by Vladimir ALIFANOV, Cand.Sc. (Biology), RAS Paleontological Institute, and Alexander AVERYANOV, Dr. Sc. (Biology), RAS Zoological Institute
The theme of dinosaurs and their time is presently as captivating as ever. Some countries (U.S.A., Canada, Japan, China) generously allocate funds for search, excavation and scientific processing of the remains of these ancient reptiles. Scientists obtain new, sometimes stunning, data about their physiology, ancestry and way of life.
The dinosaur studies date back to 1824 when the Oxford zoology professor William Backland announced at a meeting of the Royal Society about the finding in the Jurassic deposits on the southern coast of England of a jaw fragment belonging to a theretofore unknown big creature he called Megalosaurus (the Latin for a giant reptile). A year later Luis G. Mantle, a surgeon from a southern English town, presented data about the discovery of isolated bones in the local cretaceous rocks belonging to another giant nicknamed Iguanodon ("iguana-tooth") for the similarity of its teeth shape to that of some iguana lizards. Mantle also described a skeletal fragment of another big fossil reptile - Hyleosaurus.
On the basis of Backland's and Mantle's works, the English paleontologist Richard Owen propounded the kinship of all extinct big reptiles and grouped them under the term "dinosaurs". Justifying his point of view in 1841, Owen talked about dinosaurs as "secondary period pachydermates". At that time scientists applied the term of the secondary period to the Mesozoic era (249 - 65 mln years), and referred rhinoceroses, elephants and hippopotami to the pachydermates.
In mid-1800s, at the time of the London World Fair, the sculptor Waterhouse Hawkins exhibited in the downtown a series of full-scale dinosaur figures which reminded of enormous rhinoceros-like creatures with scaly skin. The press gave an extensive coverage to the exhibition of the monsters: they became known outside England, particularly in North America, where in New Jersey in 1858 the first intact skeleton of a dinosaur was discovered called Hadrosaurus. Its jaws looked unusual, like a duck bill. But most of all Joseph Laidy, the paleontologist who studied the find, was amazed by a strong disproportion of the creature's limbs which gave it a resemblance of a kangaroo. That helped make a supposition about the bipedal movement of the ancient reptiles.
The finding of intact skeletons of a meter-and-a-half tall carnivorous Compsognathus in the upper Jurassic (150 mln years) shale rocks of Germany and a two-meter tall herbivorous Hypsilophodon in early Cretaceous (125 mln years) chalkstones of England suggested that not all dinosaurs were giants. Some scholars, including evolutionist biologists Ernst Geckell (Germany) and Thomas Hucksley (UK), made note of the similarity between the skeletal structures of dinosaurs and birds, propounding the kinship of the two groups. But at that time so bold a hypothesis did not meet with understanding and was forgotten for almost a century.
April 1878 saw a new sensational discovery: miners near the Belgian village of Bernissar discovered an enormous clustering of dinosaur bones. Most of them belonged to Iguanodons. The excavation lasted more than 30 years. However, already a year later paleontologists managed to extract from the rock a 10 m skeleton and mounted it on a metallic frame in a biped posture. In 1905 the Royal Museum of Natural Sciences in Brussels displayed already a group of 10 of these ancient animals. The unusual exhibition met a vivid response of general public. The supervisor of the Bernissar excavation, paleontologist Louis Dollot, was one of the first to pose the problem of the causes of mass death of the fossil vertebrates subscribing to the idea of the natural origin of their "graveyards" as a result of some local calamities, like, e.g., floods.
The development of the Wild West in the late 1800s was accompanied by search for the antediluvian vertebrates'
remains. The venturous "hunting" of dinosaurs was most aggressively conducted by paleontologists Edward Cop and Othniel Marsh. They bought finds from chance collectors, hired special excavation teams often paying their own money. The spirit of competition urged these researchers to report new finds with the speed of lightning, sometimes in newspapers. The fuss resulted in numerous errors, confusion, reciprocal claims and jeer. And still, Cop and Marsh have made an enormous contribution to paleontology. They are the authors of almost 130 species of dinosaurs described in the period of 13 years, which seems incredible from the standpoint of the present day.
In the early 1900s paleontologists turned to the then barely accessible and little- investigated regions of Africa and Asia. An example of a transcontinental expedition was set by the Berlin Museum of Natural History whose fellows worked in Africa from 1907 to 1912. In Tendaguru (Tanzania) they discovered a big mass of fossil bones which belonged to some late Jurassic period (150 mm years) dinosaurs. The materials included fragmentary skeletons of several Brachyosauruses which were distinguished by massive limbs and a small head on a very long neck. Alive they weighed a few dozens of tons and for many decades remained unsurpassed as terrestrial heavy-weights.
From 1922 on Mongolia and later China (where over three thousand years back the finds of large teeth of early reptiles were purported to prove the existence of mythical dragons) hosted an expedition of the American Museum of Natural History (New York). In the very heart of Gobi Desert among the red cliffs of the Bain-Dzak area (Flaming Rocks) the scientists found sculls and skeletons of several small dinosaurs. The discovery of fossil eggs and even complete clutches of Mesozoic reptiles has become a real scientific sensation, since theretofore there had been no reliable data about the biology of their breeding.
The triumph of American paleontologists is somewhat overshadowed by the fact that the first species of Chinese dinosaurs were discovered and described by Russian researchers. All that started back in 1902 when Cossacks of Kasatkino village (about 400 km down the Amur river from Blagoveshchensk) crossed over to the opposite and at that time wild right bank in the Beliye Kruchi (White Cliffs) area presently known as Lung Gu Shang (Dragon Bones Mountain) where their attention was captured by large remains of some ancient animals protruding from a clift. At that time the Priamurskiye vedomosti newspaper of Khabarovsk reported: "...The bones are embedded in the rock mass of the ancient river bank laid of a blue conglomerate, under a three-sazhen deep layer of sediment sand, roughly at the height of 2 sazhens from the normal level. As can be inferred from a hasty study, the skeleton lies on its left side with the fore legs turned towards the river, occupying 5 sazhens in length. The special iron tint of the surrounding soil outlines what once was flesh on the frame. In the period of flood bones are washed out of the bank slope and fall on the coast".
The Amur river region branch of the Russian Geographic Society dispatched to the place of the find the amateur archeologist Alexei Gurov who assembled a small collection of bones and passed them to the museum of local studies in Blagoveshchensk. The newspaper feature reprinted by the Yearbook of Geological and Mineralogical Studies in Russia caught the attention of scientists from the Russian Geological Committee (Geolcom). During his 1914 Far East expedition the paleobotanist, future corresponding member of the USSR Academy of Sciences, African Krishtofovich visited the Beliye Kruchi. On return to Petrograd he handed a large fossil bone he had picked up there to the paleozo-
ologist Alexander Ryabinin who identified it as a dinosaur tibia fragment.
In the summer of 1916 a Geolcom exploration team arrived at Beliye Kruchi. Its field season culminated in a few dozens of poods (1 pood = 16 kg. - Tr. ) of broken fossil bones. The next-year visit yielded an incomplete dinosaur skeleton which together with other finds was without peculiar problems transported to the capital. The civil war and devastation hindered their studies till 1924. Specially for that Dr. Ryabinin studied the remains of dinosaurs in the museums of Germany, Belgium and UK, and in late 1925 reported the first results of the processing of his own collection at an open session of Geolcom. The paleontologist attributed the skeleton discovered in 1917 to the group of duck-bill dinosaurs under the name of Mandschurosaurus amurensis. He also described two more species of dinosaurs on the basis of other fragmentary material.
In 1976 - 1979 Chinese paleontologists conducted excavations in the Beliye Kruchi area. The three practically intact Mandschurosaurus skeletons they have discovered are presently exhibited in Harbin in the museum of the province of Heilungkiang. Since then field works have been regularly conducted in various regions of China by local and foreign specialists who consistently discover new forms of dinosaurs. The world renown has been acquired by the Dashangpu site (the province of Szechuan) where complete fossil skeletons of several previously unknown forms of the early animals were uncovered, dating back to the Middle-Jurassic period. The province of Liaoning is more and more often associated with sensational paleontological discoveries as its soil has produced skeletons of reptiles and birds, often with imprints of integument. The study of these materials has proven that small predatory dinosaurs had feathering! Some of them were covered with floss, others with feathers with broad fans on the tail and fore limbs. That has conclusively substantiated the hypothesis of the affinity between dinosaurs and birds.
In the recent decades the scope of paleontological studies has grown world-over as suggested by the sensational reports of dinosaur remains finds in Australia, Antarctica and in many countries of Asia, Africa, South America and Europe. It is also proven that the broad geographical area of dinosaurs is related to the existence of the super- continent of Pangea circa 220 mln years ago which at the time integrated all major land masses. Any regional discovery today not just reveals something new of the geological past of a country, helps to understand the significance of the find from the universal perspective, but also casts a new light on the intrigue of the past search.
Until 1900s practically nothing was known about dinosaurs in the territory of the Russian Empire, unless we count in the finds in Volhynia-Podolia (Ukraine) and Kursk Gubernia, the quality of which prevents accurate estimations. For the same reason, hardly belonging to a dinosaur is the spinal bone from the marine sediments of the southern Ural region, the finding of which was published by the paleontologist Nikolai Bogolyubov in 1912.
The first doubtless dinosaur bone (a foot fragment) to be found in the territory of Russia comes from a coal mine near the station of Tarbagatai in Chita region. It had got into the hands of Dr. Ryabinin even before he was introduced to the materials from the Amur region. In 1915 he published the description of the find which he defined as a new species: Allosaurus (?) sibiricus. In the years to come Dr. Ryabinin would repeatedly turn to these ancient animals in his works. The scientist's last works were devoted to the description of the hadrosaur Orthomerus weberae (the specific name was given in honor of Gertrude Weber who had discovered the bones) from the Crimea and came out in 1945
and 1946, after the author's death in besieged Leningrad.
In 1928 the state of paleontological studies in the USSR was analyzed by Academician Alexei Borisyak in an article published in the Nature magazine. He recognized the lag of the domestic vertebrate paleontology behind this science in America and saw the source of transoceanic specialists' success in the initiation of individual search irrespective of geological explorations. Such approach has made it possible to discover a substantial number of new sites and form the cadres of professional "hunters for mineral resources", as excavations of vertebrates require special skills and considerable efforts perpetrable by a well-organized and trained team only. Scientific projections and research planning are another important constituents of success. All that combined with considerable funding has allowed American museums to arrange expeditions to almost any country of the world and realize the broad tasks they have set themselves.
New paleontological discoveries in the Old World, including Asia, in Academician Borisyak's opinion, promised brilliant vistas to Russian paleontology. At his initiative, on the basis of the Academic Geological Museum in Leningrad, the Paleontological Institute of the Academy of Sciences was created (initially, the Paleozoological Institute). That happened in 1930, and four years later the new institution moved to Moscow together with the Presidium of the USSR Academy of Sciences. The Institute's activities resulted in remarkable success in the studies of Palaeozoic and Cainozoic vertebrates, but it was not so with Mesozoic reptiles.
By that time the promising finds of cretaceous dinosaurs in Kazakhstan and Central Asia were widely known. Geologists supplied stunning reports about the whole "ridges" made of thousands of dinosaur bones extending for tens of kilometers beyond the horizon. The Paleontological Institute staff member Ivan Yefremov who later became a major scientist and famous science-fiction writer, volunteered to study the new sites. Unfortunately, what he saw were just broken and rounded bones "mostly defying study". From Yefremov's point of view that was an evidence that those sites which stretched sub-latitudinally along the northern edge of Central Asian mountain systems had been formed by washing out and redeposition of bedrock in subsequent eras. Such categorical an opinion restrained an active dinosaur search in the Soviet Union.
Within the Paleontological Institute work program outstanding results were yielded by the field works of 1946 and 1948 - 1949 in Mongolia. They had been planned for 1941 but were disrupted by the Great Patriotic War. However, already in the first post-war year the Soviet government allocated funds for the project. The prompt solution of many organizational issues was greatly facilitated by Stalin's personal interference.
The reconnaissance trip of a team led by Ivan Yefremov resulted in the discovery of a large number of new sites, some of which, like those of the Nemegetu basin (Nemegetu and Altan-Ula, or Dragon Grave, in South Mongolia), contained remains of gigantic dinosaurs. The follow-up was a second larger scale expedition of 1948 - 1949. It discovered complete skeletons of several new forms of large dinosaurs at once and delivered them to Moscow. Later Yevgeny Maleyev who devoted several publications to the studies of the first Mongolian yields, described new species of the Tyrannosaurides family under the name of Tarbosaurus efremovi, in honor of his colleague and field work team leader.
The space of the Paleontological Institute Museum was too small for the huge dinosaurs from Mongolia, therefore the USSR Academy of Sciences resolved to erect a special Paleontological Museum building in Moscow. Unfortunately, the organizational and financial problems resulted in a drag, and the exhibition was opened in 1987 only. There the extinct reptiles occupy a spacious two-level hall featuring more than 15 skeletons. One of the podiums is occupied by a Hadrosaur skeleton discovered in 1961 in the south of Kazakhstan in the bedrock. The staff member of the Paleontological Institute Anatoly Rozhdestvensky has termed it Procheneosaurus convincens which means "indisputably convincing", i.e., being an undoubtable evidence of the deposit of the formations with the dinosaur's remains in the Cretaceous period without any subsequent redeposition.
The Paleontological Institute's dinosaur collection was also replenished by the Joint Soviet-Mongolian Paleontological Expedition (JSMPE) organized in 1969 by the academies of sciences of the USSR and Mongolia. During the period of the two countries' Paleontological cooperation almost 50 volumes of works were published, several of them devoted to Mongolian dinosaurs. The monograph by R. Bars-bold published in 1983 has not just summed up the perennial gatherings but has largely given an impetus to the notions of the kinship and systematization of large predatory dinosaurs. Today no major theoretical generalization regarding this group can disregard the Mongolian materials whose state of preservation is often exemplary.
However, many Cretaceous profiles of Mongolia still await study. In hope for new paleontological discoveries international expeditions of North American, European and Asian scientists head for South Gobi. JSMPE, now the Joint Mongolian-Russian Paleontological Expedition, still functions, although its work scope has sharply reduced in the recent ten and a half years for economic problems.
While the efforts of the Paleontological Institute scientists were concentrated on the studies of fossil vertebrates of Mongolia, the Leningrad scientist Lev Nesov took an interest in Mesozoic reptiles that had lived in our territory in ancient times. In his monograph devoted to dinosaurs of Northern Eurasia and published in 1995 he,
in explicit polemic with Efremov's opinion (who is considered to be a founder of taphonomy, a teaching about the common laws of the burial of fossil remains), maintained that from isolated bones and teeth one could infer the real incidence of certain groups. That allowed to get more or less viable data of, e.g., the relative biomasses of predatory versus herbivorous dinosaurs. Nesov's articles and books published in 1980s and 1990s provided data about the makeup of dinosaur faunas and descriptions of their known and new locations.
In the recent years dinosaurs have been found in various territories of our country: in Volga area, Belgorod and Moscow Regions, Krasnoyarsk Territory, Trans-Baikal area and Yakutia. Several skeletons of small herbivorous dinosaurs of Psittacosaurus genus (parrot-like dinosaur) were discovered in early-cretaceous (120 mln years) rock near the village of Shestakovo in Kemerovo Region. The psittacosaur finds are accompanied by a rich variety of small vertebrates (salamanders, lizards and crocodiles). That makes the South Siberian site unique among its counterparts along the whole span of Asia.
The works presently in progress in Amur Region deserve special mentioning. Back in the post-war years the natives discovered large fossil bones in the rock outcrops near the western outskirt of Blagoveshchensk. In the summer of 1951 these places were visited by A. Rozhdestvensky. Trial excavations confirmed the presence of dinosaur remains but provided no substantial ground for paleontological exploration. In the early 1980s paleontologists from the Amur Joint Research Institute of the Far Eastern Branch of the USSR Academy of Sciences (Blagoveshchensk) tried to retrieve substantial materials from this locality. Meticulous excavations conducted for some years under the leadership of Yuri Bolotsky have yielded numerous isolated bones, while the find of a large scull fragment of an ancient animal resulted in 1991 in the description of a new dinosaur species termed Amurosaurus riabinini in honor of Alexander Ryabinin.
Presently, the search is predominantly conducted in Arkhara area in the south-east of Amur Region on the Kundur site where in 1999 for the first time in Russia a skeleton of a late-cretaceous (70 mln years) dinosaur was discovered with all joints intact. It took 3 seasons for specialists of the RAS Amur Joint Research Institute, the RAS Paleontological Institute and the Royal Institute of Natural Sciences of Belgium (Brussels) to extract the remains of the 10 m tall giant from the bedrock. Now the description of this reptile called Olorotitan arharensis (gigantic swan of Arkhara) is published.
Just like Amurosaur it belongs to the Hadrosaurus group but has unusual for its genus shape of a large and hollow bone pecten on the head and unusually long neck. Judging by the positioning of some skullcap bones, Olorotitan was one of the most "advanced" Hadrosaur representatives.
Presently, the dino collection from Kundur includes a few thousand bones mainly belonging to hadrosaurs. Remnants of other groups of the ancient reptiles are rather rare. The gatherings contain, e.g., teeth of two species of small predators and of gigantic tyrannosaurides.
Some of the Kundur finds look mysterious. Among them small series of isolated fore caudal vertebras reminding in size and structure of the corresponding skeletal elements of Stegosaurus, ostensibly extinct in Asia even before the late Cretaceous period. However, it has transpired that some sauropods are marked by a similar structure of the same vertebras. If it is so, then we should recognize that in the late Cretaceous period the Far East was populated by small in size congeners of Brachiosaurs.
All those data are relevant for the reconstruction of the ancient reptiles' habitat, determination of the relative age of the rock containing their remains in the Far East, China and Mongolia as well as paleobiogeographical ties between the faunas of PaleoAsia and North America in the late Cretaceous period.
The bone-bearing horizon in Kundur is about 1.5m thick consisting of two heteralevel layers. The including proluvium argillaceous deposits with the abundance of unrolled small-debris material evidence: about 70 mln years ago the highlands which surrounded the vast Bureinskaya basin produced powerful mud avalanches which killed and buried in their mass great numbers of animal populations.
The study of bone-bearing deposits in Amur region shows that the Far-Eastern dinosaurs lived in the conditions of emerging cold and dry climate. It is important to identify when that happened: at the beginning, the middle or the very end of Maastrichtian which is considered to be the last Cretaceous age. This problem still awaits clarification.
By the end of the field season of 2002 the excavation area in Kundur reached about 100 m 2 , while in tentative estimates the productive formation is tens or hundreds of times larger. That opens up prospects for further work. But even now Kundur is an example of the most successful search for the remains of dinosaurs in the territory of Russia. No doubt, this experience will be relevant to the results of dinosaur studies not only in Amur region but in other regions of the country too.
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