by Vladimir ALIFANOV, Cand. Sc. (Biol.), Borissiak Paleontological Institute (Moscow); Sofia SINITSA, Dr. Sc. (Geol. & Mineral.), Institute of Natural Resources, Ecology and Cryology, RAS Siberian Branch (Chita)

Specialists and lovers of paleontology not once were in a quandary concerning the rarity of dinosaur habitats in a vast territory of Russia, especially noticeable in comparison with such neighboring countries as Mongolia and China. Indeed, to the north of the Asian desert belt rich in paleontological species, the frequency of fossils found in natural outcrops of root rocks decreases, but the number of findings associated with economic activity (road construction, mine and open-pit works) increases. The cause of such peculiarity is related in many ways to inaccessibility and turfed areas of many potential habitats. The progress in studies of dinosaur remains from Moscow, Kemerovo, Amur and other regions and areas of our country was discussed not once in mass media. Now we shall consider the findings from a recently discovered habitat in Transbaikalia.

We'll begin from afar. In 1993, an event took place, remarkable for the world cultural life of the last decade of the 20th century, namely, the American blockbuster Jurassic Park directed by Stephen Spielberg was released. The movie had a triumphant success throughout the world in many ways due to realistic representation of extinct pangolins, namely, dinosaurs. It is interesting to note that majority of fossil movie heroes

bear no relation to the Jurassic period*, as they lived later. However, this discrepancy in the science-fiction movie did not prevent it from playing almost a historic role associated with awakening of a widespread public

*Jurassic period is one of the three periods of the Mesozoic. It lasted in the interval from 200 to 145.5 mln years, followed the Triassic period (251-200 mln years) and preceded the Cretaceous period (145.5-65.5 mln years).--Auth.

interest in dinosaurs and turning them into an element of modern mass culture. New signs of the time appeared in the form of souvenirs, toys, book- and movie-production with pictures of Mesozoic pangolins.

But even against such background the news of the discovered unusual findings of dinosaurs in the Lower Cretaceous deposits of the Yixian formation in the northeast of China (Liaoning province) caused a sensation. Their striking peculiarity consists in a combination of the remains of the skeleton and integuments, which is unique for such ancient and big animals. Due to this fact, scientists managed to establish presence of feathering in representatives of different groups of dinosaurs. From now on, the problem (first of all, discussions) of the nearest relatives of birds is essentially concretized.

But still earlier the search for vertebrates in the Gobi desert brought many wonderful discoveries. The major part of their habitat, including that of dinosaurs, was fixed on the map by members of the legendary paleonto-logical expedition of the USSR Academy of Sciences, which worked in the territory of Mongolia in the late 1940s and was headed by professor Ivan Yefremov, a well-known scientist and writer. Today Gobi is a territory of the never-ending search by international groups of "hunters" for fossils, and information on their activities excites the scientific and near-science community from time to time.

But there is also something which neither Mongolia, nor China, nor any other country with dynamic development of paleontology can boast of. It concerns discovery of dinosaurs of the Late Jurassic period. In this context, scientists usually speak of Germany, where in the beginning of the second half of the 19th century they discovered Compsognathus, who was for a long time considered the smallest creature among his considerably taller relatives. Widely known are archeological excavations in early 20th century in the territory of Tanzania, which resulted in the discovery of Brachiosaurus brancai, capable, according to some reconstructions, to raise the head to an incredible height of 12 m. Within the interval

of these two events, scientists succeeded in extracting, from some archeological sites in the USA the remains of such Late Jurassic rare animals as Diplodocus, Stegosau-rus and Allosaurus. The enumeration of other forms will hardly exceed 25-30 names, which is a little less than diversity of dinosaurs of the same age revealed outside North America.

The list of the Late Jurassic dinosaurs does not include such species from Russia though their remains were found in the Moscow Region, the Southern and Eastern Siberia. The archeological materials from these regions far removed from each other is represented usually by individual teeth or bone fragments, which are hardly identified. Besides, the age of the rocks containing fossils corresponds to the Middle Jurassic and also to boundaries between the Middle and Late Jurassic or the Late Jurassic and Early Cretaceous. Thus, over a vast area of the northern part of Asia there was no single habitat until recently, which would correspond by the time of formation of its geological rocks to the interval of 160-145 mln years, i.e. the final space of time of the Jurassic. Against this background, the discovery of the remains of the Late Jurassic dinosaurs in Russia represents a notable event, which is even more meaningful in the light of shortage of similar data in the world and especially in Asia.

The new habitat is located in the central part of the Transbaikal territory on the south-eastern slope of the uninhabited creek valley of Kulinda. Here, already in the Soviet time, geologists laid prospecting trenches for comprehensive studies of volcanogenic-sedimentary rocks of the so-called Ukureisk suite, whose outcrops are widely represented on the regional geological map. A lot of time have passed but traces of the past field surveying are still evident. Moreover, the old trenches proved to be more preferable for paleontological search than weathered and grass-covered natural outcrops.

The parallel inspection of trench banks in Kulinda in the summer of 2010 revealed productivity of two closely spaced workings. In them organic remains are confined to layers of a fine-grained rock. The plants are represented by prints of thalluses of moss, horsetail footstalks, leaves

and seeds of the gymnosperms. Among invertebrates there are rare findings of the Notostraca order, Branchiopoda subsclass and insects. The ancient organisms proper are not often encountered, but traces of their activities are often observed. Among such fossils in Kulinda there are usually homes of caddis-flies and passages of mud-eaters. It was difficult to imagine that among the recent findings, a print of forelimb bones of a miniature dinosaur would be found on one of the plates.

In late September of the same year a small field party started from Chita to Kulinda for a detailed inspection of the bone rock outcrops. Unfortunately, the snow cyclone over the location shortened our work time to two days. But they proved to be enough to make a small collection of samples. After that it was necessary to understand in the office conditions whom the fossil remains had belonged to.

The general analysis of the collection of vertebrates from Kulinda showed that its major part belonged to small-sized dinosaur remains. The bones of numerous samples were represented only by prints on the rock. Besides, all elements of the skeleton are, as a rule, separated from each other. Only in rare cases two or three bones on the samples can be found in close proximity. Unfortunately, there are no or just a few skull remains in the collection, which are best suited for identification of the findings. But, even without them, some findings are distinctly indicative of their belonging to Theropoda and Ornithischia dinosaurs*.

The findings allow also to make other conclusions, for example, on predominance of remains of Ornithischia dinosaurs in them. Some bones look like bones of Psit-tacosaurus mongoliensis, small biped dinosaurs widespread during the Early Cretaceous in the territory of Asia. Besides, the collection includes samples, which do not permit to say that Ornithischia belong just to Psitta-cosaurus mongoliensis. Even the age, the Late Jurassic, is not applicable for the latter, because it is known that the heyday for Psittacosaurus mongoliensis fell on the second half of the Early Cretaceous.

It is notable that the discussion of the problem of "dinosaur-bearing" rock paleochronology started long before discovery of Mesozoic pangolins in the said rocks. In geological literature it is accepted to refer the time of deposit accumulation of the Ukureisk suite to the Late Jurassic. However, the efforts to confirm this conclusion by means of special approaches gave different results. For example,

* Theropoda and Ornithischia dinosaurs are large systematic groups (suborders, orders) of dinosaurs. Theropoda moved on two feet, most of them were predators; Ornithischia are considered vegetable-feeders, many of them moved on four feet.--Ed.

the palynological analysis, which implies detailed studies and comparison of fossil plant spores and pollen recovered from rocks with such material from other regions, where the age of the rocks raises no doubts, and points to the boundary between the Middle and Late Jurassic. Besides, the analysis of volcanites from the suite deposits by means of the potassium-argon method* provides a rather wide time space from 169 to 144 mln years. In other words, apart from the Late Jurassic it extends to the second half of the Middle Jurassic and even the very beginning of the Early Cretaceous. Against this background the data on fossil insects are of considerable importance.

Transbaikalia has been in the sphere of interest of paleoentomologists for a long time, who often published data of the analyzed findings from this region, including in a special monograph, made public almost quarter of a century ago. At that time specialists were inclined to the Early Cretaceous age of the Ukureisk suite. Today we can say that the insect complex from the last suite is similar by composition to the insect complex from the other, Glushkovsk, suite, which is widespread in Transbaikalia and much richer in fossil remains. As regards Glushkovsk beetles, dragon-flies, stone flies, bugs and caddis-flies, it is possible to identify their forms and groups typical of the Late Jurassic or, more exactly, of its second half.

* Potassium-argon method is used in isotope geochronology. It is based on determination of quantity of radiogenic argon accumulation in potassium minerals.--Ed.

The striving to completely understand the specifics and importance of the new habitat of dinosaurs presupposed detailed fieldwork, which was carried out early in the summer of 2011. This time field parties from the Paleon-tological Institute of the Russian Academy of Sciences (Moscow) and the Institute of Natural Resources, Ecology and Cryology of Siberian Branch of the Russian Academy of Sciences (Chita) joined efforts in a combined expedition.

The set task was accomplished with substantial replenishing of collection materials. We managed to find a key to understanding of some strange structures, but evidently having an organic nature, on the surface of several plates from the 2010 collection. Now it has been elucidated that they represent elements of dinosaur skin. It is explained through a series of samples, on which bone remains are associated with formations on the skin.

All such material is of exceptional scientific importance. Up to now, the recently discovered in Germany Juravenator affined to Compsognathus was considered the most known finding of the Late Jurassic dinosaur with skin prints. The rock surface with the embedded dinosaur bone remains revealed a small imprint of skin covering in the form of small protuberances. It is of interest that, judging by the findings in Liaoning, skin appendages of the late Theropoda resembled filiform structures or did not differ from down plumage, contour feathers and even remiges in birds.

Unique cases of preservation of skin cover structures in dinosaurs in general and in Kulinda specifically are closely associated with conditions of habitat formation. The main peculiarities of this process are clear already now. The rocks were accumulating at the bottom of an ancient lake, existing in a volcanic zone. Its banks were overgrown with horsetail in some places and large trees here and there. The vegetation provided a shelter and food to dinosaurs. Their food was in the form of fruits and seeds, as well as invertebrate animals, especially insects and their maggots. Naturally, the lake environment changed all the time. The lake water level changed even more often, sometimes essentially. The dinosaurs dying near the bank, got into a burial place, but only after immediate burying of their remains in the thick of the benthic sediment.

The high speed of burial is an essential condition of preservation of traces of skin covering. Of essential value is a fine-grained sediment, which does not ruin the most solid organic structures, to which bones and hard skin derivatives can be attributed in the process of its thickening. The chemically reducing medium is also important, which can counteract to the process of decomposition of soft tissues. However, it is hard to tell the cause of this unique natural phenomenon right away, as studies of the Kulinda collection are just under way.

Systematization of the findings, their identification and description are also ahead. Special priority should be given to the studies of skin cover remains. But until that time it is important to find out what kinds of skin coverings belonged to certain groups of dinosaurs. This is not so simple, taking into account fragmentation of all findings. It is also necessary to find additional arguments confirming the age of the Ukureisk suite as well as its analogs, for example, in China, where exist locations with single and fragmentary findings, whose age is often subjected to reassessment. This will probably allow to come closer to the solution of the fundamental problem: can the discoveries in Kulinda be connected with a new page of the dinosaur chronicle?

And the last remark. The central and local mass media immediately got interested in the developments related to the paleontological findings in Kulinda. In the everyday headline news such information seems exotic. We can understand those who, striving to deepen the effect, striking imagination, added something on their own and made a step, willingly or unwillingly, towards the expected, but far from the reality. The situation can be returned to the objective course only in one manner, namely, by establishing compliance between knowledge and actual facts, i.e. by means of the truth. Meanwhile, it seems no more accurate than it is described above.