paleontologists-from-the-united-states

"Eaton (1979) was one of the first biologists to promote the importance of among coexisting large s. In his review, he focused on interspecific interactions over carcasses and noted that larger carnivores tended to displace smaller ones from carcasses and that grouping behavior could reverse this relationship. He noted as well that interspecific battles over kills occurred and often resulted in injury or death to one of the participants. In a study of adaptations to coexistence among carnivores, Van Valkenburg (1985) pointed out the additional pressure of interspecific predation among carnivores, noting that both juveniles and adults are killed but not always eaten."

"Despite the repeated tendency of s to evolve s for hypercarnivory, a canid has yet to appear that is completely catlike, that is, without any post- s. This possible constraint on morphological evolution in canids is argued to have resulted, paradoxically, in increased flexibility over evolutionary time and a great potential for rapid diversification and clade survivorship. Finally, it is suggested that the iterative pattern of specialization of the lower molars for meat-slicing that is seen in all families of carnivores, past and present, is probably a result of intraspecific competition for food, perhaps among s. This intraspecific selective force is countered by competition among species, since there are limits on the number of hypercarnivorous species within a single community."

"The impact of , , and, to a lesser extent , on the structure of the of large is explored in one fossil and four Recent communities. Two aspects are emphasized: (1) the number of species within each guild and (2) the extent of locomotor convergence as inferred from morphology among the constituent species. Locomotor behavior reflects habitat choice, hunting mode, and escape strategy, all of which appear to be important avenues of adaptive divergence among coexisting predators."

"Talbot worked on the paleontology of both vertebrates and . Her contributions to invertebrate paleontology included a revision of the s of New York State and the investigation of Stafford limestone, also in New York State. Her discovery of the approximately eighteen-centimeter dinosaur , in the Triassic sandstone near , established her reputation in vertebrate paleontology. She postulated that this small dinosaur was a bipedal carnivore."

"Women are in many respects superior to men, since generally speaking, they have more patience and often more taste and discrimination in arranging collections and more deftness in manipulating materials. How true this is!"

"In a bowlder of which the glacier carried two or three miles, possibly, and deposited not far from the site of , the writer recently found an excellently preserved skeleton of a small dinosaur the length of whose body is about 18. The bowlder was split along the plane in which the fossil lies and part of the bones are in one half and part in the other. These bones are hollow and the whole framework is very light and delicate."

"It has been science that has greatly accelerated the human endeavor over the last few centuries and it will be science that will meet the challenges of the present century."

"“Most people think about, at most, an election cycle,” he says. That can lead to shortsightedness on issues such as climate change: “How do we, as humans with our rapidly growing populations, not destroy all the natural ecosystems?” he wonders."

"I am stubbornly optimistic and that helps me take on challenges of all sizes. During my life, I have witnessed breathtaking scientific discoveries and situations where single individuals have driven positive change. I am also a big believer in the power of teams and the ability of small groups of committed people to achieve great things."

"Once you see what science is, then there's no stopping you. If you have curiosity, if you keep your childhood curiosity, then every day is amazing."

"In prying apart the stone layers of the rocks, the scientist is, in reality, opening the leaves of the past history of our world."

"We have as much evidence that T. rex was feathered, at least during some stage of its life, as we do that australopithecines like Lucy had hair."

"If you saw a baby tyrannosaur you would probably think it was a weird looking bird. A full grown one might have had feathers too, maybe not on its whole body though, maybe more of an ornamental display sort of feathers. So traits in the theropod dinosaurs were more birdlike than say, crocodiles."

"When people look of non-avian dinosaur they’re thinking of extrapolating a cow up to that size. Mammals are much much denser than birds are, because a lot of the skeletons of sauropods (the big, long-necked ones—Apatosaurus, Brachiosaurus and the like) and theropod dinosaurs are just air. Theropods don’t have solid bones like we do; they have hollow bones. Sauropods don’t, but they have tremendous air sacs that fill up a lot of their bodies. And thus they weigh way less than a mammal scaled up to that size."

"The more that we learn about these animals the more we find that there is basically no difference between birds and their closely related dinosaur ancestors like velociraptor. Both have wishbones, brooded their nests, possess hollow bones, and were covered in feathers. If animals like velociraptor were alive today our first impression would be that they were just very unusual looking birds."

"Really the best way to understand anything about dinosaurs is by looking at living animals. You look at birds and then look at the closest living ancestor of birds, which is the crocodile. If you look at characteristics that birds and crocodiles have in common, the explanation is that the trait was in the common ancestor that birds and crocodiles had at one time."

"A couple things that we do know about theropods—the ones that most closely related to birds—is that they brooded their nests. If you go deeper in the tree, what you see is that for sauropods, we have no direct evidence that they returned to the nest after the eggs were laid. Most of the evidence for that comes from an excavation in Argentina called Auca Mahuevo. What’s thought with sauropods is that they’d just lay a bunch of eggs and leave them alone—the turtle model. Few of those would ever reach adulthood."

"If you look at crocodiles today, they aren’t really representative of what the lineage of crocodiles look like. Crocodiles are represented by about 23 species, plus or minus a couple. Along that lineage the more primitive members weren’t aquatic. A lot of them were bipedal, a lot of them looked like little dinosaurs. Some were armored, others had no teeth. They were all fully terrestrial. So this is just the last vestige of that radiation that we’re seeing. And the ancestor of both dinosaurs and crocodiles would have, to the untrained eye, looked much more like a dinosaur."

"Zoos mislead their visitors by the way the species are housed. Birds are in the Bird House, of course, and crocodiles are always segregated to the Reptile House with the other naked-skinned, scale-covered brutes. So the average visitor leaves the zoo firmly persuaded that crocodilians are reptiles while birds are an entirely different group defined by "unreptilian" characteristics - feathers and flight. But a turkey's body and a croc's body laid out on a lab bench would present startling evidence of how wrong the zoos are once the two stomachs were cut into. The anatomy of their gizzards is strong evidence that crocodilians and birds are closely related and should be housed together in zoological classification, if not in zoo buildings."

"Our own mammalian order, the primates, prides itself on hand-eye coordination, monkeys, apes, and man are all good manipulators. But no mammal can rival the chameleon for eye-tongue coordination."

"Both birds and crocs have the identical plan to their specialized gizzard apparatus, and this type of internal food processor is absent in the other "reptiles" - lizards, snakes, and turtles."

"Dinosaurs are not lizards, and vice versa. Lizards are scaley reptiles of an ancient bloodline. The oldest lizards antedate the earliest dinosaurs by a full thirty million years. A few large lizards, such as the man-eating Komodo dragon, have been called "relicts of the dinosaur age", but this phrase is historically incorrect. No lizard ever evolved the birdlike characteristics peculiar to each and every dinosaur. A big lizard never resembled a small dinosaur except for a few inconsequential details of the teeth. Lizards never walk with the erect, long-striding gait that distinguishes the dinosaurlike ground birds today or the birdlike dinosaurs of the Mesozoic."

"The dinosaurs are not extinct. The colorful and successful diversity of the living birds is a continuing expression of basic dinosaur biology."

"When the dinosaurs fell at the end of the Cretaceous, they were not a senile, moribund group that had played out its evolutionary options. Rather they were vigorous, still diversifying into new or­ders and producing a variety of big­brained carnivores with the highest grade of intelligence yet present on land."

"Humans are proud of themselves. The guiding principle of the modern age is "Man is the measure of all things." And our bodies have excited physiologists and philosophers to a profound awe of the basic mammalian design. But the history of the dinosaurs should teach us some humility... If our fundamental mammalian mode of adaptation was superior to the dinosaurs', then history should record the meteoric rise of the mammals and the eclipse of the dinosaurs. Our own Class Mammalia did not seize the dominant position in life on land. Instead, the mammal clan was but one of many separate evolutionary families that succeeded as species only by taking refuge in small body size during the Age of Dinosaurs. As long as there were dinosaurs, a full 130 million years, remember, the warm-blooded league of furry mammals produced no species bigger than a cat."

"Twentieth-century paleontologists have fallen into the bad habit of reconstructing the dinosaurs' life functions by using crocodiles as a living model. But the earliest researchers of the nineteenth century proved beyond a doubt that the dinosaurs' powerful hind limbs must have operated like the limbs of gigantic birds."

"The total turtle count - two hundred and thirty species - doesn't seem like an irresistible horde compared to the several thousand mammals in today's global ecosystem. However, turtles have scored quite an impressive ecological triumph in one very important role, that of freshwater predator-omnivore... All through the Temperate Zone, otters delight the naturalist and the lay public. But how many other freshwater, semi-aquatic mammal predators can you name? Mink, of course. Relatives of otters on one hand, land weasels on the other, mink do hunt in streams. How many others? If you caught the excellent BBC series "Life on Earth", you saw footage of the swimming shrew, the Desman of the Pyrenees, a molelike furball that dives for aquatic worms and other freshwater small fry. Our own New England star-nosed mole goes hunting in water, using its starburst-shaped snout tip to feel out wriggling prey. Andean streams flowing through Preu are host to the fish-spearing mouse, Ichthyomys, that impales prey on its projecting front teeth. But if we go to a tropical lake or sluggish river, is it full of otters, mink, and paddling shrews? No, it is full of turtles."

"Up to eight feet long and as heavy as a lioness, the adult Komodo dragon brandishes steak-knifelike teeth - sharp, recurved blades with serrated cutting edges. Showing the same sagacity found in veteran Nile crocodiles, fully adult dragons know their hunting territory from years of experience. They know where to lie along hilly game trails, awaiting the light footsteps of a deer. Attacks are instant successes or failures because the ora has no stamina, and if it misses on the first short rush, it has little sustained speed for a long pursuit. When an attack succeeds, the cruel rows of slashing teeth cut fearful wounds on the rump and thigh of ambushed animals and the stricken prey may die of massive infection days later even if it manages to break free from the dragon's mouth. Tethered livestock suffer truly terrible cuts across the legs when an ora slinks into the compound under cover of the warm Indonesian nights. Several humans, both native and European visitors, have died in savage daylight attacks. The victims simply had no warning sign that the ora was waiting patiently a few feet from the trail's edge."

"Giant predator lizards can't evolve in the presence of big mammal predators. So the lesson is that mammals suppress much of the evolutionary potential of modern lizards. Is the Komodo dragon a good working model of how dinosaurs succeeded? Absolutely not. Dinosaurs suppressed the evolutionary potential of mammals, not the other way around. And dinosaurs carried out this supression everywhere, on all the continents, not merely on a few tiny tropical isles. Dinosaurs succeeded where Komodo dragons fail."

"The message from the tropics is unambiguous: To be a successful big land animal, you must cope with mammals, and to cope with mammals you must be a mammal yourself, or at least have metabolism as high as a mammal's. And big mammals have suppressed big reptiles in our tropics for the last sixty-five million years. So how can the dinosaurs' success over mammals' be explained? By assuming that dinosaurs had low-energy metabolic styles? Not very likely."

"If we measured success by longevity, then dinosaurs must rank as the number one success story in the history of land life. Not only did dinosaurs exercise an airtight monopoly as large land animals, they kept their commanding position for an extraordinary span of time - 130 million years. Our own human species is no more than a hundred thousand years old. And our own zoological class, the Mammalia, the clan of warm-blooded furry creatures, has ruled the land ecosystem for only seventy million years. True, the dinosaurs are extinct, but we ought to be careful in judging them inferior to our own kind. Who can say that the human system will last another thousand years, let alone a hundred million? Who can predict that our Class Mammalia will rule for another hundred thousand millennia?"

"No one, either in the nineteenth century or the twentieth, has ever built a persuasive case proving that dinosaurs as a whole were more like reptilian crocodiles than warm-blooded birds. No one has done this because it can't be done."

"By themselves, brontosaur gizzards don't indicate how much or what these dinosaurs ate each day; other lines of evidence must be employed to explore these questions. But brontosaur gizzards and teeth together indicate what brontosaurs did not eat. They didn't eat soft, mushy vegetation. Birds that subsist entirely on soft fruits don't possess muscular gizzards and don't use hard pebbles for their gizzard linings. Soft, watery food requires only a short, simply constructed gut - with just enough contractile force to squeeze out all the juices. Brontosaur teeth, moreover, confirm the heretical idea that they ate a tough vegetable diet. If the brontosaurs dined only on soft water plants, then very little wear would be found on their teeth. But in fact the teeth of Camarasaurus, Brachiosaurus, and their kin manifest very severe wear, which could only have been produced by tough or gritty food."

"The rex bite is unique among better known dinosaurs. Instead of inflicting a long, shallow wound, rex jaws would thrust a few crowns deep into bone armor, killing a Triceratops with a single blow. We see close-linked co-evolution here, a terminal Cretaceous arms race. Triceratops is the commonest horned dino of the time, the final dinosaurian Age, the Lancian. T’tops departs from the ceratopsian tradition of frill construction. Torosaurus, very rare during the Lancian Age of the Cretaceous, retains that basic design: the frill is composed of thin bone rods that make a frame, with huge holes in the middle. Triceratops fills in the holes with greatly thickened bone. Why would Triceratops invest in five times as much bone volume in its frill? Well…to me the answer is obvious. Because the commonest predator has evolved great, armor-penetrating teeth. The argument goes in the other direction – T. rex evolved swollen, tall tooth crowns to deal with the unusual protection of the commonest horned herbivore."

"Put a leopard and a [Deinonychus] together and the former would be in trouble."

"[Deinonychus] is usually considered a small dinosaur. But the largest individual was an eleven-foot-long animal whose head approached half a yard long, and was of male-timber-wolf mass. If alive today it would be considered a big predator."

"To a fair extent the Tyrannosaurus species are the tyrannosaur's of tyrannosaurs; they have taken to an extreme the development of skull size, strength, and power. This and the larger, more forward-pointing mid-upper jaw teeth suggest a more potent wounding ability than the albertosaur's. The stoutness of Tyrannosaurus relative to albertosaurs is readily apparent in the skeletal restorations. They are not as graceful, but they have a well-proportioned, majestic attractiveness of their own."

"The classical view of dinosaurs presents a perplexing problem. The group of vertebrates which dominated the land before the rise of the dinosaurs were the synapsids, the mammal-like reptiles... Most paleontologists have believed that the locomotion and physiology of these mammal-like synapsids were more similar to those of active, warm-blooded mammals than to sluggish modern lizards or alligators. Surprisingly, though, when the first dinosaurs and their near relatives appeared in the Triassic period, the synapsids began to decline and soon became extinct. The dinosaurs then ruled the land unchallenged for over 100 million years while the early mammals, the surviving descendants of the synapsids, remained very small in size and number. Only after the dinosaurs suddenly disappeared about 70 million years ago did the mammals develop into the great variety of dominant land vertebrates we have today. The problem is this: if the later synapsids were such splendidly advanced animals with the improved physiology of mammals, and if dinosaurs were slow and sluggish, why were the mammal-like synapsids exterminated in competition with the first dinosaurs? And why didn't the mammals achieve a more significant diversification during the dinosaurs' reign?"

"What gave archosaurs the edge as large predators at this time, and therapsids the edge as smaller ones? Frankly, I am not sure. Both seem to have had heightened metabolic rates and fur or feather insulation... Perhaps the chief advantage enjoyed by thecodonts centered around their big, slashing attack jaws. These may have made them better big-game hunters, while the more precise cutting teeth of therapsids were more suitable for smaller prey."

"This is the theropod. Indeed, excepting perhaps Brontosaurus, this is the public's favourite dinosaur, having fought King Kong for the forced favor of Fay Wray and smashed Tokyo (with inferior special effects) in the guise of Godzilla."

"By the Cretaceous crocodilians of essentially modern form were the theropods [sic] main competitors. Yet crocodilians appear to be less abundant in most Mesozoic deposits than they are later in the mammal-dominated Cenozoic. Not only that, but they tended to be small-bodied: few specimens were as big as American alligators or Nile crocodiles. It is possible that theropods were eating the crocs. Even today, big cats once in a while kill a fairly large crocodilian. A tyrannosaur could have swallowed one whole, and gone into the water after them. Constant attacks could have suppressed croc populations, and favored the smaller, harder to catch species."

"When one reads about Tyrannosaurus and Brontosaurus, one is not dealing with species, like lions or African elephants. Instead, these are genera, a group of animal species. For example, the lion is in the genus Panthera. Species of Panthera include the lion Panthera leo, the tiger P. tigris, and the leopard P. pardus, among others. So saying Tyrannosaurus is much like saying "the big cats"."

"Ceratosaurus is and has been my favorite dino since 1958. This is a minority taste. I’ve met only one dino-digger who rated it #1 in desirability."

"[Velociraptors] are among my very favourite dinosaurs. Their long upcurved skulls, slender yet compact proportions, and great sickle claws make these elegant, attractive, yet demonic animals. There is nothing else like them. Pound for pound, these are among the most powerful of known predators; certainly no other theropod had such a combination of foot, hand, and head weaponry... Among theropods only Tyrannosaurus, with its extreme skull strength, equalled Velociraptor in total power relative to weight."

"Most experts have assumed that the allosaurs, about 35 feet long, were the worst threats to the herbivores of the Jurassic, some of which were gigantic and probably able to fend off even an allosaur. But epanterias would have spelled trouble for everyone."

"Even 'Jurassic Park III' tried to jump on the avian-dino bandwagon by making a brave attempt to adorn Velociraptor with a feathery hair-piece. (The result looked like a roadrunner's toupee- don't blame the effects-artists; it's notoriously difficult to render feathers in computer graphics animation, so we'll have to wait for 'JP IV' for a more thoroughly rendered avian pelage.)"

"Dinosaurs have a bad public image as symbols of obsolescence and hulking in­ inefficiency; in political cartoons they are know-nothing conservatives that plod through miasmic swamps to inevitable extinction."

"One might expect that mammals would have taken over the land verte­brate communities immediately, but they did not. From their appearance in the Triassic until the end of the Creta­ceous, a span of 140 million years, mam­mals remained smal and inconspicuous while all the ecological roles of large ter­restrial herbivores and carnivores were monopolized by dinosaurs; mammals did not begin to radiate and produce large species until after the dinosaurs had al­ready become extinct at the end of the Cretaceous. One is forced to conclude that dinosaurs were competitively su­perior to mammals as large land vertebrates. And that would be baffling if dinosaurs were "cold-blooded." Perhaps they were not."

"I do not be­lieve birds deserve to be put in a taxo­nomic class separate from dinosaurs."

"The culmination of tyrannosaur evolution, T. rex was one of the very last North American dinosaurs. Nothing else combined its size, speed, and power. Since its demise we have had to make do with lions and tigers and bears, and other "little" mammalian carnivores."