but rather, on the question of what a dinosaur actually is, how taxonomy has changed, and on attempts to identify and define the basal dinosaur (which is not Eoraptor, but it kinda is). There are other similar orienting pauses elsewhere in the book as well.

Although the chapters vary a great deal in the range of time, space, or fossil material covered, they follow a general pattern of putting together in one place most of the pertinent facts about a particular episode in the history of dinosaur research, and the pertinent facts about a particular part of the overall dinosaur bestiary. All in all, there is a good bit of history, history of the science, anatomy, evolutionary biology, scientific drama, greatness and tragedy of the act of discovory (or loss), and many many bones.

It is important for you to know that Prothero brings the reader up to date on many, probably most, of the current dinosaur controversies and conundra. The Story of the Dinosaurs in 25 Discoveries: Amazing Fossils and the People Who Found Them is divided into four sections. The first is about early finds and early thinking, from the dark ages of dinosaur research. The second focuses on the long-necked giants, the third on theropods, and the fourth on the ornithischians (duck beaked, horned, and spiky armored dinosaurs). I’ve put a current draft of the TOC at the bottom of the post to give you an idea of the detail of coverage.

I highly recommend this book.

Also by Prothero: When Humans Nearly Vanished: The Catastrophic Explosion of the Toba Volcano, Reality Check: How Science Deniers Threaten Our Future, UFOs, Chemtrails, and Aliens: What Science Says, The Princeton Field Guide to Prehistoric Mammals (Princeton Field Guides), California’s Amazing Geology, and coming out in the future: Fantastic Fossils: A Guide to Finding and Identifying Prehistoric Life, and a bunch of other books.

Part I. In the Beginning
1. Megalosaurus: The “Great Lizard,” the “Scrotum Humanum”, and the First Named Dinosaur
2. Iguanodon: Gideon Mantell, Louis Dollo, and the First Dinosaur Fauna
3. Cetiosaurus: The “Whale Lizard,” Richard Owen, and the First Known Sauropod
4. Hadrosaurus: Joseph Leidy and the First American Dinosaur
5. Eoraptor: The First Dinosaurs
Part II. The Long-Necked Giants
6. Plateosaurus: Ancestors of the Giants
7. Apatosaurus and Brontosaurus: Marsh, Cope, and the Bone Wars
8. Diplodocus: The Real “Jurassic Park” and Carnegie’s Gift
9. Giraffatitan: The Tallest of the Tall, and the Tendaguru
10. Patagotitan: Who’s the Biggest of Them All?
Part III. Red in Tooth and Claw: The Theropods
11. Coelophysis: The Little Dinosaur of Ghost Ranch
12. Cryolophosaurus: Denizen of the Polar Darkness
13. Spinosaurus: Lost Giants of Egypt
14. Tyrannosaurus: King of the Tyrant Reptiles
15. Giganotosaurus: Biggest Predator of All?
16. Deinocheirus: “Terrible Hands” Lead to Big Surprises
17. Velociraptor: “Terrible Claws” and the Dinosaur Renaissance
18. Sinosauropteryx: Feathered Dinosaurs and the Origin of Birds
Part IV. Horns and Spikes and Armor and Duck Beaks: The Ornithischians
19. Heterodontosaurus: The Origin of Ornithischians
20. Stegosaurus: The “Roofed Lizard” and the Thagomizer
21. Ankylosaurus: Armored Dinosaurs and “Mr. Bones”
22. Corythosaurus: Duckbills with Headgear
23. Stegoceras: The “Unicorn Dinosaur” and the Boneheads
24. Protoceratops: The Griffin Legend and the Origin of Horned Dinosaurs
25. Triceratops: The “Dinosaurian Bison” and the Last of the Dinosaurs

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Millipedes as long as a car, scorpions as big as a dog. A large dog.

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There are connections between the Carboniferous and our modern problem with Carbon. Some of the connections are conceptual, or object lessons, about the drastic nature of large scale climate change. Some are lessons about the carbon cycle at the largest possible scale — first you turn a double digit percentage of all life related matter into coal, then you wait a few hundred million years, then you burn all the coal and see what happens! There are also great mysteries that you all know about because every Western person and a lot of non Western people have, at one time or another, stood in front of a museum exhibit declaring, “The very spot you stand was the site of an ancient sea bla bla bla” and somewhere that exhibit, or near it, is a life size diorama with scorpions and millipedes the size of a dog. Continue reading Millipedes as long as a car, scorpions as big as a dog. A large dog.

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The latest newly discovered meteor impact that did not cause the Younger Dryas

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There is little doubt among archaeologists that the Younger Dryas, a cold snap following the initial retreat of Ice Age conditions some 11,000 years ago, had a major impact on human history. It seems that humans are highly motivated to return the impact to the Younger Dryas. Two times in recent years, evidence of an impact, a celestial object whacking into the Earth, has been suggested as the cause of the famous climatic “two step.” As sexy as impacts are, however, it is very unlikely that the Younger Dryas was caused by one. Continue reading The latest newly discovered meteor impact that did not cause the Younger Dryas

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Yet Another South American Alien Turns Out To Be Human

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But a very interesting human. A human being six inches tall (if standing), with only 12 sets of ribs, about 7 years old at the time of death. Did I mention six inches tall? New research on the so called “Atacama humanoid” (not an alien, just a human) shows a wide range of interesting genetic differences, according to a just published paper. Continue reading Yet Another South American Alien Turns Out To Be Human

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The Early Bird Crushes The Egg

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Model I birds, the kind that lived during the Age of the Other Dinosaurs, may not have brooded their eggs. Today, birds sit on their eggs in such a way that the adult bird’s down surrounds the ovoids, and warmth from the adult can keep the eggs at a constant temperature. Depending on the bird, you may find additional intersting adaptaitons. For example, Penguins use their own feet as a nest, placing the egg there. One adult broods the egg for a long period (days, in some species) and then swaps with the other adult, with the swapping being very ritualized in some cases. Like this egg swqap between parent Adelie penguins (Tip: this video does not show the actual swap): Continue reading The Early Bird Crushes The Egg

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Did humans kill off the last dinosaur?

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Classic dinosaurs went extinct long before humans existed. But birds are dinosaurs, and birds still exist. So, no.

But birds are not classic dinosaurs mainly because they are not extinct (a tautology) and they are not big and scary. But some of them were.

One of the last (but not the last) big scary bird-dinosaur creatures may have gone extinct because humans ate them, or more likely, ate their eggs. In Australia. Perhaps.

Anyway, I wrote this new finding up here, at 10,000 birds.

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Dinosaurs Biting Other Dinosaurs In The Face

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The number one rule of the Taphonomy Club is don’t talk about marks on bones … without placing them in context. Many marks on bones could have multiple causes, such as putative cut marks caused by stone tools on animal bones found on early hominid sites. In that case, hard sharp stony objects in the ground can cause marks that are hard to tell apart from stone tool marks. But when you find almost all the possible stone tool marks in the exact locations they would be if a hominid was butchering or defleshing the animal, then you can assert that that butchery or defleshing with stone tools was highly likely to have happened.

A similar logic has been applied by paleontologists DWE Hone and DH Tanke in their study of the fossil remains of a dinosaur from Dinosaur Provincial Park in Alberta, Canada. The dinosaur exhibits numerous bite marks, and apparently (unlike stone tool cut marks) identification of these marks as caused by carnivorous dinosaur teeth is not in question. But the location of the marks and other features allowed these scientists to argue that some sort of combat regularly occurred between members of members of the same species, or similar species, during the animal’s life. Given what is known about animal behavior and the kinds of dinosaurs around at the time, they claim that it is most likely combat between members of the same species.

The dinosaur in question is a juvenile Daspletosaurus. This is a genus of dinosaur extant in western North America between 77 and 74 million years ago (Late Cretaceous).

Since everyone knows all about Tyrannosaurus, it is helpful to compare Daspletosaurus to Tyrannosaurus. Daspletosaurus was smaller and older. Daspletosaurus ranged around 8 or 9 meters long and 2.5 tonnes, while Tyrannosaurus could be over 12 meters long and 10 tonnes. Tyrannosaurus also lived later (68 million years ago up to about the time of the great extinction). Both had short arms but Daspletosaurus’s arms were longer. Note that this kind of dinosaur, suborder Theropoda, gave rise to birds.

This particular juvenile Daspletosaurus was well preserved. Many of the bones are present, and their position in the matrix that bore them is not too far off from anatomical location. A good number of the missing bones may have actually eroded away after this part of the bone bed was exposed by erosion. There are marks on some of the bones that indicate post-death scavenging. But, most of the tooth marks are of the kind one would expect if a theropod dinosaur was biting it, and most interestingly, most of these marks show evidence of healing, and all but one mark indicating damage is on the head. Normally, theropod inflicted bite marks are found on various different bones of their prey. It appears that this individual was engaged in combat with other individuals of the same sort … other theropods. And, since this is probably the only theropod of this size at the time in the area, it is reasonable to conclude that this is evidence of infraspecific combat or competition.

From the study’s abstract:

Trace marks on the bones of non-avian dinosaurs may relate to feeding by large carnivores or as a result of combat. Here the cranium and mandible of a specimen of Daspletosaurus are described that show numerous premortem injuries with evidence of healing and these are inferred to relate primarily to intraspecific combat. In addition, postmortem damage to the mandible is indicative of late stage carcass consumption and the taphonomic context suggests that this was scavenging. These postmortem bites were delivered by a large bodied tyrannosaurid theropod and may have been a second Daspletosaurus, and thus this would be an additional record of tyrannosaurid cannibalism.

I contacted lead study author Dave Hone with a few questions and he was kind enough to give me answers.

I asked him if he had any guess as to the sex of this individual. While it is possible to sex some dinosaurs, he told me that this was not possible in this case.

I asked Dr. Hone to comment further on the suggestions that the most likely species to have inflicted the pre-mortum wounds was another Daspletosaurus, even though another similar dinosaur, Gorgosaurus, was around at the time. He told me, “We favour Daspleto for the premortem as we think (and based on previous papers) this is a more likely case with more intra than interspecifc aggression leading to these kinds of interactions,” similar to what we see in modern animals that exhibit this behavior. I also wondered if the size of the teeth could indicate the size of the offending beast, and thus confirm the species. He told me they did not look at this too closely because there are various problems with that approach. “We did look at the patterns of tooth distribution briefly but between different sizes of animals (juveniles vs adults) different sizes of teeth within the jaws (front vs back) and then things like missing teeth etc. there’s no way of separating them out. There’s just way too many variables and they are only leaving limited marks. It’s mostly hard to tell even very different animals apart from bite marks let alone two similar and close relatives like this.”

I asked how common Daspletosaurus is in the fossil record and if this was one of the more common tyrannosaurids. He told me that “Actually it’s not that common. The Albertan Tyrannosaurs are generally pretty common but we do for example have more Gorgosaurus and Albertosaurus than Daspleto,” though Daspletosaurus is well represented.

Daspletosaurus is distinct in part because of various extra bony bits in the face and around the eyes, which could be for any of a number of functions. I asked if it is possible that Daspletosaurus was more involved with usually-but-not-always non-lethal infraspecific combat than other tyrannosaurids, if these features are related to what might have been extra protection (or signaling features that might arise from sexual selection). If so, would this indicate something about social structure? He told me, “I’m very wary of making these kinds of extrapolations as some things that look like certain classic signals turn out not to be. My personal opinion is that these hornlets in various Tyrannosaurs likely did function in sociosexual signaling (at the very least I suspect they wouldn’t do much to protect the eyes since that would be tricky place to bite) but it’s hard to say much. Sociality is misleading here as some things can be very social and fight lots and others almost never and vice versa for solitary animals.”

I also wondered about how infraspecific combat square with the individual being relatively young. Would this imply it was fighting off adults intent on cannibalism? Or, were juveniles fighting it out like hyenas do (new born hyena males from the same litter engage in deadly combat)? Or fighting over food? Or engaged in ritual fighting behavior that precedes, as preparation/practice, adult fighting behavior? I wondered if this would say anything about life history development of behaviors in this dinosaur. Dr Hone told me that “it is really hard to say. This isn’t an adult, but then nor is it really a juvenile. We know that some dinosaurs at least can reproduce before they are fully grown (so they are sexually mature when they are not osteologically mature – actually rather like humans, though obviously rather unlike most mammals, and certainly birds). So things get complex fast. This animals was certainly old enough to have been fully independent (though of course they may or may not have been gregarious / social etc.). I doubt cannibalism was normal, I’m sure there were the odd fights that resulted in deaths or adults killed the odd small juvenile (just like crocs do) but it’s a rare behaviour to go after other big carnivores for food – they are rare and dangerous, so stick to baby herbivores. After that it gets even harder so I’d prefer not to speculate too much, though I’d guess that IF solitary, smaller individuals would probably not be holding territories, since they are not big enough to defend them, and obviously immature animals would not be competing for mates or breeding sites or IF in a group to be an alpha of some kind (though that’s not to rule out some aggression to maintain even a lower rank), but it’s not much to go on – just too many unknowns.

What we need, obviously, is some way to bring these creatures back to life so we can observe them alive!

Caption for the figure at the top of the post: Figure 1: Skull in right lateral view showing numerous injuries indicated with black arrows and the relevant code letter (see the text for details).

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The evolution of four-winged birds

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…When we look at living species (A and B) that we know shared a common ancestor resembling one of them (A), we can guess that the features seen in A evolved in steps more or less linearly to eventually resemble the corresponding features seen in B. For example, we think that chimpanzees and humans shared a common ancestor that resembled chimps a lot more than humans, and in fact, we consider living chimps to be a pretty close analog to this common ancestor. Chimp teeth are somewhat larger in relation to body size than human teeth, and human teeth have somewhat thicker enamel than chimp teeth. This might suggest that chimp-like teeth transformed over time, step by step, in a linear fashion, to become human-like … slightly smaller and somewhat thicker enameled … over evolutionary time.

That would be a reasonable hypothesis, but it would be wrong. When we look at the teeth found among fossil remains of human ancestors and their relatives, we clearly see that the creatures that arose form a chimp-like ancestor bore teeth are as different from both chimp and human teeth as one might see anywhere in the fossil record of mammals evolving over a few million years. …

Read all about it here in my latest post on 10,000 Birds.

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The seductive siren of soft tissue preservation: Ancient dinosaur flesh wasn’t ancient. Or dinosaur flesh.

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An ugly fact killing a beautiful hypothesis
I’m not mentioning any names, and don’t ask me any details. In fact, don’t repeat this story.

Some years ago, when I was a mere graduate student, a fellow student working in an unnamed country in Africa discovered a very very old stone artifact. To this day, this bit of chipped stone debris, representing the activities of an ancient very pre-human hominid, is one of the oldest well dated, in situ objects of its kind known.

The stone had some yeck on it, and for giggles, this stone got passed on to a physicist who had invented a new way of looking at small things. He was going to look at the tool to see what the yeck was. I should point out that this physicist had no knowledge to speak of of either archaeology or geology.

Right away results came back clearly indicating that the yeck was made of apatite. Apatite is, of course, the primary mineral constituent of bone. Was this a piece of ancient bone jammed into the micro-bumpy surface of an ancient stone tool?
Continue reading The seductive siren of soft tissue preservation: Ancient dinosaur flesh wasn’t ancient. Or dinosaur flesh.

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