Preface

   

ERNST, Hans Ulrich & Christian KLUG:

Perlboote und Ammonshörner weltweit

Nautilids and Ammonites worldwide

Preface

Among the invertebrates, the cephalopod molluscs doubtlessly produced the most intelligent organisms which populate today’s oceans. Both the cognitive performance of trainable octopuses and the perfect mimicry of numerous squids are fascinating; as “chameleons of the oceans” they can turn invisible by adapting their pigmentation to their background within seconds or they imitate coeval predators in order to protect themselves from attackers. Cephalopods also hold a number of world records, which would be worth being mentioned in the book “Guinness world records”; for instance, the legendary giant squids are the largest molluscs on earth and additionally, with a diameter of up to 20 cm, their eyes (which closely resemble vertebrate eyes) are the largest among all animals. As documented by BERNHARD KEGEL’s novel “the red”, the monstrous giant squids from the abyss fire mankind’s imagination since the middle ages up to now. The usually hardly over 20 cm measuring nautiluses which live between the tropical island paradises of the Pacific also hold a world record: they lay eggs with a diameter of more than 2 cm, which thus are, in relation to their body volume, by far the largest eggs among all invertebrates. Modern squids could be record breaking concerning the yield of high grade biomass by mass reproduction in a rapid sequence. Regarding the intense overfishing of the world’s oceans, cephalopods might ensure the survival of significant parts of mankind because their potential as a food source is currently exploited only fractionally. Due to this fact, the research on cephalopod evolution and ecological needs receives increasing significance.

With their chambered shells, external in Nautilus and internal in Sepia-like animals, cephalopods developed the technology of submarines long before mankind; an elaborate system of water-exchange in the basically gas-filled chambers enables these animals to achieve an energy-saving balance of their buoyancy in the water column. This balance can be adjusted to the corresponding diving depth.

Especially the nautilids connect us, as far as some aspects of mode of life and the organism’s form are concerned, with the ammonites because, as “living fossils”, their common ancestors originated already as far back as approximately 500 million years. This is of great interest since ammonites represent the most famous fossil group of the Palaeozoic and the Mesozoic. The aesthetics which emanates from the often opulently adorned spiral shells, especially when preserved with their colourful mother of pearl shell-layer, has stimulated mankind’s imagination around the globe. Both in the old world and in northern America, indigenous people have assigned magic, cultic, ruminant and even fertility-increasing properties to these fossils. The oldest evidence for the attention ammonite fossils received from humans was discovered in the Vogelherd-Höhle near Ulm; these discoveries of ammonite fossils show traces of human processing from the late Palaeolithic. It thus comes to no surprise that such objects have found their way into philately.

Ammonites are captivating because of their inexhaustible variety of shapes, but also because they constructed coiled conchs with a diameter of far over two meters as testified by ammonite specimens from the Cretaceous of the Münsterland in Germany [translator’s note: this has nothing to do with monsters or “the munsters”]. In addition to the tremendous diversity in variably shaped species, the morphological spectrum of ammonites is even increased by the occasionally extreme sexual dimorphism. Shells of male animals often show extreme differences to their female counterparts not only in size but also in the aperture shape and in ornamentation. Ammonoid phylogeny is in many cases documented in almost each single evolutionary step in the stacked sequence of sedimentary rocks. These evolutionary lineages made ammonoids especially attractive study objects already in the 18th century. In the course of their approximately 350 Million year-predominance in the planet’s oceans, ammonoids experienced several crises during global mass extinctions. Except for the last major mass extinction at the end of the Mesozoic 65 Million years ago, they always managed to survive each of the major crises with one tiny group. Their intermittent evolution still represents a stimulus for the recognition of patterns and mechanisms of biodiversity dynamics, partially because of their rapid post-extinction radiations which repeatedly yielded a plethora of new species. Iterative evolutionary pulses of the ammonoids were also affected by the change from the characteristically predatory mode of life towards a microphagous plankton-feeding mode of life.

The spiral shell is characteristic for modern nautilids as well as most ammonites. Its seemingly perfectly geometric shape epitomises the symbol of the universal principle for meditation purposes in many esoteric philosophies. Both nautilids and ammonites both independently and repeatedly evolved such coiled shells from the straight ones of their ancestors. Its functional driving force is that the soft body attains a horizontal orientation which is advantageous for horizontal swimming by this spiralisation. Their ancestors with straight shells had the gas-filled chambered part at their rear end which forced their soft body in a downward position.

With this book, the two authors complement one another in an optimal way and present an appealing compilation of cephalopod-illustrations on stamps and postmarks. It gives in-depth information on the philatelic background as well as on the anatomic-scientific specifics of the illustrated objects. I am convinced that this book will convey the enthusiasm for these fascinating organisms to a new group of people by the indirect occupation with ammonoids via philatelic illustrations, what usually occurs to scientists and fossil-collectors by the direct contact with the actual objects.

Berlin, January 2009
Prof. Dr. HELMUT KEUPP
Freie Universität Berlin

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