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Owen was an establishment figure par excellence. He knew the Prime Minister William Gladstone very well in the 1860s, and had even been a tutor in natural history for the royal children at Buckingham Palace. No museum figure of modern times has been so close to the seat of power. Owen knew how to make things happen, and his persistent lobbying eventually yielded dividends in the form of Alfred Waterhouse’s vivid new building. Prince Albert, Queen Victoria’s beloved husband, was sympathetic to housing natural history collections in his developing cultural ‘theme park’ in Kensington, and opposite the industrial crafts of the ‘V&A’ along Exhibition Road. The Prince’s effigy, covered in gold, still broods over the Albert Hall a few minutes’ walk north of the Museum on the edge of Kensington Gardens. Owen was trusted to design a museum with sufficient seriousness to satisfy the Victorian sense of self-improvement through knowledge, or as the Keeper of Mineralogy put it in 1880: ‘the awakening of an intelligent interest in the mind of the general visitor’. Owen certainly intended to display in the main hall what he called an ‘index museum’ of the main designs of animals in nature, intended to be a kind of homage to the fecundity and orderliness of the Creator. However, by 1884 when the Museum formally appointed its first Director, William Flower, the principle of evolutionary descent seemed to be the only acceptable way to organize nature for explanatory purposes. The cathedral had been hijacked for secular ends, and the temple of nature had become a celebration of the power of natural rather than supernatural creativity.
Richard Owen in old age with the skeleton he helped to reconstruct of theextinct New Zealand moa, the world’s largest bird.
Richard Owen with moa skeleton. From Richard Owen, Memoirs on the extinct wingless birds of New Zealand. Vol 2. London: John Van Voorst, 1879, plate XCVII.
There are large marble statues of both Charles Darwin and his famous public champion, Thomas Henry Huxley, on display in the Natural History Museum. There is also a bronze of Richard Owen. Few visitors seem to notice them, or pause to read their plaques. Darwin and Huxley look out over a refreshment area on the ground floor, so the great men contemplate a clutter of tables rather than the grandeur of nature.* (#litres_trial_promo) A seated Darwin is in the splendour of his old age, every inch the bearded patriarch; Huxley, seated nearby, is brooding and imperious. Richard Owen stands around the corner, in academic dress, halfway up the main flight of stairs facing the main entrance. His hands are slightly outstretched, and at least to my eye there is something clerical about him, as if he were offering a blessing rather than a specimen, although his face is still fierce and commanding. The formality and equality of white stone have somehow ironed out the differences between Darwin and Huxley; it is their enquiring spirit that pervades the Museum. They have become the saints in the place. Oddly, the dark bronze of Owen seems more out of place, as if its metallic heaviness were symbolic of the arguments lost to the presiding genius of Darwin, beatified in marble.
It is curious to reflect that the differences that separated these two men, the bronze and the marble, still count today, well over a century later. London is dotted with memorials to its great scientists. Newton is in the Royal Society; Michael Faraday stands outside the Institute of Electrical Engineers on the Embankment. Yet nobody challenges the insights that Faraday or Newton had into the workings of the world (while recognizing, of course, that understanding has also moved on). Yet there are those who would still side with Owen, against Darwin and Huxley, on the subject of biological evolution – they would seek to reverse their respective historical roles and, no doubt, cast out the marble statues. This view is predicated on the idea that evolution is ‘just a theory’; and that other theories – which in fact mean only ‘creation science’ or its close relative ‘intelligent design’ – deserve an equal airing. There are some important and interesting matters hidden away in this argument. There are, indeed, some theoretical issues in evolutionary theory that are still being investigated; indeed, there are whole journals devoted to such questions. Furthermore this is what science is about – probing questions, not just giving ‘the answer’. Physics and chemistry are no different in this regard – they are full of theories in the process of being tested. So are cosmology and economics. But the crux for the statue of Darwin is a third consideration. The issue of ‘creation science’ is not the kind of theoretical question about kin selection that might be found in a scientific journal, it’s about whether evolution happened at all. Put bluntly, it is about whether or not we share a common ancestor with a chimpanzee. The descent of all life through evolutionary processes is not a ‘theory’ in the sense that the creationists would have us believe. So overwhelming is the evidence for evolution by descent that one could say that it is as secure as the fact that the Earth goes around the Sun and not the other way around. Every new discovery about the genome is consistent with evolution having happened. Whether we find it appealing or not is another question, but personally I like being fourth cousin to a mushroom, and having a bonobo as my closest living relative. It makes me feel a real part of the world. So those who promulgate ‘creation science’ are trying to pull off a trick of intellectual legerdemain, a mind jump concealed by jiggery-pokery, mixing in the truly theoretical with what most scientists would simply refer to as the fact of descent. The effect is to try to turn the clock back to a time when immutable versus mutable species was actually a serious debate, a period when Owen and Darwin might have been thought evenly matched for a while. Like Prince Albert, Owen might have finished up gold-plated and Darwin relegated to a back room somewhere in Dry Storeroom No. 1 if only the facts had turned out differently. History has been kinder to Owen than might have been the case. He is recognized as one of the leading anatomists, an outstanding scientific organizer, and instigator of a great museum, even if his dreams for it were transmuted.
The marble statue of Charles Darwin, in wise old age.
Seated statue of Charles Darwin. Photo © Natural History Museum, London.
The hidden rationale behind the displays in any natural history museum I can call to mind is evolutionary, at least as a kind of organizing principle. It does not have to be like that. I can easily imagine an interesting museum in which organisms were arranged by size or colour, or by their utility to mankind. Storage of all the specimens behind the scenes is an entirely different matter, for that has to be systematic. I understand that there is a now a Creation Museum in Kentucky. Its own creators doubtless regard it as a ‘balance’ to all those pesky ‘evolutionary’ museums. It is interesting that the embodiment of respectability for an idea is still a museum, as if a Museum of Falsehoods were a theoretical impossibility. I look forward to a Museum of the Flat Earth, as a counterbalance to all those oblate spheroid enthusiasts.
The Natural History Museum is just one of many in the United Kingdom, and its story could be matched in almost any European country or in North America. The great proliferation of museums in the nineteenth century was a product of the marriage of the exhibition as a way of awakening intelligent interest in the visitor with the growth of collections that was associated with empire and middle-class affluence. Attendance at museums was as much associated with moral improvement as with explanation of the human or natural world. Museums grew up everywhere, as a kind of symbol of seriousness. Universities founded their own reference collections, some of which grew and prospered. Cambridge University has a collection for almost every science department, and Oxford University acquired one of the most beautiful museums of natural history in the world. In some ways, it is a small version of the London museum, but lighter and airier inside, less cathedral, more market place. Large towns needed a museum to celebrate their prosperity, and this period of unrivalled industrial growth meant that there were many new fortunes that sought relief in the purchase of collections. Gentlemen needed ‘cabinets’. An interest in natural history was almost as respectable as an interest in slaughtering wild animals. Our mammal collections show that the two interests were far from incompatible, and that an African or Indian ‘shoot’ could easily become a collection. Scotland was redoubtable in the eighteenth and early nineteenth centuries as an intellectual centre, so it is no surprise to find that the Hunterian Museum in Glasgow and the Royal Scottish Museum in Edinburgh both have wonderful collections. Wealthy individuals began to realize that a certain kind of immortality could be ensured by endowing collections in their name, and that this was a rather more tangible result than the prospects in the afterlife. One thinks of the Carnegie Museum in Pittsburgh. The upshot of all this was an explosion in the number of museums paralleling the growth in the numbers of Literary and Philosophical Societies. Nor was this activity confined to the middle classes, as Jonathan Rose has explained in his Intellectual Life of the British Working Classes. No, there was general enthusiasm in most social classes for the life of the mind and the excitement of the new exhibit.
And in the case of Britain this enthusiasm was coupled with the expansion of the Empire. The rights and wrongs have been debated, but it cannot be questioned that the British thought they had both a right and a duty to collect, and then collect some more when abroad in the Empire; and then to send the contents of their collections back home – for keeps. In the eighteenth century, the prospect was for plants of ‘utility and virtue’ as Sir Joseph Banks had said. The market potential was very explicitly built into the purpose of collections. Banks’ collections made on the Captain Cook voyage in Endeavour between 1768 and 1771 were one of the glorious foundation stones on which the Natural History Museum was built. But in the nineteenth century there was an increasing awareness that the study of plants and animals had a value in itself, that indeed there was a duty to inventory the glories and variety of the Empire’s realms; this was an impulse carried forward into the twentieth century, at least until the liberation of the ‘colonies’. Many of the collectors were amateurs in the best sense – intelligent men and women posted to India or Australia, or another of Britain’s many dominions, with time enough to make collections. This was no doubt motivated in some expatriates by the need to alleviate the boredom of duties carried out far from home; others may have made natural history collecting part of a wider programme of exploration. Terrestrial snails were sent to the Natural History Museum by the splendidly named Henry Haversham Godwin-Austen from India, where, among other things, he surveyed the world’s second highest mountain, K2 or Mount Godwin-Austen. Many collectors were talented artists, and women, in particular, were often trained in the skills of watercolour painting. Colours in life could be accurately recorded, even if the collecting process dimmed the original. Then, too, the postal system of the Empire was very efficient, so that collectors could receive encouragement and requests for more specimens from the appropriate Keeper or curator at a museum. From some parts of the world, such as Burma, it was easier to communicate then than it is now.
Many private collections made by moneyed individuals eventually found their way into the national collections by bequest or donation. I might mention as one example the collection of Allan Octavian Hume from the Indian Empire acquired in 1885, with 63,000 bird skins, 19,000 eggs and, as an afterthought, 371 mammals. Or there is the famous Lepidoptera (butterfly and moth) collection, comprising some hundred thousand specimens, left as a bequest by Edward Meyrick in 1938, the product of his lifetime’s learning and publication. Some collections were purchased; Hugh Cuming’s collection of shells was bought in 1866 for the appreciable sum for the time of £6,000, and a special grant was made from Parliament to buy it. It comprised 82,992 specimens. That is more than a dozen for a pound, which actually sounds quite reasonable. Overall, the collections grew apace, mostly filling up those cabinets behind the scenes, so that the general public would have been unaware of the increase. In terms of sheer numbers, the entomologists always win. According to William T. Stearn the insect collections had grown from 2,250,000 specimens in 1912 to some 22,500,000 in 1980. For the whole Natural History Museum, the latest figure is eighty million specimens. Such a number is quite incomprehensible as a quantity. Who could say if a huge pile of wheat in front of them comprised a million, ten million or eighty million grains? We simply do not see large numbers that precisely. Perhaps the more meaningful image is that of the ranges of drawers I saw stretching away into the distance when I explored the far reaches of the Entomology Department all those years ago. There was a vision of the scale of life, shelves and shelves of it, stretching away apparently for ever. That is the extent of our responsibilities.
Making known the zoological treasures of Empire: the cover of Allan Octavian Hume’s journal Stray Feathers.
Title page of Stray Feathers, A Journal of Ornithology for India and its Dependencies, Allan Octavian Hume, Vol. 2, (1874).
One of the few things one can admire about the British Empire was its propensity to make museums and botanical gardens. A few years ago, I visited the Indian Museum in Calcutta, another huge and serious building in which the artefacts of the subcontinent were housed. The old Indian Geological Survey was nearby, and there were preserved trilobite specimens collected at the end of the nineteenth century, still in their original cardboard boxes. It was as if the whole place had been preserved perfectly since the British left, a kind of fossilized museum. The curation system still worked, although the twenty-first century had yet to impact on the organization. The same old typewriters were still at the deal desks as they had been in 1947. A clerk arrived at 10 a.m. every day and dusted them off with a feather duster, and then proceeded to do little visible work for the rest of the day. Flies buzzed in the sleepy heat of the afternoon. In the same city was a Botanical Garden, magnificent in decay. The old pavilions had literally gone to seed. Once formal flowerbeds were now overrun with native creepers. It was sad to see a system that had once worked so well fallen into desuetude. There were even snakes in the grass. The banyan tree had grown into the biggest in the world, or so it was claimed, with its many branches propped up by the columns of its aerial roots, so that this wholly natural structure looked like the great mosque of the Mesquite in Córdoba. I hope that when India becomes rich on its own account a little money will be spared to restore the Calcutta Botanical Garden. I had seen its well-cared-for equivalents in Christchurch, New Zealand (see colour plate 4 (#litres_trial_promo)), and in Sydney, Australia, both now grown to splendid maturity, and both worthy heirs to Kew Gardens in London. I like the thought of early colonists listing the creation of a botanical garden and museum as one of the earliest necessities, a badge of civilization. One could argue that this particular idea still has currency, even if many of the other colonial ideals have not withstood the scrutiny of history. It certainly indicates that the nineteenth-century administrators took plants and collections seriously. It is of a piece with the growth of museums and civic gardens in nearly every big town in the home country, and with the great exercise in the systematization of nature that prompted all those earnest contributions to the collections of the Natural History Museum in London, and its equivalents around the world. Nature must evidently be known and named, no less than its beauty appreciated.
Perhaps those colonial pioneers dreamed that the biological world would be described before the dawn of the twentieth century. If so, their dream went unfulfilled; that century came and went and still the inventory of nature was far from complete. I have mentioned already how the labour of making all the species known is still in progress in the twenty-first century. It will not be completed at the end of it, because of the sheer size of the task. We shall see below how modern molecular techniques might provide a shorthand way of speeding up identification. The problem now has an added urgency because of the changes, mostly destructive, that mankind is foisting on the environment. Who can predict whether whole ecosystems will be pushed to extinction as a result of global warming? There are so many species out there that have never been named and described, like those I mentioned in the deep sea. The Times reported on 27 June 2006 that an average of three new species of animals and/or plants had been discovered in Borneo for every month of the preceding decade – and this in a part of the world where forest has been reduced by 25 per cent since the mid-1980s. Every species on Earth has a biography and each one is fascinating in its own way. There may be biologies in the deep sea about which we know nothing. Some of them may be useful to mankind in medicine, or in dealing with extreme conditions as we begin to stretch our metaphorical legs to climb to the stars. Who knows? If we allow species to disappear before they have a chance to tell us about themselves it will be a tragedy to add to the many that our species has already inflicted on the world. The first stage towards understanding is naming – to recognize that this creature before us is different from another already known. I believe we do not have a moral right to imperil the continuation of any species. Who are we, one species among so many, to obliterate the work of millions of years of evolution? Are we like the Greek gods acting on whimsy? Unfortunately, it is difficult to persuade everybody of this moral position. It appears on few political manifestos, except as a kind of harmless truism, vaguely akin to ‘we must be kind to pretty furry things’. It is so much more important than that. I don’t want the only record of a species to be on a video archive, or one of those gloomy, pallid faces peering out of a jar in the Spirit Collections.
Now that it is clear that natural history museums have an increasingly important role in a world whose biodiversity is threatened, I should perhaps explain the nuts and bolts of naming animals and plants. Readers who are gardeners or ornithologists will be accustomed to calling their plants or birds by scientific names. These names provide a common language for all biologists around the world, because they are the official name, the agreed nomenclature. If the name Larus ridibundus is used by a Japanese, an American or even an inhabitant of the Philippines, it is the same bird species that is being identified, regardless of the local name; ‘black-headed gull’ just happens to be our British local name for this particular bird, but few Englishmen would know what the Japanese might call it. Different gull species would be just as precisely specified by their scientific names: Larus argentatus (our herring gull), Larus atricilla (laughing gull to an Australian) and so on. Plants can have many different vernacular names for the same species, even within the same country. In his magisterial Flora Britannica Richard Mabey tells us that Cow Parsley is known as Queen Anne’s lace, kex, kecksie, mummy die, grandpa’s pepper, badman’s oatmeal, blackman’s tobacco and rabbit meat. Anthriscus sylvestris may lack the charm of these local names, but it means the same to all interlocutors, regardless of their origin. The scientific name for a species has to be a unique two words, or binomial, so it differs from human names in this respect, where there is no limit to the number of John Smiths. The name has two parts: first, the genus (or generic) name which is invariably capitalized; the second, the species (or specific) name, which is never capitalized even if it obviously named after a person – as in johnsmithi. The latter is a convention, as is the italicization of the scientific name, which readily allows recognition of a scientific appellation in a sheet of printed text. When the same generic name appears in a list, it is customary to abbreviate it to the initial letter, as, for example, in remarking that a collection of birds’ eggs included examples of those of Larus ridibundus, L. atricilla and L. argentatus.
If no two animals may have the same scientific name, neither may any two plants. I do not believe it is against the rules to use the same name for a plant and an animal since there is little chance of confusing an ant with a liana. I have toyed with the idea of naming a trilobite Chrysanthemum just to be mischievous. A unit of classification is a taxon (the plural is taxa), and that is why the business of naming them is taxonomy. Scientific names have a long tradition of taking Latin or Greek form. This goes back to the days when scientific communication was in Latin, as the language understood by the intellectual classes across Europe. In the early eighteenth century descriptions and names of plants and animals were often rather unwieldy slabs of Latin. The present simple system of naming and classifying animals and plants was developed in the eighteenth century by the Swede, Carl von Linné, who is himself nearly always latinized to Linnaeus: he it was who showed the utility of the binomial to characterize the species of the living world.
Linnaeus’ tercentenary was in 2007. As part of the celebrations I was asked to reply to a speech given at the Linnean Society of London by His Imperial Majesty Emperor Akihito of Japan. Thanks to Linnaeus, His Majesty was able to talk to his fellow ichthyologists about his favorite organisms, small fishes called gobies. I was told that the trees in the Imperial Garden are labelled with their scientific names. We all understood one another, and everyone smiled. Linnaeus worked in his maturity in the charming and ancient city of Uppsala; his system triumphed because of its utility and comprehensiveness. He developed his ideas in plant classification as a young man during travels to Lappland – then a daring undertaking. A quirky portrait of him dressed in Lappish robes was actually painted in Amsterdam a few years later, but it does seem that, like Darwin on The Beagle, a youthful adventure set him on the course to greatness. His classification of plants was based on such features as counting the number of stamens – it was a sexual system. Some young ladies were forbidden to study it because it might bring a blush to their delicate cheeks. Linnaeus’ mission to classify knew no bounds: he moved from plants to animals. Deus crevait, Linnaeus disposuit (God created, Linnaeus organized) served as his motto. He distributed his binomials far and wide. The Botanical Garden he laid out in Uppsala, with neat beds arranged according to his system, is still in good order. It ought to be one of the holy places for scientists to visit. Even if the simple sexual system has now been superseded the legacy of the names lives on. Linnaeus’ higher and more inclusive levels of organizing organisms into Order and Class and Kingdom are also still used as part of the hierarchy of the system. The labels on the cupboards that I passed in my peripatetic passage around the Natural History Museum were mostly family names, and the family originated as a unit of classification slightly later.* (#litres_trial_promo) Inside a given cupboard the curator might have placed a number of species belonging to several genera, all embraced by the family whose name is on the door. It is, if you like, a sophisticated filing system, and if you have millions of specimens the necessity of a filing system that works is patently obvious. I will leave until later in this chapter the question of what the filing system actually means in terms of evolution and ancestry, since Linnaeus lived and worked in a pre-Darwinian world, although I should say that like all taxonomists he used the features of the plant or animal concerned as the basis for his classification. The convention of using Latin and Greek for names was easy work for the early taxonomists. Most of them had been educated in the classics, and they knew their way around mythology and literature. Quite soon a whole dictionary of gods, goddesses, nymphs and satyrs had been recruited to label the natural world, mostly as generic names. Daphne is a flowering shrub, Daphnia is a water flea; Daphne herself was a nymph pursued by Apollo, and changed into a bay tree, as always seemed to be happening in those days. The bay tree itself is Laurus nobilis, ‘noble’ because the aromatic leaves were used to crown the brows of heroes.
Like nobilis, species names often were, and still are, epithets describing some salient feature of the animal or plant in question. A very beautiful plant might be the species magnifica, a very ugly one the species horrida. The specific names can be much more complicated, produced by splicing several Latin words together, so that a species with bright green leaves might be viridifolia, or one with leaves resembling the skin of a crocodile crocodilifolia; this complexity is fortunate, since a very large number of names are needed to accommodate all the beetles. It is necessary for the describer to have at least some knowledge of the classical languages because of the rule that genera have gender – masculine, feminine or neuter – and the species name should therefore agree in gender with that of its genus. The suffix on a genus -us is masculine and requires a matching -us on the species. The suffix -a is feminine, so that a commonly cultivated shrub originating from South America is Fuchsia magellanica and not Fuchsia magellanicus; -um is a neutral ending. Incidentally, Fuchsia is named after a famous herbalist, Leonhard Fuchs, who illustrated plants most decoratively two centuries before Linnaeus, and although Fuchs was evidently male, the genus named for him is female. This paradoxical practice is very common in botany: the well-known names Forsythia, Buddleia and Sequoia are comparable cases. To add a little Gormenghast to the nomenclatural mixture, Fuchsia (not italicized) was a decidedly female character in Mervyn Peake’s Gothic extravaganza, thus completing Fuchs’ sexual transmutation on the human scale. The epithet magellanica is a reference to the occurrence of the shrub as far south as the Straits of Magellan rather than a direct reference to the great explorer. However, as with Fuchs, it is quite common to name a plant or animal genus or species after somebody, often to honour his or her contribution to the field of study. I have done it myself for people who have collected specimens and then presented them to the Museum collections, or for professors who deserve recognition for all their hard work. It confers a modest piece of immortality. In the case of a species one needs to add a genitive suffix – as in Fuchsia johnsmithi – to show that this is John Smith’s species of Fuchsia. There are a few named forteyi species of fossil, all of them remarkably handsome examples of their kind. I should add that it is not regarded as good form to name a species after oneself; somebody else has to do it; modesty forbids after all. Nor is it permitted to cause offence by naming a creature johnsmithi after John Smith while stating that it is the most unattractive member of the genus. I have to say that Linnaeus himself did not follow this prescription, and named a useless weed Siegesbeckia after one of his enemies.
Humour is a delicate matter in nomenclature. The clam genus Abra is crying out to be married with the species name cadabra; and so it was in a species named by Eames and Wilkins in 1957: Abra cadabra, a very satisfactory touch of humour. However, a subsequent authority decided that the species cadabra did not, after all, belong in Abra – so it was moved to another genus, Theora, and there is nothing very entertaining about Theora cadabra. This kind of decision happens all the time in systematic work, as a subsequent author concludes from careful study that a given species is better included in a genus different from the one to which it was originally assigned. Effectively, this moves the species from one drawer in the collections to another. Old views are dropped and new combinations of names have to be learned; this process is known as revision.
The generously endowed fossil ostracode Colymbosathon ecplecticos causes a sensation in the Sun.
Fossil ostracode Colymbosathon ecplecticos. Photo © David Siveter. Article © The Sun.
Almost as good a pun as the Abra example is one of the numerous carabid beetles I mentioned above – Agra phobia. But my favourite remains the plant bugs described by one G. W. Kirkaldy in 1904. These genera all had the Greek suffix -chisme, pronounced ‘kiss me’. Kirkaldy managed to celebrate all the female objects of his affection by adding the appropriate prefix: Polychisme, Marichisme, Dollichisme and so on (there were rather a lot of them, apparently). Sexual innuendo is evidently irresistible to some taxonomists. It can be more blatant. Professor David Siveter of Leicester University is an expert on small crustaceans called ostracodes. In 2003 he and his colleagues published a paper on a magnificently preserved new fossil genus and species from the Silurian of England, which were some 425 million years old, under the resounding name Colymbosathon ecplecticos. If I might be forgiven for returning to the territory of ‘Biggus Dickus’, the remarkable fact about this ostracode was the size of its fossilized penis: if we translate the Greek, this Silurian species is ‘swimmer with astoundingly large penis’. Oddly enough, this attracted the attention of the press in a way that few new species have ever done. The Sun, always the leader in tastefulness, featured the story under the banner headline ‘OLD TODGER’; the Guardian was hardly less brazen with ‘Well hung geologist’. I doubt whether Science, the distinguished magazine that published the original article, has previously been featured in the pages of the Sun.
To the scientific name is added the namer: Abra cadabra Eames and Wilkins, 1957, or Colymbosathon ecplecticos Siveter et al. 2003. This is so that readers will know who first described the organism concerned, and when. It is remarkable how many plants familiar to Europeans were named first by Linnaeus – certainly almost all the common flowering plants. Botanists like their authors to be abbreviated, and Linnaeus is abbreviated to a bald ‘L.’ – hence, bloody cranesbill is Geranium sanguineum L. The works of Linnaeus are taken as the starting point for all modern scientific names, and everything published earlier is arbitrarily neglected. The beginning of modern nomenclature for plants is his Species Plantarum of 1753, and for animals the tenth edition of Systema Naturae, 1758. Fungi are different, since Linnaeus did not have much to say about them. The greatest early mycological figure, the ‘Linnaeus of mushrooms’, was another Swede called Elias Fries, who seemed to have an almost uncanny memory for these most fleeting ‘vegetable productions of nature’; in fact, modern molecular studies have shown that fungi are not really vegetables at all. His great work published between 1821 and 1832 is a conscious homage to Linnaeus, the Systema Mycologicum, and hence mushroom names go back to 1821, although Fries is said to ‘validate’ certain still earlier names, such as that for the familiar fly agaric, Amanita muscaria, the archetypal red mushroom with white ‘spots’, which Linnaeus had already included in his remit. Quite why Sweden, and in particular the University of Uppsala, should have had such a grip of the system of nature is an interesting question. I went to see Linnaeus’ farmhouse outside Uppsala at Hammarby to find out if it offered any clues. It is a simple wooden building, now painted maroon, with neat white square windows, no different from a hundred others in the more agricultural part of Sweden – sensible, four square and with a proper feeling for place. Maybe the clue was in the very modesty of the structure; nothing showy, just a monument to hard and consistent work – farmers’ virtues, Swedish virtues, Lutheran seriousness.
So far I have said rather a lot about names, but not much about science. The real business of taxonomy is to look closely at the animal or plant in question to assess its features, the business of identification. Only then can you identify a new and unnamed species, or establish whether a previous observer was mistaken about its systematic position. There is no way of generalizing this process, since every different kind of animal or plant is a distinct proposition. If you are ‘spider man’ you don’t climb up walls to save the world as we know it, but you do know a tremendous amount about spider genitalia, because that is the best feature by which to recognize a species. The fern woman will look at the spore capsules on the back of the fronds, and appreciate subtle difference in the way the fronds are subdivided. Flowers and leaves will be the traditional bailiwick of the botanist; spores and microscopic cellular structures on the gill edge will be the province of the fungus man. A crustacean expert will peruse the finest details of the legs and the antennae of his object of study. A mollusc specialist might appraise the colour and ornament of a marine snail, while a lepidopterist will be as familiar with the speckles and dappling of a butterfly wing as he would be with the faces of his own family. One lepidopterist I knew was actually rather more aware of the former than he was of the latter. An ornithologist might listen to songs, spotting their individuality at species or racial level, but then so will an expert on cicadas or bats. Many specialists will take themselves off to the electron microscope, which will afford crisp photographs of the tiniest of organs or ornament on the smallest of animals: bryozoans (‘sea mats’) stand revealed as decorators as virtuosic as Islamic ceramicists; a tiny mite encrusted with horns and growths as Gothic as an extra in a Dracula movie; the cells of a parasite beautifully embroidered with the equipment they need to carry out their depredations; the teeth – radula – of a mollusc as distinctive as a rack of stalagmites. The palaeontologist will have fewer details at his disposal, and so will be obliged to read as much as he can from the testimony of bones or shells – the wonderfully symmetric test of a sea urchin, the calcite exoskeleton of a trilobite, the tiny pollen grains of a plant that has long vanished from the earth.
The next stage is the library. Although memory is important in identifying specimens, sooner or later it must be checked against the printed record. This is the point where the scientist takes himself or herself off to the journals and monographs, wherein will be found descriptions and synopses of species related to the one under the microscope. The appropriate number of the journal will be found in a catalogue, nowadays on a computer, and then the hunt around the miles of shelves will begin. If a new species is to be named it is important to check that it has not been described before, no matter how obscure the book or paper in which it might have first appeared. If an author is unlucky enough to miss an earlier name for an organism then his own will be doomed, for there is an internationally accepted rule that says that the first published name has priority. An unnecessary younger name then disappears into what is termed synonymy. We have already seen that the valid literature goes back into the eighteenth and early nineteenth centuries, so it is not uncommon to find that a species has already been described somewhere else. A great library like that of the Natural History Museum is an enormous asset, because it holds all the old literature. Most university libraries do not. In this regard, systematic science is quite different from physics or chemistry or physiology, subjects in which old literature rapidly becomes obsolete. Most scientists will not cite references dating back more than a decade, and so they will be unfamiliar with the scholarly pleasures of browsing through old, leather-bound tomes. It is also a fact that old literature in taxonomy is often as beautifully illustrated as any modern production, particularly the plants, for the drawings of many of the botanical artists of the eighteenth and nineteenth centuries have never been surpassed. Old is not necessarily out of date. Some of my white-coated scientific friends find something amusingly antiquarian about this emphasis on the past, perhaps an image of pince-nez perched on aquiline noses snuffling around in ancient Serbian publications. It is only a little bit true. Most specialists build up personal libraries, and therefore save their legs, and time, in pounding the library floor. The internet has become a wonderful resource for accessing literature, which can now be posted well beyond the confines of the national libraries. There might come a time when all those miles of shelves will be available online from the comfort of home, although I somewhat sentimentally believe that there is an added value in the physical contact with old books. Whatever circumstances arise in future, the paper originals must be preserved and conserved, even though librarians roll their eyes at the sheer quantity of book storage, because cyberspace is not necessarily truthful, and the web can easily become a web of deceit.
The scanning electron microscope reveals countless unexpected details of taxonomic use. Two views of an orobatid mite larva Archegozetes that would fit onto a pinhead: a dorsal view of whole animal and a detail of the head region from below.
Orobatid mite larva Archegozetes. Photo © Richard Thomas.
It will be problematic indeed to dispense with libraries. At the moment there is a requirement that publications proposing new species should be deposited in one of the copyright libraries – which include our library in London, and the Library of Congress in Washington, and their French, German and Russian equivalents. This is some safeguard against rogue publications and authors setting up new species of animals or plants on spurious grounds. The other safeguard is the system of scientific peer refereeing through which papers submitted to most journals are supposed to pass. An independent reader anonymously says whether the potential publication will pass scientific muster. Neither is foolproof: self-published books can be sent to the libraries and refereeing can be bypassed or inefficient. The eccentric Scottish geologist Archie Lamont set up his own journal, the Scottish Journal of Science, which he published from his private cottage in the small village of Carlops. He could just about fulfil the conditions for valid publication, and he set up all kinds of odd-sounding genera of Cambrian trilobites with Scottish names, like Robroyia and Cealgach on the basis of miserable scraps. Tails might as well be figured as heads in these works. It has taken years to sort out the taxonomic mess. Almost any other group of organisms will potentially tell a similar tale. Mollusc shells are particularly popular, and the most beautiful of molluscs are unusual snails known as cowries. They show a wonderful and seemingly endless variety of colour patterns, speckled and painted in myriad ways. It is perhaps not surprising that amateur conchologists think they have discovered a new species, and seek the immortality acquired through naming one in publications for their fellow enthusiasts. Many of these claims do not bear close scrutiny, for pigment speckling varies naturally within populations, and not every pattern has a biological reality as a species characteristic. But to sort out the true situation requires all the facilities that a reference library has to offer, ungrateful work much of it, pernickety and irritating. All this labour may eventually be reflected in the small print of a list of synonyms; work at the coalface of taxonomy often lacks glamour.
So now our specialist has carefully looked through the pages of a couple of dozen monographs and papers, comparing illustrations of many species with the specimen in front of him. Piles of old books and reprints of papers litter the office floor. He is convinced that the species he is looking at has never been seen before, based on his wide experience of ‘his’ organisms. It is a new species. He now needs to give it a technical description, illustrate it accurately, give it a new name and then get it published. He thinks that it is an exceptionally wonderful example of its genus, so he decides on the specific name mirabilis (Latin, ‘wonderful’, ‘marvellous’). He checks through all the publications before him; sadly, he finds that a Lithuanian Jesuit had already used the epithet mirabilis for a species of the same genus in 1896 in an obscure journal published in Vilnius; this species name is therefore unavailable, and he must find another one. Cursing slightly, he reaches for the Latin dictionary and finds repanda, ‘sought after’, instead; good – this one has never been used before, and it will suffice. The next few days are spent in writing an accurate description of the new species, in language as dry as a James Bond martini, with a differential diagnosis saying how it differs from all species known previously. The language is a disguise for the excitement of finding a species new to science, a formal cover-up, or an epistemological stiff upper lip. He might prepare careful drawings under the camera lucida, or supplement his accurate but slightly soulless drawings with photographs prepared by the Museum’s skilful studio photographers.
The new species is almost ready to go to publication, but before it can be a valid addition to biodiversity some other important criteria have to be fulfilled. A specimen from the collection has to be selected as the ‘type specimen’; this is a unique specimen upon which the identity of the new species must ultimately rest. It is known technically as the holotype in animal taxonomy, and to be valid must be given an official museum number unique to it. Other specimens in the original collection identified by the author are paratypes. Together, these specimens constitute the type collection – the material that provides the material basis for a species’ identity in perpetuity: serious stuff. The type specimens are the scientific treasures behind the scenes of the Natural History Museum, a register of biodiversity, held for future generations. They are the ground truth for species in the natural world. Scientists who wish to know whether they are really dealing with the same species will, in the end, have to refer to the types for a definitive opinion. Is this weed that has suddenly taken over crop fields in South America a European invader? Is this fossil ammonite the same as one described in the early nineteenth century from Dorset – and hence are the rocks from which it came likely to be the same age? Is this fly that is plaguing cattle in Namibia the same as one from Libya, and if so how did it get there? Ultimately, the resolution of such questions means that the original specimens have to be examined. Once again, the web is making some difference to how this works out in practice, since it is possible to visit collections in virtual reality. But many fine details – like tiny hairs and microscopic characters – will probably never be accessible over the web. Then there are the sheer numbers involved. A recent estimate puts the London museums’ holdings of types at about 670,000; it would be a vast undertaking to put them all online. Originally, the Natural History Museum hung on to its types as firmly as the original BM hangs on to the Elgin Marbles. But now in more enlightened times type specimens can travel to recognized sister institutions and bona fide workers. And of course the latter are always welcome as visitors to the vaults. This process probably helps more than anything else in recognizing synonyms, and improving the global standard of taxonomy. So the spoils of Empire have now become a global resource, one that should be recognized by all international bodies concerned with biodiversity.
Scientists deposit their type specimens in the Natural History Museum, or its equivalents elsewhere in the world, because they know that the specimens have been properly curated and cared for there, and should be looked after for future generations. Hence the collection builds steadily in importance as a reference base. There are plenty of examples elsewhere where type specimens have not been recognized for what they were. There are universities that have supported a well-known scholar, and when he or she dies the collections made by the scientist have been assigned to a dusty corner and forgotten. I know of an example where type specimens of fossil ammonites have been rescued from a skip; they might have finished up in the foundations of a building rather than as the foundation of a species. Some type specimens are historically celebrated. The duck-billed platypus (Ornithorhynchos) is a bizarre Australian mammal, which is famous for laying eggs and having mouthparts like a shoveller duck, not to mention a tail like a beaver. When a specimen was brought to Europe in 1798 it was thought to be a fake, a confection stitched together from different animals by a taxidermist with a perverse or mischievous sense of humour, for it was an animal that should by rights not exist in a well-ordered world. A careful description of the type material proved that the antipodean puzzle really was what it purported to be. We are now quite familiar with its living reality thanks to wildlife photography of the platypus in its natural habitat, where it uses that curious bill to sense small animals on stream bottoms, and the tail to help it swim – not so much an unnatural impossibility as a highly evolved specialist that retains some ancient characteristics. But the type specimen still resides in the collections of the Natural History Museum as a slightly scruffy skin, a veteran of the triumph of science over disbelief. Most types are altogether less famous, and much less conspicuous. Holotypes in the Palaeontology Department are marked only by a modest green spot attached to the rock. Their presence is known only to a small number of specialists and curators. But their importance will not diminish as long as our species pays any attention at all to fellow inhabitants of our planet. The types are still only a small part of the collections; the rest includes comparative material of many more species, or collections made from inaccessible parts of the world, or collections associated with a distinguished individual; so many riches contribute to the archive of the natural world.
The type specimen of the duck-billed platypus (Ornithorhynchus anatinus). This animal was not believed to be real when it was first described.
Duck-billed platypus. Photo © Natural History Museum, London.
The taxonomic process as I have described it would certainly have applied at the time I first nosed my way cautiously around the maze of offices and corridors in the Natural History Museum. I still believe today in the primacy of collections and specimens – they don’t go out of fashion, because they are preserved to outlive any passing phase of epistemology. However, it would be surprising if there had not been changes in scientific practice and theory over the last decades, if only because science always moves on. I deliberately concentrated on species above, because that basic unit has retained its central role in systematics, no matter how technique and theory have changed elsewhere. Species are not merely specious.
The most important change in the scientific firmament was the appearance of molecular techniques. The possibility of sequencing genes followed upon the unravelling of the structure of DNA – and now has reached new heights after the decoding of entire genomes, including that of our own species. What began as a major technical challenge is now almost entirely routine, and every research institute worth its salt, including the Natural History Museum, has a molecular biology laboratory, staffed by scientists of the white-coated variety, slaving away with test tubes in front of highly sterile machines. Nowadays, an organism must reveal its secrets down to the molecules in its DNA or RNA. Gene sequences provide a whole plethora of characters to add to the traditional morphology – something to challenge the hairs on legs, spines on shells, pattern of bones or structure of flowers. Because the genome is almost unimaginably huge, the potential for information locked in its sequences of bases is theoretically almost endless. It is small wonder that there has been a boom in the employment of molecular biologists at the expense of traditional experts on groups of organisms.
More than twenty years on from the appearance of these techniques it is possible to see just how many questions can now be tackled which were previously beyond reach. Many people have used the obvious pun ‘designer genes’ before, but it is not a bad phrase to summarize what scientists actually do with the vastness of the genome. They use different parts of it for different purposes. If they have been curated appropriately, pieces of type specimens can even be fed into the DNA factory, thanks to a technique known as PCR that ‘magnifies’ sequence information from tiny pieces of tissue. There is, of course, much variation in the genome within a species. Some variation is at the level of the individual – hence the possibility of ‘nailing’ a criminal for an offence using stored samples such as blood or semen years after a deed has been committed. The gene sequences in question identify a particular person beyond doubt, like a fingerprint. Other changes in gene sequences are conserved for slightly longer periods of time; sections of DNA called microsatellites have high rates of mutation, which makes them ideal for studies within the historical time span and within species – for example, in tracing movements of human populations around the world. Other parts of the genome change still more slowly, and yield sequences that are of particular use in recognizing species – we will come back to these again, because they are of special importance in taxonomy. Other parts of the genome are generally conserved, which means they accumulate changes only very slowly, over millions of years, or even longer. Some of these genes are important in the functioning of any organism – they include genes that encode proteins, for example. Or there is the RNA of the cell’s ‘powerhouse’ organelle, the mitochondrion, which was one of the first molecules of this kind to be completely sequenced. Such slowly changing genes and sequences allow the scientist to ‘see’ backwards in time to the divergence of major lines of evolution, to examine relationships between different groups of organisms that might previously only have been investigated by the palaeontologist delving deep in the fossil record. To say that these discoveries had a profound effect on systematics would be a considerable understatement: it provided a whole new way of looking at the natural world. There are even genes that could potentially ‘see’ the separation of the major designs of animals and plants hundreds – even thousands – of millions of years ago. In 1991 great surprise greeted the discovery that the sequence of the elongation factor gene in the nematode worm Coenorhabditis elegans was more than 80 per cent similar to that in a mammal; here was common ancestry writ large. Some genes were evidently so deep-seated that they continued to do their work over a timescale of many, many millions of years. Such evidence proved beyond question that we are one with the worm and the bacterium.
The small nematode ‘worm’ Coenorhabditis elegans – so important in working out the genetics of all animals
Nematode worm. Coenorhabditis elegams. Photo © Phototake Inc./ Alamy.
Evidence from molecules was quite quickly incorporated into the intellectual armoury of the more forward-thinking systematists. For a while there was resistance in some quarters by experts who trusted implicitly their traditional characteristics for classification – colour, or hairs on legs, or behavioural patterns – and did not like the suggestions of new evolutionary relationships thrown up by molecular studies; and it was also true that in the early days some dubious conclusions were drawn from using the wrong ‘designer gene’ for a particular job. However, it was soon recognized that sequencing evidence could provide answers to questions that had been troubling systematists for years. I will give just one example. Edible truffles are subterranean fungi, belonging to the genus Tuber. There are several species, and gourmets dispute their relative merits. Tuber magnatum, the white truffle, which grows in Italy, commands the highest prices – up to about $5,000 a kilogram. It is the most expensive foodstuff in the world. The Périgord truffle, T. melanospermum, is mostly French in origin, and black rather than white. The warty summer truffle, T. aestivum, grows in England, but is less sought after, although it is the only one I have found in the wild. All are remarkable for having an extraordinary, and some would say irresistible, odour, which suggests a kind of mushroom/meat hybrid. This intense fragrance is imparted to oil or eggs, and indeed the simplest way to eat truffles is to use them to flavour an omelette, or to grate them finely over scrambled eggs. Pâté defois truffé is such stuff as gourmet dreams are made of. The edible properties of the truffle are not matched by their aesthetic ones, for most truffles look like some kind of knobbly animal excreta, which have been passed with not a little discomfort. They do not have to impress with their appearance, for it is the smell that matters. In the wild they grow close to the roots of trees, particularly oak (Quercus) and hazel (Corylus); they are one of a very large number of fungi that form a symbiotic relationship with the tree host, their mycelium enveloping or penetrating the roots in a so-called mycorrhiza. The host benefits from ions such as phosphate that the fungus can ‘hunt’ from the surrounding soil, while the fungus receives products of photosynthesis from its tree host in return. The problem for the fungus is how to spread its spores from underground and hence ensure its survival, and this is where the smell comes in. The spores are enclosed in chambers or fissures inside the truffle. Animals such as wild pigs find the smell of the truffle attractive, and will greedily grub up the fruit bodies. ‘Truffle pigs’ are trained to smell out the subterranean booty, which is removed from them before they can gobble it up. The spores will eventually pass out of the animal, unharmed, in droppings, having by then been dispersed widely from their point of origin. In rainforests in south-eastern Australia I have seen holes scratched by marsupial potoroos in search of truffles – very different creatures performing the same favour for a truffle on the other side of the world.
The author handles an edible black true truffle (Tuber) from Sardinia.
Edible black truffle. Photo © Jackie Fortey.
When the truffles were first recognized as fungi rather than some spontaneously generated freak of nature, it was thought that such curious productions comprised a single group of organisms – a reasonable assumption, one might think. They deserved one of Linnaeus’ high-level classification tags – an Order. But when microscopes came to be focussed on the tissues inside the truffle, where the spores were developing, an interesting discovery was made. Not all truffles were alike. Those that graced the tables of the rich and hedonistic showed features at the microscopic level like those of another gourmet treat, the morel (Morchella esculenta). In other, and more technical, words they were ascomycetes. These fungi bear their spores inside minute sacs or asci of the order of a tenth of a millimetre long – there are usually eight such spores, so the asci have a very typical microscopic appearance, rather like eggs wrapped in a sausage. However, some other truffles, for example a genus called Hysterangium, showed evidence that they were related instead to the gasteromycetes – the group of fungi that includes puffballs and stinkhorns. These are basidiomycetes, which carry their spores in an entirely different way from the ascomycetes; they are typically borne atop a special cell called a basidium, usually four spores in a loose cluster. The white mushrooms that fill vats in supermarkets are distantly related basidiomycetes, as are the majority of fungi that troop through the woods in autumn. The ascomycetes separated from the basidiomycetes very early in earth history, and certainly more than a billion years ago. It is preposterous to classify truffles together that have such different evolutionary origins – and so the ascus-bearing truffles were separated from the basidium-bearing truffles: so far, so sensible, and resulting in two Orders. For common names we now had ‘truffles’ and ‘false truffles’.
However, the story did not end there. From other microscopic hints there were suspicions that there were several origins for truffles in both the ascomycete group and the basidiomycete group. Truffles might have arisen repeatedly, on separate evolutionary trees, for all their superficial similarity. The closest relatives of a truffle might prove to be one of several different kinds of more normal-looking mushrooms and other fungi. The truffle shape, including its subterranean growth, is a specific adaptation – a mode of life, if you like. It was not so difficult to imagine a ‘truffle habit’ originating several times, because most fungi do indeed develop underground, and only later erupt at the surface. If development were somehow ‘arrested’ at the early stage – well, then you might have something like a truffle. The trouble is how could you pair the truffle with its closest-related mushroom, since there is so little general resemblance between them? This is where the molecular evidence should come into its own. The appropriate mushroom partner should, in principle, show more similar sequence patterns at the molecular level to its truffle relatives than it does to other truffles or indeed other mushrooms. So it has proved. Using the appropriate genomic tool, especially one known as ribosomal ITS (Internal Transcribed Spacer), the complexity of the origin of truffles has been demonstrated. It turns out that at least six different kinds of mushrooms – that is, the basidium-bearing kind – have become ‘truffleized’, to coin a term. To add to this there are several more origins of truffles of the ascus-bearing kind, of which the true truffle, Tuber, is one. Far from being a natural group of organisms, the truffles originated from numerous different fungi on several different occasions, and it all probably happened millions of years ago.
Why should anyone care about such apparently esoteric information? After all, most people can happily pass their lives without seeing a truffle of any kind, and who but an outstanding eccentric would spend hours carefully digging around in the litter under trees to find false truffles of the inedible kind? But then, who would guess that truffle evolution was crucial to the survival of several charming Australian marsupials? For the Australian group of truffles, including some placed in the genus Hydnangium, were also independently evolved in close association with Eucalyptus trees. These false truffles provide a prime foodstuff for bettongs and potoroos, which are delightful, nocturnal cat-sized animals that are now the focus of intensive conservation efforts. The more that is known of their requirements the more likely they are to survive in the twenty-first century. False truffles are as important to their continued existence as keeping them from the depredations of feral cats. So what might at first seem extraordinarily specialized information has links to those ‘pretty furry things’ after all; nature is seamless, its connections multifarious.
The truffle example also links back to where we started – the questions of taxonomy. Every time a truffle under examination turns out to be related to an entirely different mushroom, we can imagine a curator cursing quietly under his breath and moving the relevant preserved specimens to a different drawer. This is an extreme case of ‘revision’ – revisiting taxonomy. The point is that we expect classification systems, genera, families and so on in ascending order, to reflect fundamental resemblances between the species included in them. The species themselves are the units of this classification – at least they are if we have recognized them correctly – and they are the real things that get shifted around from one drawer to another. The genus or family whose name might be written on the drawer or cupboard is a theoretical concept, subject to change as science advances. As with the truffles, species may be added or taken away or moved around. The up-to-date taxonomist wants his classification concepts to square with modern views. For most such scientists this means that the species included in a genus, for example, should have descended from a common ancestor – that is, constitute what is known as a clade. The characters shared by the species in a genus – and nowadays these can be molecular characters as much as the traditional ‘hairs on legs’ – are what defines it, makes it a natural entity. Discover new characters and the concept of the genus may well change, and so will the species included within it. This results in changes in generic names for a given species that irritate many people, and particularly knowledgeable amateur scientists. ‘Why do they have to keep changing the names?’ is a common complaint. However, the contemporary investigator is obliged to seek out genera, or families, that are clades; the scientific method used in recognizing these groups is known as cladistics; and the whole business of examining relationships between organisms in this way is usually termed phylogenetic analysis, or simply phylogenetics. If names have to change as a result of careful reconsideration of species, well, that’s the price of progress. Much modern taxonomy is based upon computer analysis of relationships, where all the characters possessed by a group of organisms under study are allowed to fight it out until the ‘best’ arrangement of species is discovered, resulting in a diagram – a cladogram – showing how species relate to one another. The eventual classification is then drawn up directly from the cladogram. For example, several clades of species clustering together might be recognized as separate genera, and if these genera then cluster together in a more inclusive group this larger group might be the basis of a family.
This sounds technical, and so it is. Quite a few famous taxonomists are computer experts first, and lovers of organisms second. They think in algorithms rather than algae. They are mostly interested in animals and plants as experimental material for their classificatory computer programs. Their conversation tends to revolve around the statistical criteria for the support of one piece of the cladogram or another; an outsider hearing these people chatting might think she was overhearing an unknown Amazonian language. However, arcane though it might sound, the cladistic approach has made taxonomy much more of a science, and less dependent on the word of an authority alone. It provides a unifying method across the spectrum of organisms, from virus to vicuña, and can embrace all kinds of evidence, from the molecular to the anatomy of a blue whale. But it will be clear by now that it also makes problems for that Linnaean system of naming animals and plants. Linnaeus himself designed his ‘system of nature’ before the notion of evolution had gained currency. Some might have considered that the order of nature might be an expression of the mind of God alone: ‘he made them high and lowly, he ordered their estate’, as the hymn puts it. The idea that classification might involve notions of descent from a common ancestor was a subsequent introduction. The species as the unit of currency of classification was the only thing in common between these pre- and post-Darwinian worlds. And with the arrival of cladistics and molecular analysis the old Linnaean system might be seen to creak and groan under the stress of frequent changes in nomenclature – so much so that some scientists have tried to persuade their colleagues that the time has come to abandon the Linnaean binomial altogether. They want to replace it, or at least augment it, with something called the PhyloCode.
As this is written the PhyloCode is still undergoing its own evolution, and it might be premature to anticipate the outcome. Many critiques of the Linnaean system are surely correct. There is no consistency in the use of the ranks of the system between different kinds of organism; some parts of the natural world have small genera, other parts have large ones, and a family can be a very different concept from one worker to another. We already have an intuitive feel for this. Birds are finely divided into genera separated by tiny anatomical differences; on the other hand some genera of plants and fungi might include several hundred species. The attractive sea snail genus Conus includes at least six hundred species. The recognition of what makes a genus or family is partly a matter of tradition and taste. It is also undoubtedly true that there are not enough categories to recognize all the different levels of relatedness that a modern cladistic ‘phylogenetic tree’ can recognize, and nobody wants extra formal ranks with names like supersubfamilies or subsuperfamilies. There are quite enough names already.
PhyloCode is based entirely on cladistic phylogenies, and provides a system for naming clades – all of them. The old formal Linnaean categories above species level are abandoned. This is a rather revolutionary suggestion, to say the least, and it is not surprising that it has excited some strong opposition. To my mind the strict logic of the PhyloCode is beside the point. The most important thing about the current system of naming organisms is the common language it provides, not just to other systematists, but to the rest of the world – people like gardeners, or bird watchers, or fungus forayers. Very few members of this larger community know about the details of cladistic phylogenetic analysis, and I suspect that most of them want a meaningful label that they understand rather than reassurance that every category is quite the latest collection of good clades. The 250-year tradition since the great Swedish systematist does count for something. Many of the common categories that a naturalist will comfortably recognize are old Linnaean families. Think of lilies (Family Lilaceae) or daisies (Family Asteraceae) or crows (Family Corvidae). These turn out to be pretty good clades as well, meaning that the resemblance between the species in the families does indeed reflect descent from a common ancestor. In my experience more ‘difficult’ groups of organisms are often reanalysed time and again using the latest cladistic bells and whistles or new molecular evidence, and each new analysis is rather different from the last one. Nor is there any guarantee that the latest version is always the best. Potentially all these different analyses could be named under PhyloCode. In my view this would allow for just too many valid names, as each successive analyst sought to put his imprimatur on his briefly dominant hierarchy. But most important of all is a feeling that offends my democratic instincts, in that the systematization of nature would be even more in the hands of a coterie of specialists sitting in front of their computers than it is now. The binomial system has faults, but I suspect any new system would develop as many. The naming process would be taken away from the naturalists, nature lovers and intelligent laymen, at a time when there has never been so much pressure on the survival of species, or, indeed, on the survival of the taxonomists who know about fleas and carabids, trilobites and ammonites, grasses and orchids, or deep-sea worms. It is the survival of the biological world and of the basis of expertise that studies it that is the real concern of the twenty-first century. Names are the least of it.
3 (#ub4c63918-bd45-5513-b8e9-b6f50481fe6f)
Old Worlds (#ub4c63918-bd45-5513-b8e9-b6f50481fe6f)
It might seem an odd ambition to try to get everyone to pronounce a word correctly. But mine has always been to get the world to say ‘trilobite’ without fudging, and with a certain measure of understanding. My own mother was wont to say ‘troglodyte’, which at least has a certain prehistoric dimension, even if it refers to human cave dwellers rather than extinct arthropods several hundred million years older than humans. ‘Did you have a nice week with the troglodytes, dear?’ was one of her regular enquiries. A rather more common mispronunciation is ‘tribolites’ – an anagram of the correct word for sure, but probably an unconscious hommage to one of the humanoid tribes on Star Trek. ‘The tribolites have made it through the air lock, Captain. Permission to use phasers!’ I have no particular gripe against those who pronounce the word with a first syllable to rhyme with ‘thrill’, although I have always said ‘try-low-bites’ myself. The tri- part, of course, refers to the threefold division into which the calcareous carapaces of these animals are usually obviously divided lengthways – ‘three lobes’. On their underside, but rarely preserved, were many jointed legs of typical creepy-crawly kind, which reveal the trilobites to have been distant cousins of the crabs, butterflies, spiders and millipedes, with which they should be classified – in Linnaean terms, Phylum Arthropoda, Class Trilobita. For getting on for three hundred million years trilobites swarmed in the oceans, moulting and mating, and left behind their hard carapaces in the rocks as testimony to their former importance. At the moment we know something like five thousand genera of trilobites, and new species are being discovered entombed in ancient sediments such as limestones and shales. It is not surprising that they have been described as the ‘beetles of the Palaeozoic’. In fact, they still have a long way to go before they approach the beetles in biodiversity, but they are wonderfully varied creatures despite their simple ground plan, some with carapaces as smooth as beans, others like arthropodan porcupines, many as large as lobsters, yet others as tiny as water fleas. They evolved fast and are not uncommon fossils, so that they are useful in dating rocks – somebody who ‘knows his bugs’ should be able to say within a few minutes whether he is looking at Cambrian or Devonian examples; with more study the time zone can be narrowed further. Trilobites can tell about ancient climates, because different species lived in tropical as opposed to cool seas. They can tell us about vanished continents in distant eras, since different trilobites characterized different parts of the world. Study of apparently esoteric extinct animals can help us reconstruct the history of our planet.
A few years ago I wrote an account of recent discoveries of remarkable trilobites in the Devonian rocks of Morocco, dating from more than four hundred million years ago. I included an illustration of a bizarre creature that carried a trident on its head, as far as I know a unique structure in the whole animal kingdom. In 2000 this trilobite had no scientific name, although it was already possible to buy specimens of it over the internet. My colleague Pierre Morzadec named the trident-bearing genus Walliserops in 2001, commemorating a well-known Devonian specialist, Professor Otto Walliser of the University of Göttingen. In 2005 I went to Morocco to see the localities where these trilobites had been discovered. Brian Chatterton of the University of Alberta in Edmonton, Canada has been making a study of the trilobite sites in the Anti-Atlas for several years, and he invited me to join his field party that spring. Trilobites have become a major industry in the area around the small town of Erfoud, which had previously subsisted on a little bit of tourism to add to the small rewards provided by dates and agriculture. Mr Hammi was our guide and mentor; he is a helpful local Berber with no scientific training but a hugely intelligent ‘eye’ for a good trilobite. Since these trilobites have to be laboriously prepared out of the rock by hand, Hammi has made a successful family business with his brother supplying splendid specimens that have finished up in collections around the world. He has partly been equipped with microscopes and tools by an English fossil dealer from Cambridge, Brian Eberhardie, who also sold on some of the best examples. I might add that there are several other successful businesses producing cheap fakes. The localities in question are dotted over one of the most barren desert regions in which I have ever worked. It seems that the High Atlas Mountains steal all the water, leaving but a trickle for the Sahara side. But the barren hillsides of the Anti-Atlas provide perfect exposure of the rock formations. This is what geologists call ‘layer cake’ stratigraphy, where each stratum is horizontal, or gently tilted, so that climbing up a hillside from stratum to stratum is equivalent to climbing a staircase upwards through geological time. A productive layer can be traced over a long distance, or at least until a stretch of stony desert interrupts the outcrop. We went to an isolated hill called Zguilma, where trident trilobites had been collected over several years. There was actually a tree or two at the foot of the hill, tapped deep into some tiny source of water. Even in the cooler part of the year their shade was difficult to resist at three in the afternoon; in the summer it must have been impossible to work in the open.
The extraordinary sight that greeted us at Zguilma was a trilobite mine. The productive layer had been traced all along the bottom of the hillside and dug out in a series of trenches and pits, flanked by piles of debris. When Hammi arrived, muffled shouts in Arabic sounded from a hole, and out climbed a cadaverous old man with one or two yellow teeth displayed in a broad grin. He had been ten feet down in the hole in the full heat for several hours breaking hard limestone rocks. It was like being employed in Hades, with added hard labour. Mysteriously, the old man seemed cheerful enough. He was the beginning of the chain of discovery, for if he broke across one of the precious trilobites he would put both ‘halves’ on one side, and Hammi would pay him modestly for the find. Then it would be taken on to the laboratory for preparation, and if a good trilobite were extracted, might eventually fetch up at the Houston Fossil Show or some similar event carrying a price tag of several thousand dollars. The wizened old man seemed untroubled by the chain that led to Houston, and was doubtless unaware of the profit differential; he was glad of a break to share the sweet mint tea that is the social lubricant in the desert (‘Berber Whisky’ is a joke for the infidel). Every evening, in the incomparably still dusk that comes in the desert, we would all share tajine made from tough old bits of meat that had spent the day hanging on string between the branches of the token tree, mopped up with Moroccan bread cooked in warm embers. We had the same bread for breakfast spread with ‘La vache qui rit’ processed cheese. After a couple of weeks the diet began to pall. I have been allergic to laughing cows ever since.
Trilobite ‘mines’ in the Devonian strata of the desert in the Moroccan Anti-Atlas.
Trilobite mines in Morocco. Photo © Brian Chatterton.
Several years earlier I had persuaded the Natural History Museum to purchase from Brian Eberhardie another extraordinary trilobite from Zguilma. Now I had the chance to examine where it had come from for myself: evidently, it had emerged from some hellhole. The eyes on this animal were like those of no other trilobite, because they were elevated into a pair of near vertical towers, the outer side of which were lined with very conspicuous files of lenses. Sight was obviously at a premium for this particular species. The challenge was to work out how such flamboyant ‘peepers’ worked. One thing could not be disputed: this heavily armoured trilobite bearing its massive eyes must have lived on the sea floor. I then noticed something curious about the eyes: they had eyeshades overhanging them. Most trilobite eyes are rather strongly curved from top to bottom, with numerous tiny lenses and no eyeshade, but this trilobite had relatively few lenses in a vertical array, so that they looked like ranks of windows in the tower. This is an appropriate simile because trilobite lenses do indeed work as a kind of window made of the mineral calcite. Because of the optical properties of this particular mineral, light passes through the lenses normal to their surface, or, to put it another way, it is possible to tell in which direction a given lens could see by imagining a ray of light impinging at right angles to its surface. So it was obvious that this remarkable trilobite could look all around over the sediment surface on which it dwelt, for the lenses were arced in a semicircle in each eye affording a ‘view’ of the surrounding area. It obviously could not look upwards, not least because the eyeshade would inhibit the view in that direction. Then again the vertical arrangement of the lenses meant that the trilobite could see distant objects. The curved nature of most trilobite eyes means that each lens subtends a cone of sensitivity that naturally widens the further away from the eye you are; the sight was good close by and poorer at distance. By contrast, the big-eyed trilobite with its straight-sided eye would have been able to detect small movements in prey even at some distance. But there is a problem here, for distant light is also weaker, and interference from stray rays becomes more of a problem. This is where the eyeshade comes in. For it rather neatly cuts out the light from above which affords the greatest distraction for shallow marine organisms (at moderate water depth light is refracted to come vertically from above). It is rather like a hunter on the African plains contemplating a distant impala by shading his eyes. The trilobite anticipated the baseball cap by four hundred million years.
The remarkable eyes of the Devonian trilobite Erbenochile, seen from the side.
Devonian trilobite Erbenochile. Author’s own collection.
This was an exciting enough discovery to publish a short account of it in the journal Science. The first thought I had was that this must be a new kind of trilobite. My mind began to ferment all sorts of nice descriptive names – Gogglyops or Spectaculaspis perhaps. I had already checked through the trilobite collections to see if there was any specimen that resembled ours – and there wasn’t. But before I got too embroiled in new names I discovered an extremely obscure publication about some rocks in Algeria. Not many libraries have copies of the Notes et Mémoires, but the Natural History Museum is one of them. It was clear from a rather poor illustration published in this journal in 1969 that a similar trilobite to ours had been collected across the border in Algeria not very far as the desert crow flies from Zguilma. Clearly, we needed to know more. Fortunately, we discovered that Pierre Morzadec had refigured this material in a rather less obscure journal, and he had dug it out, or as we say prepared it, rather well from the rock, so that one could see more of its features. He had also given it a new generic name, Erbenochile. However, all the material from Algeria lacked the head, surely the most distinctive part of the trilobite. But close examination revealed that the tail of the trilobite was almost as distinctive as the head, having a very particular pattern of spines around its margin, which was different from that of any other Devonian trilobite. The Algerian specimens were identical to the Moroccan one as far as the features of the tail were concerned. There really was no escaping the fact that our spectacular trilobite species had been named already, albeit from a specimen lacking the remarkable eyes. Applying the rule of priority means that Erbenochile erbeni is the name we must use for our trilobite. If we had not had access to a wonderful library, we could well have got the name wrong, and caused much confusion for future generations.
Another astonishingly spiny fossil trilobite from the Devonian of Morocco: the spines on this odontopleurid are genuine, but fakes are often offered for sale.
Spiny trilobite, odontopleurid. Photo © Brian Chatterton.
This example is typical of the kind of problems that exercise the judgement of a taxonomist, a mixture of scholarly research and careful observation. The history of naming animals and plants is full of examples where labels have been incorrectly applied. In the nineteenth century communication between scholars was imperfect, so it was then quite likely that an animal or plant might have been named twice by accident. The priority rule often had to be applied. I regret to say that there were also numerous cases where scientists ‘rushed to press’ to establish their priority over any potential rivals. One of the most infamous examples concerning fossils was the race between Professors Edward Drinker Cope and Othniel Charles Marsh in the latter half of the nineteenth century to describe and name the spectacular North American dinosaurs then coming to light. This was a case of intellectual war, fought out in publications and in academic disputes. The two protagonists really loathed one another, and each was determined to name any newly discovered animal before his rival. Such enmity certainly stirred up a fever of activity in the prosecution of the war of reputations, but sometimes the casualties were names that got caught in the crossfire. In other examples, it is hard to establish who or what has priority, and the bemused scholar will find himself examining the small print on inside covers to find out whether a given book was published in May or September of 1799. I have used faded library stamps as evidence of the receipt of a publication by the Museum – which must therefore have been published earlier in its country of origin. What is evidently needed is a set of laws to sort out nomenclatural disputes – and so we have the International Code for Zoological Nomenclature, and there is a botanical equivalent. I have to admit that the Code makes for pretty dull reading and can, in the wrong hands, become a pedant’s playground. But it generally works to sort out which name is the valid one. However, there are cases when a rigid application of the Code would result in something silly happening to very familiar names. This might occur, for example, if some bookish scholar discovered a work of unprecedented obscurity containing earlier names for well-known animals. It would be highly undesirable in this case rigidly to apply the rule of priority, for names are a means of communication first and foremost, and nobody wants to revive an old name just for the sake of it. But how can a zoologist decide when to flout the rule of priority? The answer is to apply to the International Commission on Zoological Nomenclature (ICZN) with details of the case in question. With sufficiently good reasons a later name might well be conserved – this is decided by a vote of the Commissioners, who are an international group of taxonomists. Mostly this is just a way of formalizing common sense.
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