Ammonites, were they really capable of swimming or floating ?
Certainly not, without any exception ammonites were unable to swim or to float. Although these animals were able to lower their shell weight by the gas-filled chambers nevertheless this reduction was too little to ensure neutral buoyancy. Meaning and purpose of the phragmocone are unknown up to now, and whether the shell had a protective or another additional function. Maybe, the curious shapes of heteromorph ammonites can be used as an indication that the shell was relatively unimportant. Contrary to the living Nautilus, which by the way is a very far away relative, ammonites were too heavy to live in the water column. Under favourable circumstances occasionally, but not in general, empty shells could ascend to the surface and drift ashore or into lagoons.
By means of calculations I have offered proof of the missing neutral buoyancy, using a computer program and the hydrostatic law found by Archimedes already 2000 years ago. Former ideas by palaeontologists about the lifestyle of ammonites were based on mere speculation without any scientific confirmation. All ammonites were bottom-dwellers and could move on the bottom only by crawling.
Although it may take a rather long time, finally the new idea will find its way irresistibly. The above foto shows a herd of crawling ammonites (gender Ceratites) in the diorama of the Naturkundemuseum Willibaldsburg Schleusingen in Thuringia, taken by Siegfried Rein.
My investigations have found some corroboration meanwhile :here
My first contact with ammonites happened in 1974 when I visited an old quarry together with my younger brother. After less than one hour I held my first ammonite in hands, a Macrocephalites. Although interested in geophysics and geology already for many years I was surprised that it could be so easy to find a fossil, and soon collecting ammonites became a nice hobby, by which I gained many specimens for further studies. But in the long run collecting was not really satisfying. My intention was to get to know more about these extinct animals. From the first find already I was concerned with the question why the shells of ammonites differ markedly from the smooth shell of the extant Nautilus. I tried to gather more informations about these fossils and the mode of life of the former animal. Since in the beginning I had uncritically adopted the current view of swimming ammonites, the differences were unexplicable to me. Several years I meditated over this problem until finally the idea occurred to me that in ammonites an additional force apart from weight and buoyancy was permanently active. This force could only be a pull, and a pull again could only be present between the animal and the ground. Therefore, ammonites could only have been bottom-dwellers.
I talked to a Tübingen palaeontologist about this idea. As usual in such cases he was sceptical. Nevertheless, he gave me the good advice to support such an idea by calculations which might convince or at least make silent the lurking critics. I was astounded that so far nobody had calculated weight and buoyancy of ammonites. Since I had already written computer programs for my professional work, an ammonite program was a relatively easy task to me, and I could make it run within a short time. In addition, as an experienced engineer in flight physics I am familiar with mechanics, hydrostatics, hydrodynamics, and of course with aerodynamics. It is a fundamental problem that such tools generally are not available to palaeontologists, respectively cannot correctly be applied. Unfortunately, they even seem not to have learned to interpret results by use of abstractions. For this reason, palaeontologists are restricted to propagate opinions, guesswork, and to their endless controversal debates without ever arriving at unequivocal results. Such procedures cannot lead to progress. It’s a pity!
I must admit that I received much pleasure by the fact that I could base my ammonite calculations to some extent on measurements of shell thickness carried out just by G.E.G. Westermann, the undefatigable herald of swimming ammonites and inexorable opponent to diverging ideas. Fortunately, he could not attack his own work. Though without any doubt he was an excellent expert of Jurassic stratigraphy and ammonitic forms, unfortunately, this knowledge is not suitable to make him automatically a guru concerning the lifestyle of ammonites. Nevertheless, using a different approach, I found his measurements reliable.
Already in 1941, A.Trueman had carried out calculations as to some intrinsic features of ammonite shells. However, the wonderful formula he used did not allow statements about weight and buoyancy. As all other palaeontologists before and after him he assumed neutral buoyancy. So far, the problem of the unknown lifestyle of ammonites had not at all been tackled with all scientific methods available, on the contrary palaeontologists have relied on a pretended close relationship with modern representatives of cephalopods only. Concerning fossil forms they have guessed, speculated, and attempted to achieve a consensus among the ‘top-ranking experts’ in this field, by vote so to say. Such an attempt is unacceptable. Unbiased people prefer to rely on the unrestricted validity of well established natural laws, on applied physics. In this case a recognition can only be right or wrong. This certainty makes investigations as I have carried out so satisfying, makes even happy.
A prognosis as to the ontogeny of certain gastropod shells derived from my statements about the ontogenetic development of heteromorph ammonites has been confirmed by experiments carried out by Checa & Jiménez-Jiménez (1997) who attached small weights to one flank of planorbid gastropods causing deformations, as I had predicted. Thus, the shell growth of heteromorph ammonites can be traced back to similar conditions, i.e. to variably acting external forces. These results can be regarded as an additional corroboration of my considerations.