The Great Fossil Enigma

by Simon J. Knell

  A few years later, Gross produced the first detailed description of the “basal structure” of the conodont, a component that had largely been ignored. He revealed that an extraordinary cone of material, composed of lamellae, sometimes extended well beneath the conodont element as commonly understood. It appeared to grow by additions inside the large cavity of the base such that the cavity might become completely filled. Unknown to Gross, the young Maurits Lindström, in Sweden, had published something similar two years earlier but had done so in a journal so obscure that no one had seen it.13

  Gross took his work on the base a little further in a paper in 1960. By that time the argument was being conducted on points of extreme detail.14 The base and the crown were then to be understood as a single continuous unit, with the crown – the conodont fossil of common understanding – being more significantly mineralized.

  In a few short papers, Walter Gross completely altered the zoology of the conodont. Delivered with Gross's considerable scientific authority and building upon the doubts of Hass, it tore the conodont fossil out of the mouths of fish and worms. Now it was even more incomprehensible. So original, meticulous, and convincing was Gross's work that it cast a long shadow. In the 1960s, few would consider the nature of the animal and almost no one thought of these fossils as teeth. Those who might wish to dissent knew they would need better material and improved technologies. These did not arrive for a decade.

  Few paleontologists shaped the fossil so fundamentally, but Gross was not to become a conodont worker. This was just an excursion by a specialist in fossil fishes who effectively swept the conodont out of his field of concerns. Gross remained in East Germany for a while but became an increasingly outspoken political dissident. Schindewolf orchestrated his “escape” to the West and to Tübingen in the early 1960s just as the Berlin Wall went up.

  Müller was not particularly impressed by Schindewolf, who had risen to become the leader of German paleontology after the war. He favored other candidates. He had remained in the east of the city after the war, undertaking his doctorate research on the cephalopods of the Devonian of Thuringia in East Germany. But when he stood for examination, the university's Soviet-controlled authorities told him that he would also need to write on communism. The very idea was an anathema to him. Fortunately, just as the Soviets were inflicting their politics and ideologies on the old university, plans were being developed to erect the Free University in the west of the city. Now, with the aid of professors in both universities, Müller escaped, in what was still merely a bureaucratic exercise, to the west of the city.

  At his new department at the Free University, Müller was given a small position, but he was already suffering from acute tuberculosis of the kidney. It was simply the next in a series of diseases that would affect his life. Müller was so stressed by the urgent need to get his PhD finished that his doctor found him unresponsive to treatment. “How long do you need to finish your thesis?” his doctor asked. Müller said, “Three days.” When those three days were up, Müller returned to the hospital and spent the next year there, before leaving the “flatlands” to recuperate in the Alps, in the manner of Hans Castorp in Thomas Mann's famous prewar novel The Magic Mountain. At the insistence of his wife, Eva, who was always his voice of reason, Müller eventually left his retreat to return to the life of a geologist. He did so reluctantly.

  Conodonts had still not entered his thinking, and back in West Berlin, he was a geologist trapped in a half-city surrounded by the communist “East.” His research sites in Thuringia might just as well have been on another planet; he had no chance of collecting there now. Out of desperation, he took the remaining samples of limestone left over from his PhD work and dissolved them in acetic acid. In them he found hundreds of conodonts, and from these he published his first conodont paper in 1956. In the middle of writing it, he traveled to Iowa, the new U.S. capital of conodont studies. It was not his intention to stay there, for he had wanted to tour the country, but his active tuberculosis, the offer of free medical support, and the wise counsel of his wife, meant he remained in the one spot. There he spent two years in the company of Miller and Furnish and wrote his own summary of conodont studies.15 It was a paper, like other contemporary accounts, that showed the conodont to be a vehicle for creative thinking. Of all the fossils, it seemed open to new views and new solutions. There were no senior workers to control or constrain thinking, or maintain orthodoxies.

  In his review, Müller recognized that the rapid evolution of the platform elements – so useful to Branson and Mehl – provided the key for identifying and naming whole animals because it was these elements which distinguished them. One did not need whole assemblages to name whole animals, he thought. The approach had worked with fossil mammal teeth, so why not conodonts? Müller admitted to the subjective decisions paleontologists needed to make to document evolution but nevertheless believed it was possible and preferable to construct a natural rather than a utilitarian system, even if using isolated elements. However, even among the new generation there were those who disagreed. The young Lindström remained attached to the old ideals of the stratigrapher: “The object of the classification of isolated conodonts could not be to expound phylogenetic relationships between the different kinds of conodonts. Classification of isolated conodonts rather has to restrict its aims so as to provide the worker concerned with conodonts, especially in the field of stratigraphic geology, with clearcut morphological categories.”16

  In 1956, the physically weak Müller felt empowered as the conodont world was remade with acids and new thinking. Having written his thesis on Devonian cephalopods, he now felt he might be the person to tame the European Devonian using the conodont's newfound ubiquity. He was, however, unaware that many other German minds were thinking similar thoughts, for he was isolated from his compatriots by illness, politics, and travel, as well as his preference for lone working.

  Müller had no knowledge of what had been happening at the ancient University of Marburg. Here, in 1949, Beckmann had demonstrated that Branson and Mehl's contentious but wonderfully useful Grassy Creek conodonts could be found in Germany. As his rocks were rather better studied, Beckmann could now confirm that the Grassy Creek was not only Upper Devonian in age but that it occurred in the lower part of that division. Beckmann's paper on acids followed, in 1952, and then, in the spring of 1953 at a meeting of the Deutscher Geologischer Gesellschaft (German Geological Society) in Dillenburg, he revealed the true potential of the conodont for the high-resolution stratigraphic study in the German Devonian and Lower Carboniferous. The impact on his audience was immediate. A magical solution that overcame supposedly “unfossiliferous” strata and the patchy distribution of other fossils seemed to manifest itself before their eyes. The conodont was ubiquitous, could be processed with little effort, and opened up the possibility of studying rocks on a centimeter-by-centimeter scale. Exploiting fine and increasingly well studied German rock sequences, this audience imagined that a dedicated conodont worker might “influence biostratigraphic interpretations throughout the world.”17 Beckmann had fired a starting gun and a new generation rushed forward.

  6.1. Four harbingers of spring, captured in later life. Clockwise from top left: Otto Walliser, Maurits Lindström, Willi Ziegler, and Klaus Müller Photos respectively: Dick Aldridge; Helje Pärnaste; Senckenberg Gesellschaft für Naturforschung; John Huddle, courtesy of John Repetski.

  A school of conodont studies was established at Marburg in Beckmann's wake in which Willi Ziegler, Günther Bischoff, Ursula Tatge, Otto Walliser, Hans Bender, Dieter Stoppel, Reinhold Huckriede, Peter Bender, Hans Wittekindt, and others came to work on these fossils. It became a site of intensive research activity. Beckmann's influence spread to all corners of the soon-to-be-divided country. Dietrich Sannemann at Würzburg, for example, was the first to confirm Beckmann's results with his own pioneering study.18 At Humboldt University, Joachim Helms, an assistant to Gross, began working on the conodonts of Müller's Thuringia arou
nd 1958.

  In Marburg, Bischoff and Ziegler began as PhD students under the supervision of Professor Carl Walter Kockel, who, although an excellent tutor, actually knew little of conodonts. Bischoff took inspiration from Hermann Schmidt, then a Göttingen professor, and collected limestone samples from the Devonian-Carboniferous boundary under Schmidt's guidance during the Arnsberg conference of the German Geological Society in 1954. Bischoff was astonished by the wealth and variety of conodont material this produced, and at the clear faunal change that appeared to separate the Devonian from the Carboniferous.19 Using this material and the security of the cephalopod fossils that already divided up these rocks, he could, unlike American workers only a few years before, be certain of this change.

  While Bischoff worked at the top of the Devonian, Ziegler began an assault on the poorer faunas of the Lower and Middle Devonian. Before long the two men were working closely together and attempting to create their own parallel chronology to mirror that based on cephalopods. Throughout the mid- to late 1950s, the combined effort of these young Marburg scientists continued to reap results and the foundations were laid for major developments in the following decade.

  In 1958, a position came up for a conodont specialist at the Geological Survey at Krefeld. Müller was approached, but hearing that the organization had no director and was moribund, he declined. Ziegler was less choosy, and already rather more attached to conodonts than Müller, and he accepted the post. Driven to succeed whatever the organization's circumstances, Ziegler's energy and single-mindedness, applied in a full-time position, left Müller standing. Ziegler probably understood that it would permit him to outcompete those who shared his ambitions. Müller now looked on helplessly as the door shut. The German, and with it possibly the world's, Devonian now belonged to Ziegler.

  Müller's survival instincts kicked in. Better to enter an uncompetitive field than to fight; Müller was not much of a fighter. Perhaps he would be able to do in the Silurian what he had planned for the Devonian? Müller turned to the excellent Silurian sections in the Carnic Alps on the border between Austria and Italy. This field work also had the advantage of altitude, so beneficial to his ongoing health problems. But he had not been collecting long before he discovered he was not alone. Otto Walliser shared Müller's new ambitions.

  Like Müller, although somewhat younger, Walliser was a survivor of the war. He had imagined a career in the realm of living plants – in his case forestry science – but the university in his home town of Tübingen offered no such course. However, geology seemed to fit with his nature-loving instincts, and he soon developed the ambition of becoming a museum curator. Tübingen also had the distinction of being home to Schindewolf, from whom Walliser would learn some of his geology. On completing his degree, Walliser moved to Marburg. He was already becoming a specialist in Lower Jurassic ammonites, but he was also aware that he was entering the new German center for conodont studies. And as he was to be senior to the younger Ziegler, Bischoff, and Tatge, he thought it judicious to take an interest in these fossils. With the Devonian and Triassic niches already filled by those he was joining, he fixed his attention on the Silurian. From his first trip to the Frankenwald, he returned with a single sample that proved by far the richest in conodonts in his whole career. This demonstrated the potential, and so he began working on the Silurian of the Carnic Alps.

  Walliser had worked on these rocks for a year before Müller appeared in search of upland solitude. For both men this was a problem. Müller had funding from the national geological society but now found himself in the embarrassing position of possessing a grant for a project that lacked the scientific novelty he had claimed. Walliser was already considerably more advanced in his studies. Müller asserted his right to proceed on the basis of the support he had been given. Walliser claimed the advantage of being the first and of being self-funded; he was not going to give way. Someone suggested the compromise of collaboration, but Müller, who kept his tuberculosis hidden, knew his health would not take it and declined. He knew Walliser was strong and an exceptional field man. In the end a compromise was negotiated: Müller agreed to deal with the simple cones and Walliser with the rest. Walliser gave Müller all his simple cones, but Müller failed to keep his part of the bargain. Walliser then had no opportunity to do the work himself. The two men remained on bad terms throughout their careers. Only in retirement, decades later, did Müller write to Walliser to express his regrets.20

  The outcome for science of this face-off was, however, hugely positive for both men. Müller did not, in the end, stand his ground and was forced to drop down even deeper in the stratigraphic column, into the Cambrian, which for most conodont workers was completely off the radar. Here he had space to make the most remarkable discoveries and achieve real distinction. In 1975, Müller, now perceived as a Cambrian specialist, found his life change again when he accidentally discovered the finely preserved “Orsten” fossils. Then fifty years old, he effectively gave up conodonts to pursue these new and extraordinary fossils, and a new community of researchers grew up around him. Fossils preserved in three dimensions and in exquisite detail, he was able to challenge the interpretation of one of paleontology's most iconic objects, the tiny and strikingly odd trilobite, Agnostus. Müller felt he proved, on the basis of remarkably preserved soft parts, that this famous fossil was not a trilobite at all.21

  As for Walliser, he soon had the Silurian to himself and in a few years had singlehandedly tamed it. He in time became drawn to far bigger questions concerning the history of the planet. We shall return to both these men.

  Before 1950, Sweden had played little role in the development of conodont studies, and in common with much of the rest of Europe, it barely knew these fossils. Among these earlier Swedish workers was Assar Hadding, who had described a dozen conodonts in his 1913 doctoral thesis on graptolites. These fossils had been found in Ordovician rocks not far from Lund, where Hadding was, from 1947, rector of the university and a prominent figure in Swedish geology. A stratigraphically isolated fauna, Hadding's finds had no real scientific impact, but Swedish geologists became aware that there was a group of fossils they had overlooked.

  The Swedish workers who entered the science in the 1950s invariably possessed botanical roots. This interest in plants and their taxonomy owed everything to Sweden's great hero, Carl Linnaeus. So it was that Sweden's conodont pioneer of the new generation, Maurits Lindström, was required as a schoolboy to collect and curate a herbarium, along with every other twelve year old. He was expected to know and to be able to identify some twelve hundred plant species. Stig Bergström, who became established as a leading conodont worker in the early 1960s, began as a particularly outstanding botanist. “But when he came across the conodonts he found in them such potential and such beauty,” Lindström later reflected, that Bergström decided “that this should be it!”22 Lennart Jeppsson, a still later worker, also came to this science through botany. We shall come to these younger men in due course. For Lindström, plants were not a first love, but they were a means to gain rapid entry into university, and this he did.

  As a schoolboy, Lindström had made a small study of the Middle Ordovician, not far from where Hadding had collected his material. He wrote this up and presented it to his biology teacher, who was completely amazed by it. Encouraged, he continued to work on it after 1950, publishing it in 1953 when nineteen or twenty years old. Lindström was a schoolboy paleontologist.

  In 1949, and still in his mid-teens, he had the opportunity to study geology under the distinguished Swedish stratigrapher J. E. Hede, where he now found himself by far the youngest in a class of just three. His compatriots were, to his eyes, like uncles; he still considered himself merely a schoolboy. Hede was by this stage rather elderly and his method of teaching rather archaic; he would read out the essential content of a paper published perhaps twenty years before, showing illustrations and drawing beds and listing fossils, and expect the students to make copious notes. Lindström remembers
clearly the fleeting moment when the conodont appeared mainly for its political message, as this was a university where Hadding ruled: Hede said, “Conodonts are probably worm jaws but one can generalise and say that they are essentially anything small and spiny described by an incompetent palaeontologist!” Lindström soaked up this mass of geological information undeterred by the formality of its delivery. Now he at least knew of the conodonts, but he was yet to really know them.

  Around 1950, Lindström came across papers by Russian and Indian workers discussing the sensational discovery of very small plant fragments, including wood, in rocks of Cambrian age.23 These were puzzling discoveries of things that had no right to occur in rocks so old. Lindström was encouraged to begin his own investigations. In his student room, he set up a small laboratory and began dissolving bituminous limestones with hydrochloric acid. The stench of acid and bitumen was everywhere. Among the fossils he found were some odd spiny fragments, which were clearly not plant remains. He took these to Sweden's leading micropaleontologist, Fritz Brotzen, in Stockholm. A fugitive Prussian Jew and German autocrat, Brotzen told Lindström, in his strange Swedish, that they were probably trilobite fragments and not very interesting. He advised Lindström to take up the study of fossil fishes instead – fossil fishes then being a Stockholm strength – and then sent him to see Erik Stensiö, the country's leading fish paleontologist. Stensiö presented Lindström to his assistant, Erik Jarvik, who later became Stensiö’s successor and who was then working on the structure of the teeth of primitive fishes from Gotland. Jarvik had extracted these teeth from limestone using acetic acid, after which he thin-sectioned them and studied their microscopic structure. Lindström was impressed. Jarvik showed interest in Lindström's fossils but advised him, “Use 10% acetic acid and you will experience wonders.”