The Great Fossil Enigma (41 page)

In November 1973, Sam Ellison, a near-contemporary of Scott, wrote a very brief and formal note thanking him for the paper. Its main purpose was, however, to state categorically, “I remain one of those that believe the animal you describe is an animal that devoured conodonts because from the balled up nature of the complex in the middle of the fish-like remains.” Scott responded, “Also, I take this opportunity to send my personal assurance to you, for whatever that may be worth, that the Conodont animal is for real. I am fully aware of the ‘stomach-ball' canard which was started and I am equally fully aware of the reasons for which this misrepresentation took place. I have always been surprised to what extent scientists will sometimes go to broadcast concepts even though not based upon fact. You may remember that some people did not like my discovery of ‘conodont assemblages' back in 1934, but they have been subsequently found by many people and are accepted, I think, by all.” Scott then gave another reason why he believed the conodont elements belonged to these animals: “Also, every summer's search has uncovered a few additional specimens including some half-size and three quarter-size animals…. I call to your attention that the Conodonts in the half-sized animals are one half size of those found in the adult.” The assemblages within the animals were not mixed but distinct, even though two different kinds of assemblage had been found. “Sam, I write in some detail to you because of our long friendship,” Scott added. “Otherwise, I would probably not write at all.” The defense of his interpretation was full and revealed the considerable logic behind his conclusions. Scott had had other conodont workers visit and leave convinced.

Fortunately, Scott was now in receipt of so much appreciative correspondence that any heartache he felt must have subsided. One young Swedish researcher told him the paper made “very ‘thrilling' reading.” Bill Furnish wrote to thank him, remarking, “I am now one of the few who can recall the excitement of your discovery of assemblages, 40 years ago. It has been even more exciting, I know, to work with the complete remains. These are fine publications to document their exact structure and how they occur. You are to be congratulated on having completed this painstaking research.” One writer complained with tongue in cheek, that he would no longer be able to use Scott's 1930s paper as an example of paleontological reasoning in his classes because the animal had now been found.

In January the following year, Scott was still researching these strange fossils and had written to the Department of Fisheries at the University of Quebec to obtain longitudinal sections of larval lampreys, believing they might have something in common with conodonts. Melton was expecting a visit in March from Preston Cloud, who wished to see the animals and he asked if Scott could return them, adding, “Pres can be a good advocate for them if he is as convinced as we are that the conodonts are part of the animal. I don't think that anyone can look at them carefully and not be reasonabl[y] convinced.” Melton had heard from Ellison, too, who had told him he had “seen the tails of these animals in Kansas City and other localities and didn't know what they were.” He refused to believe in the animals, and Melton wondered if he believed in assemblages. Scott did not contradict Melton; he had long known of Ellison's opinions and told Melton, “It is hard for me to call a man a scientist when he refuses to look at the facts.” As Scott told another enquirer at this time, “There are those in America who would have been happier if the animal had never been found…. The canard, which I mentioned earlier, was started for reasons of pique and in my judgment, was very unbecoming anyone who calls himself a scientist. I beg of you to believe in their existence and that things are reported accurately. Of course conclusions derived from the observations are subject to interpretation…. I assure you that in due course of time, the truth will be accepted.” Scott was rather less convinced that Cloud was sufficiently knowledgeable about conodonts to form an opinion that would be influential but nevertheless believed that he should have access to the specimens. Scott sent them off, telling Melton not to return them but to think about sending them to the National Museum – indeed, with the papers now out, the National Museum requested the material. Scott made assurances to the museum that he would send his material but said that despite repeated attempts to convince Melton to do likewise, the best specimens would remain in Montana. Scott was now preparing to retire, but before he did so he began to adapt to the new taxonomy and accepted that
Lochriea
was to be a synonym of Schmidt's
Gnathodus.
Meanwhile, in Japan, there were preparations for the translation of the paper.

In June, Scott retired, intending to continue to work on the animal and believing that history would eventually prove him right. Bear Gulch had, by this time and as a result of work Scott had directed, become internationally important. The outcome for the animal was far less clear, and many – perhaps most – joined with Ellison and others in being disbelievers. Scott imagined this the work of conspirators upset by his actions following the 1969 convention, but Lindström was not among these. He had listened to Scott at the East Lansing meeting, looked at his material, and immediately become a disbeliever. Scott could only see this doubt as politically motivated rather than reasoned. As he told Ellison at the time, “I suppose that once a false idea catches on, it will take years, if not a generation, for that idea to be lost…. In closing, may I say that I too am often a doubter and at times even a heretic. Insofar as the Conodont animal is concerned, I do not fall in the group of doubters and neither will anyone else in due course of time.” Scott considered taking a lecture tour with specimens in hand to all the centers of dissent in order to quash the “meat-ball” hypothesis. As he told another correspondent, “It becomes a mathematical impossibility for these to represent anything except the true animal. For these reasons, I think the search for the animal is over.”

 

TO MOST OF MELTON AND SCOTT'S CONTEMPORARIES, THE
conodont animal from Bear Gulch seemed impossible, even ridiculous – the latest and most spectacular addition to a heap of such impossibilities. To Melton and Scott, and a few others, of course, it looked entirely plausible; the reasoning that had brought it into existence was sound enough. Most conodont workers, however, liked to imagine the animal existed elsewhere. Some even thought it might already exist but remained lost in a paleontological blind spot – known but not recognized. A long list of outsiders had taken this kind of thinking to the extreme and imagined the key to the mystery already existed out there in the zoological world. With this thought in mind, we might ask if it was really so ridiculous for the young Klaus Fahlbusch to propose, in 1963, that conodonts were secreted by algae? Lindström, who had just sent his conodont book to the publisher, simply could not believe it, and Ziegler, who examined Fahlbusch's material, told him not to. In his naïvety, Fahlbusch had hit a hornets' nest, and almost immediately the swarm (Beckmann, Collinson, Helms, Huckriede, Klapper, Lindström, Rhodes, Walliser, and Ziegler) was upon him, stinging him with accusations of poor science. Later, Lindström would feel nothing but regret for this incident, but when he did, he had perhaps forgotten that “conodontology” was not, in 1963, the respected science it was to become. It was still scrambling for recognition. In time, however, Fahlbusch would find some relief, for it was in this paper that he also told his seniors that their methods of acid preparation were damaging their fossils. On this point, too, they were outraged, but here Fahlbusch was to be proven right. And, as it turned out, he was not the last to look at this group of fossils and see plants. In 1969, Felton Nease published a paper suggesting that bar-like conodonts formed the midrib of aquatic plants found in the Chattanooga Shale, plants he called
Conodontophyta chattanoogae.
It was a suggestion treated with laudable seriousness by Huddle in the
Pander Society Letter
, although the idea must have tickled the conodont research community, which was then sufficiently mature to be unruffled by such outlandish ideas.
¹
Many years later, conodonts would again be mistakenly identified for plant remains, but on this occasion, as we shall see, it led rather unexpectedly to discoveries of huge significance in the hunt for the animal itself.

The 1960s are remarkable for the degree to which the nature of the animal was
not
discussed. This was a period of intense conodont research, but Wilbert Hass's and Walter Gross's work had made the subject of the animal a taboo. The animal had become unimaginable and the fossils themselves simply provided insufficient data to resolve the matter. Of the new generation, only Lindström broke this silence. The first to write a monograph on these fossils, in 1964 he had no choice but to ask what form of life had possessed them. It called for some deductive reasoning, but this is an art in which Lindström was to excel.

He started with what had become a fundamental question: Are the conodont elements internal or external structures? Hass had argued that the manner of their growth meant they must have been surrounded by tissue. If they, like teeth, then emerged, growth would stop and wear would begin. But Hass found no wear, only breaks that had been repaired; as the broken part had not been lost, it seemed logical to believe it had been retained in a fleshy covering. Frank Rhodes had not been entirely convinced by these arguments and thought the hardness of the conodonts prevented significant wear. He also believed broken parts had been lost. He, too, thought the assemblages must have formed “ingestive aids” but felt the conodont elements were probably exposed and attached only at their bases. It was Gross's later study of the base that finally put paid to this idea.

Lindström believed the fragility of the conodont fossils made them unsuitable for active food gathering and thought it more plausible that they were covered in flesh. What stood in the way of this interpretation was evidence of lost parts and wear, but Lindström thought reported losses could be explained by parts being “resorbed” or expelled. Wear was more of a sticking point, but there was no agreement on whether it could be observed. Lindström searched for an alternative explanation, suggesting that what looked like wear might instead represent “retarded growth.”
²

The animal Lindström was to build relied as much on these explanations or interpretations as on the facts as they were then understood. But, then, many of these facts were also interpretations. What Lindström was searching for was firm ground – a group of judgments that might legitimately be used as building blocks for the imagined animal. He began by establishing that the conodont elements may have been embedded in tissue throughout the life of the animal. That was the new orthodoxy. If so, then how did they function? That, he reasoned, might depend on the animal's mobility, and this in turn might be discerned from its symmetry. If bilaterally symmetrical, it was reasonable to believe the animal had been a swimmer. But some workers had reported asymmetrical assemblages, which encouraged him to think that some conodont animals may have been colonial, floating passively in the sea. This was, however, just a possibility.

The animal that began to form in his mind possessed numerous protective spiny elements: “The broken and regenerated denticles show that protection was wanted but also that the animals could escape alive after being attacked.” But, he asked, were the preserved conodont fossils really fit for a protective role? He could imagine more formidable architectures if this were their primary function. He decided that he needed to think beyond these active roles and so returned to Hass's suggestion that they were supporting structures. What could one imagine if one looked at the range of elements said to be possessed by a single animal? Depending on the shape of the underlying element, one could visualize finger-like projections of flesh perhaps with tiny nipple-like coverings or fringes. If the morphology of the elements closely reflected the form of these fleshy extensions, some could be brush-like. Lindström also imagined other tentacle-like projections unsupported by conodont elements, or perhaps supported at one point in their evolution, then lost, then reappearing later on, as the fossil record seemed to suggest. Why, then, he asked, are there no instances of elements fusing together as the animal evolved? Lindström asked Rexroad if his fused conodonts indicated an evolutionary development but Rexroad thought they did not. Perhaps this meant that the organ of which they were a part had to remain flexible? Perhaps the animal could thrust its denticles outwards in defense? Perhaps the whole organ could expand and contract to draw in and expel water? The possibilities were considerable but were any really plausible?

The exact form of an organ composed of all the parts of an assemblage would, he knew, depend on its functions: food-gathering, respiration, defense, etc. The only test was to attempt the construction of what appeared to be a plankton feeding organ using the best information then available concerning the relative position of the parts. Cilia were then introduced to direct food along grooves that converged on the mouth. What he produced and illustrated in elegant detail was a hypothetical lophophore, a usually horseshoe-shaped organ of ciliated tentacles found around the mouth of certain aquatic animals that strained particles out of the water (
figure 12.2a
). By imagining a lophophore, he shifted his hypothetical structure into the realm of known biology, giving it greater plausibility. Lindström knew that brachiopods had lophophores with mineralized skeletons to support them and that lophophore-possessing animals were particularly common in those seas that held the conodont animal.

Even if the animal that appeared in Lindström's book had no effect on his fellow conodont specialists, others looked at it and thought they saw the state-of-the-art conodont animal rather than one man's thought experiment. There would not be another conodont monograph for a quarter of a century, and the next
Treatise
was still seventeen years away. Lindström's book became a key point of reference, especially for those who were not conodont workers. British paleontologist Bev Halstead, for example, took Lindström's animal and, reversing the flow, believed he saw a convincing filter-feeding animal. It was this that impressed Scott.

Lindström's book did nothing to disrupt that long shadow cast by the microscopy of Hass and Gross. Indeed, Lindström had constructed his own interpretive spectacles from their studies. They had demonstrated that fishes, worms, and teeth were illegitimate thoughts, so Lindström had imagined something else. Indeed, Hass and Gross's publications had made an area of investigation unattractive, as the effort required to take these studies further would be colossal, require extraordinarily well-preserved fossils, and carry a high risk of turning up nothing new. Consequently, their views stood without further testing. This set of circumstances gave their ideas a natural resilience. Unable to modify or overturn them, those who wished to progress the science of the animal had to accommodate them.

In time, however, technologies improve and open up new ways of seeing. Each generation that had used the microscope to study the conodont knew there was a resolution of observation beyond which they could not go. As if in a fog, and just beyond view, there were always tantalizing glimpses of structures awaiting technological advance. Here too one could imagine one saw El Dorado faintly in the distance. In the first
Treatise
, written in the 1950s, the conodont fossils were magnified up to 420 times and illustrated as two-dimensional slices or thin sections. By the time of the second
Treatise
, written in the 1970s, three-dimensional images were possible with magnifications of up to 8,000x, though this extraordinary degree of enlargement was rarely needed. This leap in the ability to see had profound effects on the nature and form of the object; a new object – a giant object – emerged through the fog. Now conodonts were, effectively, twenty times bigger, and it was possible to see into their deepest recesses. The science had advanced into the world of the tiny and so acquired a language of “micromorphology” and “ultrastructure.”

This breakthrough, which occurred in the late 1960s, came with the arrival of affordable scanning electron microscopes
(SEMS).
Seeing a new territory open up, which was certain to deliver new knowledge, the conodont workers rushed in. At Marburg University, Lindström, Ziegler, and a track record in conodont research proved sufficient to get one of the first
SEMS
installed; the university had been willing to give Lindström anything he desired in order to secure his services. The Marburg instrument found its main use in the study of conodonts, with Ziegler being among those who, in 1968, first published an
SEM
study of conodont structure and chemistry.
³
He and Lindström became fascinated by the new patterns they observed on the surfaces of the fossils: polygons, furrows, tiny denticles, pits, and so on. One structure looked like a plaited loaf. Was this the remnant of an organ of some kind? They never quite knew what the
SEM
might throw up.