Info

Scientific Studies of Dinosaurs in the First Half of the Twentieth Century

The turn of the last century was a seamless transition for most dinosaur paleontologists, but the deaths of Cope in 1897 and Marsh in 1899 symbolized the beginning of the new era. As changes in modes of transportation and communication began to make the world a smaller place, the study of dinosaurs became more global, expanding to areas of the world outside Europe and the Americas. Dinosaur paleontologists also became more cooperative and engaged in friendly competition, a spirit that has, for the most part, continued to today. Last, fundamental connections between dinosaur body fossils and trace fossils were made that firmly established the dual importance and complementary nature of these facets for interpreting dinosaurs. But during the first half of the twentieth century, two world wars disrupted dinosaur studies; these wars not only resulted in a huge loss of human life

FIGURE 3.9 Franz Nopcsa, dinosaur paleontologist, Transylvanian nobleman, linguist, spy, and motorcycle enthusiast, shown here in Albanian costume and carrying optional field gear. From Kubacska, Andras Tasnade, 1945. Verlag Ungarischen Naturwisenschaftlichen Museum, Budapest/Dover Publications.

but also the destruction of dinosaur skeletons. Some skeletons were sunk during submarine attacks of World War I while being transported across the Atlantic, and other skeletons in German museums were destroyed in bombing raids by Allied forces in World War II.

Of all Europeans who worked on dinosaurs in the early part of the twentieth century, Franz (Ferenc) Baron von Felso-Szilvas Nopcsa (1877-1933) was the most likely contender for William Buckland's position as the most unusual dinosaur paleontologist (Fig. 3.9). The Transylvanian nobleman became a paleontologist by accident after his sister found some bones on her estate. He brought the bones to a university professor to identify, and the professor told him, "Study them yourself," which he did. Although Nopcsa had no prior training in paleontology, he subsequently published a description of the Cretaceous hadrosaur Telmatosaurus trans-sylvanicus in 1900. He then conducted more research on the dinosaurs of his home country, as well as those in England and France. Nopsca soon broadened his scope to include large-scale concepts such as classification schemes, evolutionary relationships of dinosaurs, and integration of the (then) new idea of continental drift with dinosaur distributions (Chapters 4 and 6). Although he was not always correct, Nopcsa's thinking was original, and he may have been the first dinosaur paleontologist to look intensively for sex differences in dinosaur species, a field of study that generated much interest later (Chapters 5 and 8).

In addition to his paleontological ambitions, Nopcsa decided, after traveling through Albania and studying its cultures and dialects, that he was the most qualified person to rule it as king. He planned to accomplish this goal through various imaginative machinations, which he shared with officials of the Austria-Hungarian government. These plans included military strategies for invading Albania and generating revenue for the new nation-state through marriage with a not-then-identified daughter of an also-not-then-identified American millionaire. He figured that it would be no problem to find one after he was crowned as a king. The government declined his offer, and he never did find his hypothetical rich wife. Instead, his life took even stranger turns:

■ He was involved in secret missions during World War I as a spy.

■ The Romanian government seized his estates.

■ He was nearly beaten to death by an angry mob of peasants.

■ He was placed in charge of the Hungarian Geological Survey.

■ He angrily quit the Survey.

■ He took off on a 5500 km long motorcycle ride with his male Albanian secretary, who was also his lover.

■ He completed impressive works on dinosaur bone histology as related to their classification.

■ He became depressed, shot his lover, and committed suicide.

On a more mundane note, the finds of western North America continued with the prodigious output of Barnum Brown in the early 1900s. In 1902, Brown discovered one of the largest (and certainly the most famous) of land carnivores, Tyrannosaurus rex, in the Late Cretaceous Hell Creek Formation of eastern Montana. Brown then followed Lambe by taking a barge down the Red Deer River in 1910, to explore Upper Cretaceous deposits there. For the next six years, Brown and his associates, working through the American Museum, directed by Osborn (who in 1905 named another tyrannosaurid, Albertosaurus, from this region: Chapter 9), collected dinosaur bones from two different geologic levels. These vertically-separated levels indicated different times in geologic history (Chapter 4), so Brown's collections contributed greatly to understanding the evolutionary sequences of dinosaurs during the Late Cretaceous. Besides tyrannosaurids, other dinosaurs documented from this area include the hadrosaur Corythosaurus (Chapter 11), some ceratopsians, such as Monoclonius, Anchiceratops, and Leptoceratops (Chapter 13), the large theropod Centrosaurus, and the ostrich-like theropod Struthiomimus (Chapter 9). In 1907, Brown was the first paleontologist to write about dinosaur gastroliths ("stomach stones") that dinosaurs probably used for grinding food in their digestive systems (Chapter 14). In his report, Brown noted that he found gravel associated with the skeleton of the hadrosaur Claosaurus, which he interpreted as gastroliths, but such hypotheses remain controversial and require much careful documentation before conditional acceptance.

The Sternbergs (Charles M. and his brothers) followed Brown's efforts. Prior to their work in Alberta, the Sternbergs made one of the most unusual and scientifically-valuable dinosaur finds of the time, when they discovered a hadrosaur in Wyoming in 1908 with skin impressions associated with the skeleton (Chapters 6). To confirm that their find was not a fluke, they later found another example nearby, which indicated similar conditions of preservation. The brothers were then employed by the Canadian Geological Survey, which was becoming tired of seeing Americans get all of the credit for dinosaurs found in Canada and then taking the Canadian dinosaurs out of the country to New York City. The Sternbergs started their work in the same Red Deer River area in 1911, using not only a barge for travel but also motorboats for occasional prospecting trips to shore. Among the Sternbergs' discoveries were specimens of the hadrosaur Prosaurolophus (Chapter 11), ankylosaurs (Chapter 12), the ceratopsians Chasmosaurus and Styracosaurus (Chapter 13), and a large theropod, Gorgosaurus, which is often viewed as synonymous with Albertosaurus (Chapter 9). The area prospected by Brown's group and the Sternbergs (constituting an example of the aforementioned friendly competition) is now known as Dinosaur Provincial Park. Within this area is Drumheller, Alberta, home of Royal Tyrrell Museum of Palaeontology, which contains some of Canada's finest dinosaur skeletons.

Far to the south of Alberta is another famous museum, one that is built around dinosaurs still in their entombing Upper Jurassic rock. Dinosaur National

FIGURE 3.10 Outcrop of Morrison Formation (Late Jurassic) with extremely abundant dinosaur bones, discovered by Earl Douglass in 1909, Dinosaur National Monument, near Jensen, Utah.

Monument, near Jensen, Utah, contains about 1500 in situ dinosaur bones, which are available for public viewing today (Fig. 3.10). This happy circumstance was prompted largely by the efforts of Earl Douglass (1862-1931). In 1909, when Douglass discovered this site (probably the most important Late Jurassic dinosaur deposit in the world), he found what turned out to be a nearly complete specimen of Apato-saurus (Chapter 10). Subsequent quarrying from 1909 to 1922, sponsored by industrialist and philanthropist Andrew Carnegie (1835-1919) for his Carnegie Museum (now the Carnegie Museum of Natural History, in Pittsburgh, Pennsylvania), yielded numerous skeletal remains of Allosaurus, Apatosaurus, Diplodocus, Dryptosaurus, and Stegosaurus. One of the more significant specimens was a juvenile Camarasaurus that was nearly complete and articulated, a very unusual find (Chapters 7 and 10). Workers at this site may have been the first to use explosives, such as dynamite (invented by Alfred Bernhard Nobel, 1833-97, of Nobel Prize fame), for extracting dinosaur skeletons from their rocky matrix, a practice that has mercifully lessened since then. Two interesting side notes are that the trivial name in Apatosaurus louisae was named after Carnegie's wife, Louise, and "Diplodocus" was the subject of the first (but certainly not last) dinosaur-themed pub song.

Similar dinosaur quarries in the western United States, which were found and mined during the first half of the twentieth century, were the Howe and Cleveland-Lloyd Quarries. The Howe Quarry was named after rancher Barker Howe, who discovered dinosaur bones on his property in northwestern Wyoming and called in Barnum Brown to investigate in 1934. Brown and his assistants then uncovered a dense accumulation of Late Jurassic bones. The extreme density is confirmed by actual data. Brown mapped meticulously in approximately 1 m2 intervals. The assemblage includes mostly sauropods, such as Apatosaurus, Barosaurus, Camarasaurus, and Diplodocus (Chapter 10). Their maps show the distribution of the bones (Fig. 3.11). Bone abundance can be calculated using the following information:

where A is area, l is length, and w is width. The area of the Howe Quarry was 14 x 20 m, hence its total area was

FIGURE 3.11 Map of Howe Quarry, showing horizontal distribution and concentration of dinosaur bones in the quarry area. Squares represent approximately meter squares. Neg. No. 314524. Courtesy Department of Library Services, American Museum of Natural History.

Bone abundance can be calculated by dividing the number of bones by the area:

where Ba is bone density in bones per square meter, N is total number of bones, and At is total area. Knowing that at least 4000 bones were recovered from this area,

Keep in mind that this number is equivalent to the mean number of bones per square meter, which does not take into account that some meter squares may not have had bones, or other squares had considerably more than 14. Additionally, looking at a bone map clearly shows how some bones transect the meter-square boundaries, leading to some restrictions about how to count bones within an area. Nevertheless, such calculations provide a measure of the relative abundance of skeletal components at a given site. Bone mapping, done at the Howe site by Brown's assistant Roland T. Bird (1899-1978), was the first attempt to record such information in this amount of detail. This method is now a standard procedure at any dinosaur bone deposit because it provides much evidence for hypotheses about the post-death history of a dinosaur assemblage. For example, an abundance of dinosaur bones probably indicates rapid burial of a number of dinosaurs together, through some unusual event such as a river flood or ash deposit (Chapter 7). The Howe Quarry also yielded dinosaur skin impressions, as well as a few dinosaur trace fossils, such as gastroliths and tracks.

The Cleveland-Lloyd Quarry, which was first uncovered near the small, eastern Utah town of Cleveland in 1937, also had a high bone density of Late Jurassic dinosaurs in a relatively small area. With the guidance of William Lee Stokes (1915-95) of Princeton University from 1937 to 1941, more than 12,000 dinosaur bones were recovered from the site, of which 60% to 70% are from Allosaurus and the rest from such dinosaurs as Camarasaurus, Stegosaurus, and the ornithopod Camptosaurus. The assemblage is unusual in its concentration of allosaur skeletons, leading to hypotheses that explain why so many meat-eaters would be in such a small area (Chapters 7 and 9). Stokes later adopted Utah as his home and spent much of his career at the University of Utah.

Roland Bird, who mapped the Howe Quarry, became more famous for his work with dinosaur tracks, particularly in eastern Texas, but also in Arizona, Colorado, and Utah. Like many early dinosaur-fossil discoverers, Bird had little formal academic training but had developed a successful search pattern for dinosaur fossils through extensive experience (Chapter 2). After finding several tracksites in Jurassic and Cretaceous rocks of some western states, he decided that these sites were too inaccessible. Subsequently, he followed up a tip and in 1939 went to Glen Rose, Texas, where he found dinosaur tracks exposed in Lower Cretaceous rocks of the Paluxy River. These tracks were made by a variety of theropods, but most importantly included undoubted sauropod tracks (some more than a meter wide), the first reported scientifically from the geologic record. One excellent paleontological point of discussion provoked by the sauropod tracks was whether they indicated that sauropods had aqueous habits (which was presumed at the time) or whether they walked on dry land (Chapters 10 and 14).

In 1909, another prolific Late Jurassic dinosaur site was investigated in an area far removed from Utah - Tendaguru, in present-day Tanzania. The region was a German colony at the time (German Protectorate East Africa) and in 1907 Bernhard Sattler, an engineer with a German mining company, discovered some large bones there. Eberhard Fraas (1862-1915), of the Royal Naturaliensammlung (Staatliches Museum für Naturkunde) in Stuttgart, Germany then examined these bones later that year. Fraas caught amoebic dysentery while doing fieldwork before visiting Tendaguru, but he managed to make the four- to five-day hike to the field site to confirm that the large bones were indeed from dinosaurs. While he was there, he even directed some excavation and recovery efforts. Werner Janensch (18781969) conducted later expeditions from 1909 to 1913 and was ably assisted by Boheti bin Amrani, a native of the region (Fig. 3.12). After World War I, the area came under British control and expeditions from 1924 to 1931 were arranged through the British Museum, again using the expert guidance of Amrani. The logistics for these forays were daunting because, unlike the American West, no railroads went into the area. There were also few automobiles and no roads, so local workers were employed to carry the dinosaur bones away on foot. Through this labor-intensive method, the local people in the employ of earlier German expeditions carried out about 225 tons of bones, the hike from the site taking four to five days. Collectively, all work done in Tendaguru resulted in the uncovering of a new species of stegosaur, Kentrosaurus (Chapter 12), the theropod Elaphrosaurus (Chapter 9), and the ornithopod Dryosaurus (Chapter 11), but the deposit is best known for its diverse sauropod assemblage, consisting of Barosaurus, Brachiosaurus, Dicraeosaurus, Janenschia, and Tornieria (Chapter 10).

FIGURE 3.12 Boheti bin Amrani at Tendaguru of what is present-day Tanzania, uncovering a sauropod rib during one of the German expeditions to the region. Dr. Bernard Krebs, Lehrstuhl für Paläontologie der Freien Universität, Berlin/Dover Publications.

In South Africa, Richard Broom (1866-1951), originally from Scotland and yet another physician who was much more enthused about long-dead subjects than his living patients, published papers in 1904 and 1911 on a few dinosaur finds in the Karoo basin, an area well known for its vertebrate fossils. These papers were significant because no dinosaurs had been described from South Africa since the times of Owen and Huxley, so future workers were encouraged to explore more in this area. Sure enough, Sydney Haughton of England and E. C. N. van Hoepen of South Africa soon followed Broom's works in 1915 to 1924 and expanded upon the knowledge of Late Triassic dinosaurs (such as the prosauropod Melanorosaurus; Chapter 10) in that region.

Also working on Late Triassic dinosaurs, especially those of southern Germany, was Friedrich von Huene (1875-1969). Von Huene greatly expanded the studies of the abundantly represented Late Triassic prosauropod Plateosaurus. Early in his long career, he reviewed critically all of the previous classifications of dinosaurs and re-affirmed in 1914, on the basis of much evidence, the dual classification system of Saurischia and Ornithischia for the dinosaurs (Chapter 5). He also described, for the first time, dinosaurs from the Upper Triassic of Brazil and did fieldwork wherever he could find Triassic rocks, which included the five continents of Europe, North America, South America, Africa, and Asia. Because of his breadth of experience with these earliest of dinosaurs, he provided much knowledge toward their evolutionary history (Chapter 6), and in 1932 published a comprehensive evaluation of the Saurischia. He also was well known for his hiking ability, and while in his 80s decided to attend a scientific meeting by walking 150 km for three days across southern Germany.

Like von Huene, Richard Lull (mentioned earlier) was an important synthesizer of knowledge about Late Triassic dinosaurs, especially those of the Connecticut Valley. Much of his work was done at the same time as his German counterpart. Lull, a former student of Osborn, was the first person to begin the arduous task of reconciling and correlating Hitchcock's dinosaur tracks with potential tracemakers, which he did by examining new discoveries of body fossil of dinosaurs in the same area. This integration of body and trace fossil evidence of dinosaurs had been attempted in other areas before, but never to the extent that Lull pursued it. His efforts resulted in a much better model of how a comprehensive approach to dinosaur 3

fossils could enhance the quality of hypotheses about them. In 1915, Lull also reviewed all known fossil evidence (plants, insects, fish, reptiles, and dinosaurs) associated with Upper Triassic rocks of the Connecticut Valley, in an attempt to reconstruct the dinosaurs' paleoenvironments, one of the first serious studies of the paleoecology of a terrestrial ecosystem.

No history of dinosaur studies is complete without mentioning the Mongolian expeditions, first mounted by the American Museum and represented by the semi-legendary character of Roy Chapman Andrews (1884-1960). Chapman humbly began his career with the museum by performing janitorial duties, and eventually worked his way into the technical staff. Ironically, in light of his contributions to later discoveries, he was not primarily a dinosaur paleontologist and was mostly interested in studying mammals. Osborn, who became president of the museum in 1908, shared Andrews' interest in mammals, and Andrews persuaded him to mount a paleontological expedition to central Asia to search for the fossil ancestral remains of the most important mammals of all (to them), humans. Osborn agreed and the first Central Asiatic expedition, led by Andrews and accompanied by experienced paleontologist Walter Granger, went into the Gobi Desert of Mongolia in 1922. The trip failed in its goal to find fossils of humans, but did find the first confirmed dinosaur nests with eggs, although the identities of the egg layers were mistaken for the next 70 years (Chapter 9). French paleontologists had documented dinosaur eggs without nests in the nineteenth century. Skeletal material derived from this and successive expeditions from 1922 to 1930 included abundant specimens of the marginocephalians Protoceratops and Psittacosaurus (Chapters 7 and 13), the inappropriately-named theropod Oviraptor (Chapter 9), and the evil-looking Velociraptor and Saurornithoides (Chapter 9), all found in Cretaceous rocks.

Chapman has often been cited as the possible inspiration for the character Indiana Jones, a fictional archaeologist (someone who studies human artifacts, which is very different from a paleontologist: see Chapter 1). The producers of the Indiana Jones films have never admitted that Chapman was their source. Regardless, Chapman's expeditions and his exploits were certainly extraordinary for their time. He took advantage of his knowledge of Asian languages to work with his Chinese hosts and established his headquarters in Beijing; he navigated field crews in automobiles; and he arranged for the rendezvous of camel herds that carried gasoline and other supplies across the desolate terrain. Chapman was also an excellent marksman and was rarely photographed in the field without some type of firearm within his reach (Fig. 3.13). Bandits were bothersome in the region, and he reportedly shot some of them. Fortunately, most fieldwork in Mongolia and other areas of the world today is threatened more by bad weather or diminishing coffee supplies than hostile raiders.

In the late 1940s, Russian expeditions to Mongolia followed the American efforts Br through the auspices of the Russian Paleontological Institute, led by paleontologist fiA

(and famed Russian science-fiction writer) Ivan A. Efremov (1907-72) and her-petologist Anatole K. Rozhdestvensky. In these excursions they found more examples of the previously discovered Cretaceous dinosaurs of that region, as well as some important new finds, such as the ankylosaur Pinacosaurus (Chapter 12), hadrosaur Saurolophus (Chapter 11), and the large theropod Tarbosaurus, which is so similar to Tyrannosaurus that it is now considered an Asian variant of the species (Chapter 9). The continued success of the Russian expeditions ensured that more

FIGURE 3.13 Roy Chapman Andrews (right), in the Bain-Dzak area, Mongolia, with Late Cretaceous dinosaur eggs in front of him and his bandit-prevention device behind him. Negative No. 410760, Photo. Shackelford. Courtesy Department of Library Services, American Museum of Natural History.

investigators would follow; a Polish-Mongolian research group returned to the area in the 1960s, as did American Museum paleontologists in the 1990s. Renowned paleontologist Zofia Kielan-Jaworowska led the Polish-Mongolian expedition, which also included participants Teresa Maryanska and Halszka Osmólska, who are still considered to be Poland's leading experts on dinosaurs.

China has been one of the most productive countries for dinosaur fossils, and this status will most likely continue for many years to come. The long-known plethora of dinosaur bones in China led to initial studies, mostly by Westerners in cooperation with Chinese scientists, resulting, in 1922, in the description of Euhelopus, a Jurassic sauropod (Chapter 12). One of the pioneers of dinosaur paleontology was Yang Zhong-jian (1897-1979), known as C. C. Young in Western scientific literature. Yang, who officially became China's first professional vertebrate paleontologist in 1927, was also the co-discoverer of the first documented dinosaur tracks in China, which were found in Jurassic rocks of the Shanxi Province in 1929. In 1936, he led a combined Chinese and American group, which uncovered the unusually long-necked sauropod Omeisaurus (Chapter 10). Yang's studies in Canada, England, the USA, and Germany helped him to establish excellent contacts with Western scientists, which paved the way for exploration of the vast outcrops of Mesozoic strata in his country. Locations in China have produced one of the most productive dinosaur egg sites in the world (Chapters 2 and 8) and many species of feathered non-avian theropods and birds (Chapters 9 and 15).

Dinosaur trace fossils, other than tracks and nests, received some recognition early in the twentieth century, although some of them were not appreciated until recently. Coprolites were reported in dinosaur-bearing rocks by Hitchcock in 1844, but the first dinosaur coprolite was not interpreted until 1903 by C.-E. Bertrand of Belgium. His specimen came from the same Cretaceous deposit that provided Dollo with so many iguanodontian skeletons. After Barnum Brown interpreted gastroliths early in that century, von Huene in 1932 reported other gastroliths in association with bones of the Late Triassic prosauropod Sellosaurus (Chapter 10). In 1942, Stokes described a similar occurrence of stones found with Late Jurassic sauropod remains. W. D. Matthew first interpreted dinosaur toothmarks, which are often preserved in dinosaur bones, in association with a potential tracemaker in 1908. In this study, he noted that the tooth spacing of the Late Jurassic theropod Allosaurus matched the toothmarks on bones of Apatosaurus, a sauropod that lived at the same time. This approach provided an intuitive method for better determination of feeding relationships among dinosaurs (Chapters 8 and 9). Although they were always a part of dinosaur studies, dinosaur trace fossils began to gain more attention from dinosaur paleontologists in the latter half of the twentieth century, as trace fossils supplemented or, in some cases, surpassed the information derived from dinosaur body fossils.

0 0

Post a comment