A concise history of Russian palaeoentomology
Fossil insect studies in Russia started just before the establishment of the Palaeontological Institute. They were initiated by a renowned entomologist A.V. Martynov, who became a founder of the Laboratory of Entomology in this Institute. During the years of its existence, the Laboratory of Arthropods accumulated the most extensive collection of fossil insects and arachnids comprising approximately 200 000 specimens and being one of the best collections in the World. Hundreds of fossil-bearing sites have been discovered and studied in detail for the first time; they include such unique faunistic and preservational Lagerstaetten as Permian Tshekarda and Soyana, Triassic Madygen and Dzhailaucho, Jurassic Karatau, Cretaceous Baissa and Bon-Tsagaan, and Late Cretaceous amber-like resins of Taimyr. From the origin of the Laboratory until the present day, research is mainly focused on phylogeny. For the first time in palaeoentomology, the Laboratory staff turned towards a deep investigation of the history of larger taxa, mainly those of the order rank, from the point of their appearance in the palaeontological record instead of investigaton of local faunas. The geological history of some orders (dragonflies and damselflies, mayflies, bugs, beetles, true flies, caddisflies, wasps, orthopterans, grylloblattids, stoneflies) has been traced comprehensively, and new phylogenetic schemes put major changes in previous opinions. A.V. Martynov invented a new system of the class of Insecta, which has been widely adopted since then and is still in use. However, accumulation of new data led to its revision, and in 1980 A.P. Rasnitsyn proposed a new and essentially modified system of the class, which inspired a vivid dicussion and is gradually getting recognition. Naturally, important and interesting morphological data were obtained during taxonomical and phylogenetic investigations. Thus, B.B. Rohdendorf was one of pioneering researchers of morphology of insect wing articulation structures, which are currently broadly used in taxonomy.
Palaeoecology of insects became another important aspect of palaeoentomological research in the Paleontological Institute. Special work in this area was commenced relatively late. First attempt of that kind was undertaken by E.E. Becker-Migdisova on the material of Miocene insects from the Stavropol' Territory. Later, insect palaeoecology, evolution of insect ecology, their role in palaeocommunities, and reconstruction of ancient terrestrial and freshwater ecosystem structure were covered largely by N.S. Kalugina, V.V. Zherikhin, A.G. Ponomarenko, and N.D. Sinichenkova. A series of original conceptions which importance goes far beyond borders of palaeoentomology has been proposed; they include a hypothesis of biocenotic regulation of evolutionary processes, a hypothesis of considerable eutrophication of continental water bodies in the mid-Cretaceous, a scheme of crisis development in biological assemblages, and others. Large-scale changes of non-marine biota near the Early and Late Cretaceous boundary have been paid a special attention. The most exciting results have been yielded by analysis of changes of terrestrial and freshwater insect diversity and their comparison with diversity dynamics of other organisms performed by A.G. Ponomarenko and V.Yu. Dmitriev. Study of Quaternary insects undertaken in the connection with climate change by S.V. Kiselev, V.I. Nazarov, and F.A. Bidashko and continued by S.A. Kuzmina deserves to be mentioned as well. Investigation of fossil insect gut contents, which has been recently commenced by A.P. Rasnitsyn and V.A. Krassilov, represents an entirely new approach and gave exceptionally interesting results from the palaeoecological point of view.
Finally, mentioned should be work in the area of ichnology (investigation of fossil caddis cases by I.D. Sukacheva in co-operation with O.S. Vyalov, which supplied us with a unique information on evolution of complex behavior) as well as in taphonomy and, in particular, in insect burial in modern plant resins (V.V. Zherikhin and I.D. Sukacheva).
The Present State and Tasks of Palaeoentomology
Palaeoentomology, or science about fossil insects, millipedes and centipedes, and non-marine arachnids, is small in terms of a number of its students but large in terms of the width of its domain and in terms of efforts required to reach the level of excellence achieved by its sister branches, palaeobotany and vertebrate palaeontology. Palaeoentomology is a rather old field; the first insect fossils (inclusions in Quaternary copals) were described by Bloch (1779) according to standards currently considered as valid only 21 years after the start of zoological nomenclature by Linneaus (1758). Even if someone count the age of palaeoentomology starting from the large-scale description of fossil material (Germar, 1837, 1839), not from that date, this is more than a century and a half.
Until the 1880's, it was mainly palaeobotanists, geologists, or entomologists, who incidentally produced descriptions of fossil insects; their natural unit of research was an insect fossil assemblage from a fossil site or a group of such sites. Later appeared specialised entomologists working at a global scale and analysing among other questions, phylogenetic relationships of fossils; those are Samuel Hubbard Scudder (1837-1911) and particularly Anton Handlirsch (1865-1935). The present state of palaeoentomology has been determined mostly by efforts of Frank Morton Carpenter (1902-1994) and Andrei Vassilievich Martynov (1879-1938). Carpenter succeeded in rising the standard of palaeoentomological description, especially description and illustration of wings, and compiled a modern and fundamental compendium of fossil insects (Carpenter, 1992). Martynov provided a new (since Handlirsch's one) synthesis of insect palaeontology, taxonomy, and phylogeny, and having found the Laboratory of Arthropods in the Palaeontological Institute of the Academy of Sciences of the USSR (currently, the Russian Academy of Sciences), established a new style of palaeoentomological research, team-driven research by students specialising in different insect orders. Martynov's successor Boris Borissovich Rohdendorf (1904-1977) and his colleagues realised that program having risen the standard of palaeoentomological research even higher. In particular, a high standard of description and analysis of the body morphology of fossil insects has been achieved, first of all, by A.G. Sharov (1922-1973).
As a result of all the above efforts, we have now around 10 000 palaeoentomological publications and 20 000 described valid species of fossil insects. Several compendia of variable coverage are available, but regrettably, all of them are outdated. Even Carpenter's "Treatise" (1992) is compiled up to 1983, and is not quite complete even to that date; "The Fundamentals of Palaeontology" (1962) are even more outdated and much incomplete outside the territory of the former USSR. Recently published History of Insects (2002) presents an original synopsis and analysis of palaeontology and evolution of insects; however, it predominantly covers family or higher-ranked taxa.
Since Handlirsch's time, there has been no world-wide species-level synopsis of fossils. There are several world-wide monographs and catalogues of major insect orders that extensively cover palaeoentomological material, as well as numerous monographic publications on lower-ranked taxa. There are abundant monographs and serials that concentrate and analyse information on taxonomic composition, ecological organisation, and geological settings of various local and regional insect fossil assemblages. Even more copious are papers dealing with ecological features of various fossil insects, millipedes and centipedes, and non-marine chelicerates, their interconnections between each other and with other organisms, their stratigraphic and geographic patterns, and the dynamics of their diversity. Yet all these efforts are not sufficing for understanding even basic features of the taxonomic, ecological, and geographic history of our objects.
Indeed, the palaeoentomological record is richest in Europe, where, however, the majority of descriptions are now woefully outdated. Until recently, such record was almost non-existent on all the Gondwanan continents, but the situation has been changing radically, albeit insufficiently in South America and Australia. It has started to change in Africa, and is almost stagnant in India and Antarctica. This is particularly disappointing with regard to India; even the existing collection of Jurassic insects from the Kotá Formation remains almost untreated. The south-eastern Asian record is typically poor, being rich only in China, where the quality of descriptions is often inadequate. Fortunately, we can currently observe a rapid improvement in this area as well.
Stratigraphic gaps in the palaeoentomology are not less painful. Some of them are understandable, like the pre-Namurian Carboniferous gap; the oldest insects might inhabit such taphonomically unfavourable environments, as inland forests. However, this is not the case for the most striking Lower Triassic gap; for the Permian-Triassic transition was difficult but hardly catastrophic for insects at least. Equally enigmatic is the rarity of Jurassic insect fossils on all continents outside Eurasia.
As it have been already mentioned, diverse palaeoecological investigations ranging from local to global scale have been conducted. These range from ecological reconstruction for a particular taxon or an entire insect assemblage at a particular site, to the restoration of the landscape, climate, structure, and succession of past biocoenoses, as well as changes among all these features in time and space (these have been partially summarised in the History of Insects). We have reliable and detailed reconstructions of examples of interactions between different organisms based on both direct and indirect evidence, such as the gut contents of insect fossils, various traces of organismal activity among different organisms, and morphologically reflected adaptations of such interactions. This research is highly inspiring and suggestive, and yet is highly insufficient even for rough understanding of organisation of communities of our objects in various periods of the past. The same is true for biogeography of ancient insects, millipedes and centipedes, terrestrial and freshwater arachnids, for dynamics of their taxonomic diversity, etc.
The taxonomy of fossil insects is full of gaps as well. There are no appropriate synopses of the millipedes and centipedes and chelicerates. For insects, the best example is the case of cockroaches that are simply omitted in Carpenter's Treatise because of the chaotic state of their taxonomy. Due to well known problems in the classification of beetle fossils, only a tiny fraction of the immense accumulated collections has been described taxonomically so far. The fossil record of moths and butterflies is also highly inadequate.
Insect ichnology, or the study of insect, millipede and centipede and non-marine chelicerate trace-fossils, is still in its infancy; chemo- and micropalaeontology are practically non-existent, although present technologies make their fast development possible, and the importance of this approach is beyond doubt. For instance, lepidopteran scales occur in palynological samples, and thereby they could substantially improve the lepidopteran fossil record.
In view of these problems and gaps, which goals may be currently considered as the most urgent for palaeoentomology?
To develop successfully, any science needs abundant and systematically arranged material data, and its methodology being refined and widely appreciated. I have already attempted to outline the priority of tasks in accumulation and systematisation of fossil material, and I would like to concentrate now on methodology.
The methodology of palaeoentomological is diverse and complex. One of its most important and most underdeveloped branches is taphonomy, i.e. science about the mode and pattern of insect burial. Fortunately, a thorough review of the current state of insect taphonomy, its achievements and problems, has been prepared (and being applicable to millipedes and centipedes and non-marine chelicerates) and is available for a reader in the History of Insects (Zherikhin, 2002). Hopefully, this volume will provide a further rapid development of terrestrial and freshwater arthropod taphonomy. Many other aspects of palaeoentomology in general, and its methodology in particular, are also reviewed in this book to demonstrate the extent and limitations of our knowledge and our ability to increase it. It is not fully appreciated, for example, that the study of fossil insects principally differs from that of living insects in research methods and much less so in ways of interpretation of obtained data. The reason is that extant insects are also often studied fixed and flattened, e.g., slide-mounted, or badly incomplete, which is often in the case of old type specimens, so that arising problems are nearly universal. By contrast, when a palaeoentomologist interprets what is observes under his or her microscope, he or she must thoroughly consider circumstances and agents affecting pre-burial, burial and post-burial processes that formed fossil material. An experienced palaeoentomologist does most of this nearly unconsciously, and this may be the reason why this most important and unique part of our methodology is so elusive to others and is consequently so poorly discussed.
The above concerns primarily how we see, depict, and describe our fossils. Further interpretative steps, such as reconstruction of the phylogeny, ecology, and biocoenotic interactions, the pattern of spatial distribution, diversity and its dynamics, etc., are more integrative and needs more explicit analysis. These steps are often being described explicitly, and they do sometimes differ strikingly from those of neoentomologists. This is characteristic, in particular, of taxonomy, where cladistic methodology faces stronger resistance from many palaeoentomologists. Nevertheless, these more developed aspects of our methodology also need greater refinement.
Still more obvious is how much we have to do in collecting new material to make our data evenly representative through time and space, and how much exciting information may be extracted from the material already accumulated. Yet I would like to turn to another point; how our data, knowledge, and experience may be made more available to our colleagues.
We palaeoentomologists are few. It is true that some time ago we were even much fewer. However, interest in the geological past of insects and other non-marine arthropods is clearly growing, and the number of both professional and amateur palaeoentomologists is increasing rapidly everywhere, especially in countries, where they were particularly rare, for instance, in Brazil, Argentina, and Spain. Another important tendency is improvement of the quality of publications. Contribution of the technical progress to this process is beyond doubt, both in making the activity of an individual student more efficient and facilitating communication and co-operation. Of course, there are negative tendencies as well, and particularly the general decrease in the popularity and support of descriptive biology, in contrast to so-called ecology ― which is, in my eyes, not a scientific discipline but politics using ecological rhetoric.
Anyway, we palaeoentomologists are few, and this is both for worse and for better. It is naturally for worse, since we are unable to explore an immense research field and the existing collections in a reasonable time. But it is also for better, not the least because we are at less risk of treading on somebody else's toes while selecting our personal patch to plough. It is advantageous because we are in a better position to organise our communication so as to share our knowledge more easily.
There are many ways to do so. The newly launched International Palaeoentomological Society instituted at the Second International Palaeoentomological Congress that was convoked in Kraków (Poland, September 5-9, 2001), should be of considerable benefit, with its regularly assembled in 3-year period meetings plus related Palaeoarthropodological Congress and Congress on Amber Inclusions in between them, a newsletter, our own journal (in due course), and an active web site that can contain rich and timely information. No less urgent now is the revival of the project on an international database of fossil insects. The European project, declared several years ago, failed to reach its announced aim. It seems timely to analyse the causes of that failure and to work out a less ambitious but more realistic program. As I see it, this new database project should not be excessively complex but rather fast, versatile and compatible with other systems of database management to allow the entry of data from various local and personal databases created by different specialists. This would make a timely start possible by combining and sharing huge databases already accumulated by many people and institutions. It would also make possible improving the software gradually and concurrently with the data accumulation. The most important thing is rapid and effective bringing together efforts of specialists, who are interested in building up such a co-operative database, making results of their efforts more open, and through that inspire the curiosity of other colleagues. Regrettably, their interest in such a co-operation results mainly in chatting.
But perhaps the most urgent, to my opinion, is further development of research co-operation. It happened that we have only one formally organised team of taxonomically specialised, professional palaeoentomologists, namely those centred in Moscow, and even this team alone is unable to produce a desirable level of treatment of entire insect diversity of a reasonably large locality. Multidisciplinary study of local and large-scale fossil assemblages is by no means as interesting and important as tracing the history of particular insect taxa, so growth of research co-operation is unavoidable. Many of us have rich experience in such co-operation including international co-operation, as shown by numerous joint publications over the last two decades. And yet many fossil assemblages of the utmost importance await comprehensive study. Here, I would like to mention only a few of the most important Lagerstaetten, viz. the Permian locality of Tshekarda in the Urals and Elmo in Kansas, the Triassic locality of Madygen in Fergana and the Molteno in South Africa, the German Lias, Cretaceous deposits of Santana in Brazil, Orapa in Botswana, Koonwarra in Australia, Canadian and New Jersey fossil resins in North America, and several Eurasian Lagerstaetten, such as Purbeck and Wealden in England, Baissa in Siberia, Bon-Tsagaan in Mongolia, Yixian, Layiang and Daohugou in China, and Cretaceous amber in Spain, Lebanon, and Burma. Particularly numerous are major Tertiary Lagerstaetten deserving of international attention, these are Baltic and Dominican amber, largest European assemblages of compression fossils, Florissant and Green River in North America. The last locality deserves particular attention. The Smithsonian Institution has accumulated nearly 100 000 specimens of fossil insects and other arthropods. It is the World's largest collection that come from a single formation at a single place; and it is probably the most representative amongst largest palaeoentomological collections, since it has been gathered mainly by one and the same pair of very skilful hands and eyes and with minimal prior selection. It is nearly a perfect springboard for further investigation of biota and environments of the past, as well as for improvement of research methods.
In short, palaeoentomology develops instantly, and the most obvious course of its development lays in strengthening and broadening collaboration of researchers for the welfare of each of them and palaeoentomology upon the whole. I hope, that a new-born International Palaeoentomological Society will also play an important role in this process.