The genus Brontosaurus was based chiefly on the structure of the scapula and the presence of five vertebrae in the sacrum. After examining the type specimens of these genera, and making a careful study of the unusually well-preserved specimens described in this paper, the writer is convinced that the Apatosaur specimen is merely a juvenile of the form represented in the adult by the Brontosaur specimen….
—ELMER RIGGS, 1903
BONE WARS
Before 1880 no one could imagine a giant, long-necked, long-tailed sauropod from the limited bones of early finds of Cetiosaurus and Pelorosaurus—so they reconstructed them as giant reptilian “whales” (see chapter 3). Yet images of Brontosaurus and other sauropods are now iconic, found on everything from kids’ toys to the Sinclair Oil logo. How did this come about? What discoveries allowed us to imagine Brontosaurus and other sauropods correctly for the first time?
The key fossils were found and described thanks to the two most important American vertebrate paleontologists of the late 1800s: Edward Drinker Cope and Othniel Charles Marsh (figure 7.1). They were similar in many ways: strong-willed, brilliant, egotistical, driven, self-centered, quarrelsome, jealous, mistrustful, and always unhappy. Cope was a scientific prodigy with a talent for anatomy, but he was also pugnacious, short-tempered, and inclined to irritate and alienate everyone who could help him. Marsh was much slower, more methodical, and more introverted—but even more jealous and paranoid than Cope. In his book The Bonehunter’s Revenge, David Rains Wallace wrote, “The patrician Edward may have considered Marsh not quite a gentleman. The academic Othniel probably regarded Cope as not quite a professional.”
Figure 7.1
(A) Edward Drinker Cope in his study, surrounded by fossils; (B) portrait of Othniel Charles Marsh late in life. ([A] Image #238372, [B] image #328401, courtesy of the American Museum of Natural History Library)
Despite their similarities, they came from very different circumstances. Cope was from a wealthy and influential Philadelphia Quaker family, which helped him land positions at the Academy of Natural Sciences and a teaching post at Haverford College. He showed his genius for anatomy and natural history at age six, drawing incredibly detailed sketches of specimens and learning all their names. Joseph Leidy himself taught Cope comparative anatomy, so Cope is in a real sense the direct successor to the founder of vertebrate paleontology in the United States. Cope used his personal wealth and influence to secure a position on the famous Hayden Survey out west, and he began his career collecting important fossils from the Rocky Mountain region.
Marsh was eight years older than Cope and came from a poor family from Lockport, New York. He had to work the family farm, but he was an avid fossil collector on the side. He never thought of making fossils his career until a local collector and retired Army officer, Col. Ezekiel Jewett, encouraged him in his studies. Eventually he was a star student at Phillips Andover Academy prep school, and then at Yale. Because he started late and was much older than his classmates, they called him “Daddy” or “Captain.” His education was only possible because his rich uncle, George Peabody, decided to support him, and then gave Yale the funds to set up the Peabody Museum of Natural History with a position for Marsh as head of the museum and Curator of Paleontology. Marsh was extremely hard-working and industrious, making the best of the incredible opportunity to build the museum and collect fossils from out west that would make it one of the world’s best natural history museums.
The two men first met in Europe during the Civil War years when both were urged to go abroad to avoid being drafted into the war. Marsh had bad eyesight and would never have been accepted in the Army, and Cope was a Quaker pacifist and could not bear arms for religious reasons. Both men received the equivalent of a Ph.D. degree by attending lectures of the best European (especially German) scholars and studying the major museum collections. In Berlin, they got along famously and actually spent several days together visiting museums. They even named some of their first new species after each other.
They met again in 1868 when Marsh visited Cope in the Haddonfield, New Jersey, marl pits, where William Parker Foulke had found and given to Leidy the first specimens of American dinosaurs (see chapter 4). After Cope left, Marsh secretly bribed the pit operators to send him all future fossils, a pattern that would continue for the rest of their careers. Their relationship deteriorated further when Cope published a reconstruction of his long-necked plesiosaur from Kansas, Elasmosaurus. Marsh pointed out that Cope had put the skull on the end of the tail, not the neck—and Leidy agreed. Cope was humiliated, and their grudges began to grow as each attacked the other in print again and again. These feuds exploded into the all-out “Bone Wars” as both men went to the Wild West to get spectacular fossils and outdo each other. In the process, they and their crews collected an incredible number of specimens and named hundreds of new species—but at the price of nearly destroying each other and paleontology as well.
Marsh was the first to go west. In 1870, he arranged the first of several annual field trips with a number of rich Yale students paying their way to help him in his excavations and prospecting. The photos of these Yale trips, with the rich young dandies dressed up as tough western gunslingers, are unintentionally hilarious (figure 7.2). Through his connections, Marsh had the U.S. Cavalry guarding them all the way, even as the Native Americans were becoming restless. Marsh mounted several expeditions like these, then gave up traveling west altogether, leaving the collecting to his paid assistants. Marsh had large collections and studied the local geology of the bone beds, so he was aware of the age of his fossils. He also cultivated good relations with the tribes who were not hostile, especially Lakota chief Red Cloud, who counseled the tribes not to go on the warpath. In 1880, when Red Cloud complained to Marsh of the poor food and conditions on the reservations, Marsh used his influence to bring Red Cloud to Washington to visit the White House and successfully lobbied for better conditions on the reservations (figure 7.3).
Figure 7.2
Famous image of Marsh (back row center, with the bushy beard) and his Yale students on their expedition to collect fossils out west in 1872. Even though they were rich young Yankee gentlemen, they had to dress and look tough for the photo—and there were real dangers from hostile warriors roaming their area at that time. (Courtesy of Wikimedia Commons)
Figure 7.3
Marsh meeting with Lakota chief Red Cloud; they befriended each other out west. Marsh later interceded on Red Cloud’s behalf in Washington to get the Lakota better treatment on the Pine Ridge Reservation after corrupt agents gave them bad food and disease-carrying blankets, or robbed them completely. (Courtesy of Wikimedia Commons)
As early as 1867, Cope had paid collectors to send him fossils from the chalk beds of western Kansas (such as Elasmosaurus on which he mounted the skull incorrectly on the tail). In 1872, Cope took his first expedition out to the Wild West attached to the Hayden Survey (but receiving no money from them). Once out west, he roamed freely without paying much heed to Hayden or his crew, and he collected wherever the fossils were rich. During the summer of 1872, all three men—Leidy, Cope, and Marsh—were in the field and often collecting in overlapping areas. Their competition drove Leidy out of field collecting altogether, which ended the supply of fossils that Hayden had originally given to him.
All three men published hasty preliminary descriptions of their fossils, especially the weird six-horned, fanged, rhino-sized mammals known as uintatheres from the middle Eocene beds of Wyoming and Utah. In the rush to beat their competitors, some of the scientific announcements were sent as telegraphs, only to be garbled by telegraph operators. Some of their descriptions were so hasty that the quickly telegraphed names were incomprehensible and could not be used. In their haste and competition, Cope, Marsh, and Leidy ended up creating dozens of names for just a few species because they never bothered to check whether their discovery was similar to what one of the others had already found. Marsh’s last Yale trip was in 1873, but Cope continued to collect most summers for several years attached to the Army Corps of Engineers. When Cope was out in the Judith River badlands of central Montana collecting in the summer of 1876, Custer and his men had just been slaughtered at the Battle of Little Bighorn. The Army warned him to get out of the territory before hostile tribes found him. Cope refused because he was having so much good luck collecting. A Quaker pacifist who didn’t believe in guns, Cope had often defused the tension when dealing with Native Americans by taking out his set of false teeth and then replacing them, which amazed them.
The critical year for the Bone Wars was 1877, which is when the story of the discovery of complete sauropods begins. Marsh got the first lead from a local schoolteacher named Arthur Lakes, an Englishman living in Morrison, Colorado. Lakes had written to Marsh, and Marsh wrote back and urged him to collect more fossils for a generous payment—and to keep his discovery secret from Cope. But before Marsh’s reply arrived, Lakes also wrote to Cope and sent him a shipment of bones. Marsh’s assistant, Benjamin Mudge, then showed up, paid Lakes, and they began to work in earnest in the Morrison quarry. Meanwhile, Lakes asked Cope to send his bones back because Marsh had just paid for them.
A local naturalist, O. W. Lucas, began finding bones further to the south, near Cañon City, Colorado. He sent these bones to Cope, who immediately secured his services for future collections. Hearing of this, Marsh sent his assistant, Samuel Wendell Williston (who later became a famous paleontologist and entomologist at University of Kansas), to set up their own quarry in Cañon City and try to lure Lucas away. Fortunately for Cope, Lucas was finding much better bones than Williston and refused to be lured over to work for Marsh. Williston then gave up on Cañon City and returned to Morrison, where their small quarry collapsed and nearly killed them. Marsh would have been out of luck in the Bone Wars were it not for another lucky discovery—and a mysterious letter.
BONE BONANZA
In March 1877, Union Pacific railroad worker William Harlow Reed was hunting pronghorns in the flats east of Medicine Bow, Wyoming, to feed railway workers in his group. He shot one and hiked up a ridge to retrieve his kill. On the way down the ridge, he noticed huge bones lying all over the ground and sticking out of the rocks.
Reed had heard the news about some eastern scientist paying good money for such huge bones. He talked to his friend, stationmaster William Edwards Carlin, about the exciting find. They both agreed that such a find might pay very well, especially as they were living on bare subsistence wages in the desolate sagebrush flats of Wyoming. So they wrote a letter to Marsh:
I write to announce to you the discovery not far from this place, of a large number of fossils, supposed to be those of the Megatherium, although there is no one here sufficient of a geologist to state for certainty. We have excavated one (1) partly, and know where there is several others that we have not, as yet, done any work upon. The formation in which they are found is that of the Tertiary Period. We are desirous of disposing of what fossils we have, and also the secret of the others. We are working men and are not able to present them as a gift, and if we can sell the secret of the fossil bed and procure work in excavating others we would like to do so. We have said nothing to any-one as yet. We measured one shoulder-blade and found it to measure four feet eight inches 4 Ft. 8 in. in length. As proof of our sincerity and trust, we will send you a few fossils, at which they cost us in time and money in unearthing. We would be pleased to hear from you, as you are well-known as an enthusiastic geologist, and a man of means, both of which we are desirous of finding—more especially the latter. Hoping to hear from you very soon, before the snows of winter set in.
They signed the letter “Harlow” and “Edwards” and also hinted darkly that someone else had people in the area looking for bones.
The mysterious letter and specimens reached Marsh at Yale, and he was excited immediately because his other collectors were having little luck in Colorado. He telegraphed Williston, who took the next train to Wyoming. When he arrived at Como Station (which consisted of a couple of shacks on the railroad siding), he was told that the mysterious Harlow and Edwards lived at a ranch out by the bluff. There were crates of bones on the floor of the station, so he knew he was in the right place. Eventually they met, and Williston gave them Marsh’s check made out to “Harlow” and “Edwards.” But they could not cash it because they had used their middle names to hide their identities.
Williston was elated when Carlin and Reed took him up to Como Bluff (figure 7.4). On November 14, he wrote to Marsh that the bones “extend for seven miles & are by the ton…. The bones are very thick, well preserved, and easy to get out.” In his next letter on November 16, he told Marsh, “Cañon City & Morrison are simply nowhere in comparison to this locality—both as regards perfection, accessibility, and quantity.” Williston urged Marsh to pay Carlin and Reed $75 each (a princely sum in those days) and to get their claim established because they feared Marsh’s rival, Cope, might be looking for a chance to poach the locality (as indeed he was).
Figure 7.4
(A) Arthur Lakes’s painting of Como Bluff, with William Harlow Reed in the foreground. (B) Lakes’s geological cross section showing the Medicine Bow anticline (where the Como Bluff quarries were exposed) and the geologic setting of the region. (Courtesy of Wikimedia Commons)
Marsh had actually passed close to those very bones and did not realize it. In 1868, he was on a field excursion, traveling via the Union Pacific railroad, and stopped at Como Station to collect tiger salamanders. Another station down the line had yielded fossils, so he had paid the stationmaster there to look for more. Up and down the line, the word was out that the rich eastern professor was paying good money for old bones, and Carlin and Reed clearly heard about it.
Marsh sent Carlin and Reed a contract, paying them $90 a month (he was paying poor hard-working Williston only $40 a month), with instructions to keep out all rival collectors. Soon they had opened Quarry 1, started crating up huge bones, and sent them east on the railway. Marsh’s collectors kept this up for 10 years, sending east a ton of bones almost every week (figure 7.5).
Figure 7.5
(A) Arthur Lakes’s painting of quarrying at Como Bluff, with William Harlow Reed in the quarry. (B) Lakes painted this scene of working in Como Bluff Quarry 12 in 1879, in a blizzard in the dead of winter, and subtitled it “The Pleasures of Science.” (Courtesy of Wikimedia Commons)
It was impossible to be so productive every week because the winters are bitterly cold and snowy in Wyoming. On November 30, Williston wrote to March, “The small saurian I have not yet sent and cannot for a few days till the snow blows off so that we can find it.” Later Williston wrote, “Inasmuch as mercury in the thermometer during the next two months seldom reached zero—upward I mean—the opening of this famous deposit was made under difficulties.” When they could work, they found other surprises. Williston wrote that the quarries “are found containing remains of numerous individuals mingled together in the most inextricable confusion, and in every conceivable position, with connected limb bones standing nearly upright, connected vertebrae describing vertical curves, etc., precisely as though in some ancient mud holes the huge monsters had become mired and died, and succeeding generations had trodden their bones down and then left their own to mingle with them.”
By the spring of 1878, the winter snows had receded, and Reed, Carlin, and Williston were back at work. A mysterious visitor who called himself “Haines” was nosing around Como, supposedly to sell groceries, but he showed unusual interest in the bones and where they came from. They suspected it might be Cope, or one of his men. By the fall of 1878, Reed called Carlin lazy. Unhappy with what his boss had said, Carlin moved out and set up his own camp (he called it “Camp Misery”) and worked a different quarry. By March 1879, Carlin had opened his own quarry, sent some of the best material to Cope, and smashed up the rest. Marsh then sent his employee, Arthur Lakes, over from the earlier, less productive excavations at Morrison, Colorado, to help out. Lakes and Reed didn’t get along well either. Reed was a raw, uncouth, man who just wanted to work fast with the pick and shovel, but Lakes, a former school teacher, insisted on stopping to make sketches of the bones in the quarry before they were removed. His watercolor sketches of the harsh field conditions capture the circumstances better than any camera could (figures 7.4 and 7.5). Lakes even pioneered the first-ever plaster of Paris jackets to protect the bones as they were being jarred by hammers and chisels. In the winter of 1879, Lakes wrote that “collecting at this season is under many difficulties. At the bottom of the narrow pit 30 feet deep into which drift snow keeps blowing, and fingers benumbed by cold from thermo between 20 and 30 below zero and snow often blowing blindingly down and covering up a bone as fast as it is unearthed” (figure 7.5B).
Other workers came and went, but Reed was a constant figure at Como Bluff, even though his pay was unpredictable and so were his supplies. Reed found most of the new quarries and the most important discoveries. Once he almost drowned in an icy creek rafting across it. Some of the time he had no wagons or pack animals, so he had to carry the bones down from the hill, often 8 kilometers (5 miles) to the station. He once dragged a 186-kilogram (400-pound) leg bone 0.8 kilometers (over half a mile) down to the tracks. After six years of hard work with no appreciation from Marsh or his crew, in 1886 he resigned to take up sheep farming and guide hunting parties. But that paid much worse, so he returned to collecting old bones, first as an independent, then for other institutions (see chapter 8). The next group of collectors Marsh hired were so incompatible that they worked in different quarries and argued (even at gunpoint) whenever they crossed paths. The last of Marsh’s Como Bluff collectors, Fred Brown, worked from 1884 to 1889; when he quit, the quarries were abandoned.
Despite these hardships, the haul from Como Bluff and its 13 quarries was amazing. Many tons of bones in an excellent state of preservation yielded 26 new species of dinosaurs as well as complete or nearly complete skeletons of others previously named. Many crocodiles, turtles, lizards, frogs and salamanders, and pterosaurs were found as well. In addition, the first-ever Mesozoic mammals from North America were found. These little animals were no bigger than shrews and had jaws with teeth the size of pinheads. I had a personal connection to these fossils when I was a graduate student. Thanks to new excavations at Quarry 9, the main mammal quarry, made by the American Museum and Yale in 1968–1970, I had the great fortune of studying Marsh’s Jurassic mammals at the American Museum in the 1970s and 1980s. One of them was a new species I named Comotherium richi. The genus was named after Como Bluffs (“Como” plus -therium, Greek for “beast”), and the species honors Dr. Thomas Rich, who led the 1968–1970 American Museum-Yale party that found it.
The quarries at Como Bluff yielded the largest and most complete dinosaur skeletons ever found up to that point. By the time all the bones reached Yale and Marsh had a chance to mount the best skeleton of Brontosaurus, the mystery of the shape of sauropod dinosaurs such as Cetiosaurus was finally solved. The huge bones that had so baffled the early collectors were in fact from creatures they could not have imagined in their wildest dreams. They were the largest land animals that ever lived, with enormous bodies, limbs like tree trunks, long slender necks with small heads and simple teeth, and long whip-like tails. By the early twentieth century, several museums had mounts of large sauropods such as Brontosaurus and Diplodocus on display (see chapter 8), and the world got to know these huge dinosaurs for the first time.
Despite its popularity, many paleontologists do not regard Brontosaurus as a valid name and haven’t since 1903. This is not just a nitpicky issue but goes to the heart of what these names signify, and how we interpret them.
The problem goes back to Marsh, of course. During the Bone Wars, Cope and Marsh hastily gave names to every slightly different specimen that came from the field, without regard to what had already been named—and without looking at the specimens that had been collected and making careful comparisons. Many were named before they were even out of their crates. This was not unusual for its time. Most paleontologists then regarded genus and species names as a kind of “stamp collecting” or “trophy hunting,” and the more names you had, the better. They are what we now call taxonomic “splitters”—every slight difference in a new fossil was justification for a new name. Much of the time, the specimens had no bones in common, so there was no way to know whether they were the same or not. This type of hyper-splitting continued into the early twentieth century as well, and most of the early paleontologists created names willy-nilly—without thinking about their specimens as anything but trophies.
Beginning in the 1930s and through the 1950s, paleontologists (led by the brilliant American Museum polymath George Gaylord Simpson) began to think of their fossils as samples of living biological populations. When compared to modern biological populations, an enormous range of variability could be encompassed in a single biological population or a single species—variations that routinely would have been named as new species by earlier scientists. Paleontologists, who had long lagged behind other sciences in using math and statistics, began to incorporate statistics in their thinking wherever possible. They measured and analyzed just how much variation could be expected of a typical population or species sample. From this point onward, paleontology (and biology) began to trend toward “lumping” species together that had once been separated based on trivial distinctions. Even today my colleagues and I, using a much richer and more comprehensive fossil record, spend a lot of time getting rid of old, unjustifiable species from a century ago that were created based on differences that have no biological meaning.
This is especially true of dinosaurs. Nearly every dinosaur name still recognized as valid was probably named more than once by different people (typically Cope and Marsh, if they both got the chance). When such problems arise, biologists are bound by the rule book: the International Code of Zoological Nomenclature. This is the standard set of rules agreed to by all scientists who deal with taxonomic names of species (living or extinct). The details of the code are intricate, but one of the key principles is priority. The first name given to a species or genus in an adequately published form is the valid name, and all later names are called “junior synonyms.” The reason for this rule of priority is stability of names and to decrease arguments over whose name is better. Which name came first is usually not in doubt, so the simple rule of “who’s on first” makes most decisions simple and noncontroversial. (There are special rules for getting around long-forgotten names that are found to have priority over a well-established name that everyone uses and has used for years.)
How does this apply to Brontosaurus? It goes back to the first specimens shipped from the Rockies in 1877. The first large sauropod fossil to arrive at Yale was a specimen with the Yale Peabody Museum catalog number YPM 1860, a partial skeleton (mostly the pelvis and some vertebrae) of a juvenile from Arthur Lakes’s Quarry 10 in Morrison, Colorado. Marsh wasted no time; within weeks of receiving it, he had published on it briefly and named it Apatosaurus ajax. Two years later he received an even larger, more complete specimen of an adult (YPM 1980) from Como Bluff Quarry 10, one of the richest of all Como Bluff localities. As Marsh (1879) pointed out, it was “the most complete of the Sauropoda ever discovered.” To this spectacular fossil, he gave then name Brontosaurus excelsus, and this is the specimen that he had mounted as the centerpiece of the Yale Peabody Museum dinosaur exhibits (as it still is today). This spectacular mount influenced Henry Fairfield Osborn of the American Museum to put up a similar mount around 1900 (based on specimens Walter Granger found just northeast of Como Bluff, in Bone Cabin Quarry), which garnered worldwide attention. Both mounts bore Marsh’s name, Brontosaurus, and so Brontosaurus dominated the public consciousness and became the name associated with nearly all sauropod dinosaurs for almost a century.
About 25 years later, Elmer Riggs of the Field Museum in Chicago was studying huge sauropods that had been collected by their crews in the Morrison Formation near Fruita, Colorado, including the first Brachiosaurus (see chapter 9). He reexamined Marsh’s specimens of Apatosaurus ajax and Brontosaurus excelsus and thought that the differences Marsh had used could not be justified. In his opinion, they were all the same genus and species, with Apatosaurus being based on a partial juvenile specimen. As Riggs wrote (see the epigraph at the beginning of the chapter), “in view of these facts the two genera may be regarded as synonymous. As the term Apatosaurus has priority, “Brontosaurus” will be regarded as a synonym.”
For most paleontologists, it was “case closed.” The name Brontosaurus was officially dead after Riggs’s 1903 paper, and only rarely did legitimate paleontologists (other than Henry Fairfield Osborn of the American Museum in New York) use the name again (no matter how popular it was in the media and the public consciousness). By the 1980s and 1990s, the copycat outdated children’s books were gradually dropping Brontosaurus in favor of Apatosaurus, and even the U.S. Postal Service got into a hot controversy in 1989 over a stamp with the name Brontosaurus on it.
That all changed in 2015 when Emanuel Tschopp, Octavio Mateus, and Roger B. J. Benson published a study of all the diplodocine sauropod dinosaurs. In that paper, they revived the name Brontosaurus and claimed that it could be distinguished from Apatosaurus. The study generated a huge media frenzy focused on the trivial issue of the resurrection of the name Brontosaurus, but it missed the main point of the article about the diversity of sauropods. As many reviewers commented, it was the most thorough study of sauropods ever done and used a wide array of anatomical evidence from more than 81 specimens. No matter what its conclusions, it was a solid piece of work.
But many paleontologists (myself included) are not so sure that this study establishes Brontosaurus as a valid name again. As I have commented in print elsewhere, in the Morrison Formation alone (Late Jurassic, mainly Colorado-Utah-Wyoming), Tschopp, Mateus, and Benson record 14 different species clustered in nine genera of diplodocines (Suuwassea, Amphicoelias, Apatosaurus, Brontosaurus, Supersaurus, Diplodocus, Kaatedocus, Barosaurus, and Galeamopus) from a single formation that covers a limited geographic area and approximately 7–11 million years of time. On top of that, there are nondiplodocid sauropods, including the huge Brachiosaurus, plus Camarasaurus, Haplocanthosaurus, and possibly several more. If their reasoning is valid, in a single quarry alone (Carnegie Quarry at Dinosaur National Monument, representing a single biological fauna and a short interval of time; see chapter 8), they claim that the distinct species Apatosaurus louisae, Brontosaurus parvus, Diplodocus carnegii, and D. hallorum, Barosaurus sp. among diplodocines, plus Camarasaurus and possibly Haplocanthosaurus all lived together. That makes at least seven or eight distinct species of huge sauropods from a single interval of time and a single place, all crowding together and sharing common resources.
Paleontologists familiar with the ecology of large land animals have pointed out that this seems like an awful lot of species to all be picking the needles off the same conifers or mowing the same ferns. Huge land animals need lots of room to roam and feed. Ecological theory and empirical data show that larger species require larger home ranges. Sauropods are the largest land animals that ever lived, and they probably required huge geographic ranges to support their needs for food. The principle of competitive exclusion suggests that no two species can compete for the same resources, and that problem is magnified for larger animals, which rarely share territory with their own competing populations let alone closely related genera and species. We know of no examples of giant land vertebrates today that exist in high diversity and compete for the same resources. Nor do prehistoric faunas show more than one or two large-bodied animal species coexisting. Even during the Ice Ages, at most one species of mammoth and one species of mastodon lived in the same area, and they had very different diets, habitats, and ecologies.
As a paleontologist who has worked with the largest land mammals, I have seen this issue close up. For years, paleontologists gave multiple names to the gigantic extinct hornless rhinoceros Paraceratherium from Asia (including Baluchitherium, Indricotherium, Tsungaritherium, and other genera, plus many different species), but ecological arguments and the high variability of specimens in a single population show that they are all one genus and species. My study of the rhinos Trigonias, Subhyracodon, and Hyracodon from the Big Badlands showed that dozens of invalid species had been named based on slight differences in the crests of their cheek teeth. When large quarry samples of a single population were analyzed, it became clear that all those subtle crest differences on which so many species were based were in fact just variation within a single population, and none of those names were valid. Matthew Mihlbachler and colleagues studied the huge rhino-like mammals known as brontotheres or titanotheres and found that when all the variation in a population is taken into account dozens of names (Titanotherium, Brontotherium, Brontops, Allops, Menops, and Menodus) are invalid and only Megacerops coloradensis is a valid name for the incredible array of different-looking specimens from the late Eocene.
Based on this reasoning, I’m concerned that all these names for similar-sized sauropods living in the same region are not justified. There is no clear evidence that they had the room or the diversity of food sources or habitats to allow so many species to live close together, all with monstrous appetites as befits their huge size. As a comparable case, Mihlbachler and colleagues found that giraffes (our only living example of a huge, long-necked tree browser) are extremely variable, with lots of differences in the horns on their head, neck vertebrae, and so on, yet they are all one genus and one species (Giraffa camelopardis) with many different geographic subspecies. Some scientists have raised these subspecies to species rank because they are genetically distinct as well. Even if there are several different species of giraffes, they live in ranges that do not overlap in Africa, so you would never find two different species in the same place as is claimed for the Morrison dinosaurs. There is another limitation to be aware of: flowering plants had not yet evolved in the Late Jurassic, so these many different huge herbivores had to subsist on slow-growing conifers, which are very low in nutrition and don’t recover quickly from heavy browsing, and possibly ferns and cycads on the ground level.
So I (and many other paleontologists) reserve judgment on the Tschopp, Mateus, and Benson study until more evidence shows clearly that such a diversity of sauropods is ecologically plausible. Until then, I use the name Brontosaurus with reservations and regard Riggs’s arguments as still binding.
WRONG-HEADED DINOSAURS
Not only was the name for this dinosaur a confusing mess, but even worse, most of the museums with mounted specimens had the wrong heads on them! The skulls of sauropods are relatively fragile and apparently are easily lost from the neck vertebrae during burial and fossilization. Nearly all the good sauropod skeletons known in the early days were headless, including Marsh’s otherwise nearly complete skeleton of Brontosaurus on display at Yale and the nearly complete American Museum specimen that became iconic for Brontosaurus. Instead, a model of a skull was constructed based on “the biggest, thickest, strongest skull bones, lower jaws and tooth crowns from three different quarries.” We now know that those skull fragments were not associated with the skeleton and, in fact, probably came from a different sauropod, Camarasaurus (one of the few dinosaur genera named by Cope that is still valid), or sometimes from Brachiosaurus. Adam Hermann, who built the reconstructed skull for the American Museum mount, admitted that it was “largely conjectural and based on that of Morosaurus” (Marsh’s invalid name for what Cope called Camarasaurus—one of the few cases where a Cope name won out over a Marsh name). A similar skull was placed on the Yale skeleton, and this short-faced version of Apatosaurus became the one that the public absorbed and believed for most of a century.
Yet there was evidence for which head actually belonged on the skeletons. In 1909, while excavating the Carnegie Museum quarry that became Dinosaur National Monument, Earl Douglass (see chapter 8) found an Apatosaurus neck with a skull very close to it. It looked nothing like Camarasaurus, but more like the long-faced Diplodocus. Douglass and Carnegie Museum director William J. Holland both accepted that it was the proper head for Apatosaurus, but the influential Osborn and others refused to accept this evidence. To them it wasn’t conclusive because it wasn’t directly attached—they were also aware that it would be a lot of work to take their wrong heads off their museum mounts! Holland responded by leaving the Carnegie Museum mounted specimen headless, hoping that a better specimen with a more conclusive head-neck connection would turn up, but it never happened while he lived. When Holland died, his successor hated the headless monster and put what turned out to be a Camarasaurus skull on it.
The problem remained unresolved for decades. In the 1970s, legendary sauropod expert Jack McIntosh (who taught theoretical physics at Wesleyan University) and Carnegie curator Dave Berman researched the issue and decided Holland and Douglass were right. Not only was the skull in question near the neck, but all the bones of Apatosaurus were very much like those of diplodocines, not camarasaurs. On October 20, 1979, with much fanfare, the Carnegie Museum finally replaced the Camarasaurus skull on their mount with the proper skull, and during the 1980s and 1990s Yale and the American Museum and other institutions eventually caught up. Their hunch was confirmed in 2011 when a specimen (now in the Cincinnati Museum) was found with the head attached to the neck: the skull was like that of Diplodocus, not Camarasaurus. At the same time, another even more complete skeleton was found in the Cactus Park Quarry in western Colorado by “Dinosaur Jim” Jensen. This specimen (nicknamed “Einstein”) is now on display at Brigham Young University, and not only does it have the diplodocine skull but a complete cast of the brain inside, which has been CAT-scanned and analyzed (hence the nickname, because it’s the brainiest sauropod we know).
Over the years, more and more specimens of apatosaurs have been found, and we have learned more and more about them. Indeed, their story is closely entwined with what we now know is their close relative, Diplodocus—the most widely displayed dinosaur in the world. That is the subject of the next chapter.
FOR FURTHER READING
Colbert, Edwin. Men and Dinosaurs: The Search in the Field and in the Laboratory. New York: Dutton, 1968.
Curry Rogers, Kristina, and Jeffrey Wilson. The Sauropods: Evolution and Biology. Berkeley: University of California Press, 2005.
Davidson, Jane Pierce. The Bone Sharp: The Life of Edward Drinker Cope. Philadelphia: Academy of Natural Sciences, 1997.
Farlow, James, and M. K. Brett-Surman, eds. The Complete Dinosaur. Bloomington: Indiana University Press, 1999.
Fastovsky, David, and David Weishampel. Dinosaurs: A Concise Natural History, 3rd ed. Cambridge: Cambridge University Press, 2016.
Hallett, Mark, and Mathew J. Wedel. The Sauropod Dinosaurs: Life in the Age of Giants. Baltimore, Md.: Johns Hopkins University Press, 2016.
Holtz, Thomas R., Jr. Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages. New York: Random House, 2011.
Howard, Robert West. The Dawnseekers: The First History of American Paleontology. New York: Harcourt Brace Jovanovich, 1975.
Jaffe, Mark. The Gilded Dinosaur: The Fossil War Between E. D. Cope and O. C. Marsh and the Rise of American Science. New York: Crown, 2000.
Klein, Nicole. Biology of the Sauropod Dinosaurs: Understanding the Life of Giants. Bloomington: Indiana University Press, 2011.
Lanham, Url. The Bone Hunters. New York: Columbia University Press, 1973.
Naish, Darren. The Great Dinosaur Discoveries. Berkeley: University of California Press, 2009.
Naish, Darren, and Paul M. Barrett. Dinosaurs: How They Lived and Evolved. Washington, D.C.: Smithsonian Books, 2016.
Osborn, Henry Fairfield. Cope, Master Naturalist: Life and Letters of Edward Drinker Cope, with a Bibliography of His Writings. Manchester, N.H.: Ayer, 1978.
Remes, Kristian, Carole T. Gee, and P. Martin Sander. Biology of the Sauropod Dinosaurs: Understanding the Life of Giants. Bloomington: Indiana University Press, 2011.
Schuchert, Charles, and Clara M. LeVene. O. C. Marsh: Pioneer in Paleontology. New Haven, Conn.: Yale University Press, 1940.
Shore, Elizabeth Noble. The Fossil Feud Between E. D. Cope and O. C. Marsh: Spying, Dirty Tricks, Plagiarism—The Exciting Story of the Famous and Bitter Rivalry Between Two of America’s Greatest Paleontologists. Hicksville, N.Y.: Exposition Press, 1974.
Spaulding, David A. E. Dinosaur Hunters: Eccentric Amateurs and Obsessed Professionals. Rocklin, Calif.: Prima, 1993.
Thomson, Keith. The Legacy of the Mastodon: The Golden Age of Fossils in America. New Haven, Conn.: Yale University Press, 2005.
Tschopp, Emanuel, Octávio Mateus, and Roger B. J. Benson. “A Specimen-Level Phylogenetic Analysis and Taxonomic Revision of Diplodocidae (Dinosauria, Sauropoda).” PeerJ 3 (2015): e857.
Upchurch, Paul, Paul M. Barrett, and Peter Dodson. “Sauropoda.” In The Dinosauria, 2nd ed., ed. David B. Weishampel, Peter Dodson, and Halszka Osmólska, 259–322. Berkeley: University of California Press, 2004.
Wallace, David Rains. The Bonehunters’ Revenge: Dinosaurs, Greed, and the Greatest Scientific Feud of the Gilded Age. New York: Houghton Mifflin, 1999.
Wilford, John Noble. The Riddle of the Dinosaur. New York: Knopf, 1985.