Rarest Fossil Ammonites: Nature At Its Most Bizarre,
Heteromorph carries a recommendation from the Geological Society of London. Heteromorph includes a two page limited glossary and a two page listing of photo and art credits. I purchased this through Amazon but the only way to get it was through their associated sellers. Prices vary depending on the seller you choose but I paid $45.00. At the time I wrote this review, Amazon had a single copy of the Collector’s Limited Edition listed for $200.00. This version is slip cased, signed by the author, and limited to 100 copies.
Grulke is listed as an author and business man living in Osborne, Dorset in the U.K. Doing a Google search produced much more about Grulke. Now retired, he spent 25 years with IBM and is known for his books on innovation and the future. He is currently listed as Chairman Emeritus of Futureworld International Ltd. Besides his business related experience, he has expertise in paleontology and marine biology. Grulke has published on ammonites from Madagascar in African Natural History, Vol 3, 2007. Based upon reading Heteromorph, it appears he is heavily involved in the excavation of heteromorph ammonites in Morocco. I would also say that his efforts are saving these specimens from the grips of questionable Moroccan preparators.
The cover of Heteromorph is impressive featuring what appears to be an artist’s creation of various ammonites arranged in a giant sculpture. But this is not a sculpture at all but a death association of ammonites skillfully prepared from solid rock to reveal the beauty inside. More amazing and beautiful ammonites await between the covers including a much larger death assemblage collection. The book is profusely illustrated with color and black & white photographs and drawings.
At this point you may be wondering just what is a heteromorph ammonite? The root words give a hint, hetero = different while morph = shape, so different shapes. This group includes all ammonites that are not simple planispirally coiled forms. These are the ones with coiling like snails and hooked ones with shapes like paperclips. Many combine these odd forms and one type from Japan resembles a knot. Most of these bizarre forms lead to questions about the life orientation of the animal especially since it had to change its orientation as the shell form changed through growth.
Heteromorph begins with an introduction placing these forms within geologic time and alongside cephalopod relatives including nautiloids and the orthoconic forms that are locally abundant here. Differences between nautiloids and ammonites are described.
In discussing the design of the shells and the complex sutures, Grulke talks at length about the work of Benoit Mandelbrot who developed the field of fractal geometry. Mandelbrot felt that randomness was a key in nature and that fractal geometry was the key to many shapes in nature. Others applied his ideas and found that the intricate shapes of the ammonitic sutures may in fact be derived from fractals. Yet other scientists have applied differential geometry to computer modeling and were able to have computers generate shapes that match actual heteromorph ammonite shell forms.
In his chapter on evolution and development, Grulke shows orthocerida cephalopods as ancestral to the nautilida and indirectly to the ammonoidea. The reference for this was a 2011 work by Kröger, Vinther, and Fuchs on cephalopod origin. One interesting point to note is that the heteromorph shapes in ammonites evolved and fell to extinction on three separate occasions - during the Triassic, the Jurassic and the Cretaceous. Considering the question as to why the strange complicated shell forms evolved, Grulke offers that their form may not have been driven by natural selection pressures but merely by random mutations. In addition, a standing myth about the complex sutures of ammonites has been debunked. It had long been stated that the complexity of the sutures allowed ammonites to withstand higher water pressures allowing them to seek deeper water environments than nautiloids. Interestingly enough, the chamber walls are thinner in ammonites than in nautiloids so the complexity of the suture line does nothing to add to the crush strength of the shell.
In a 53 page section, Heteromorph presents the heteromorph ammonites of the Triassic, Jurassic and Cretaceous. Each section has introductory information followed by a two page diorama reconstructing the environment. The two pages following the diorama duplicates the diorama but adds a key to identify all of the fauna represented. The Triassic had only very few and very small heteromorphs so the fossil photos are restricted to the introductory page. The Jurassic had more heteromorphs and the fossil photos fill three pages after the dioramas. The Cretaceous section is the largest. Two pages of taxonomy follow the diorama pages and then the fossil photos are subdivided into the chronologically arranged stages of the Cretaceous in the next 26 pages.
In a major section on lifestyle, Grulke discusses the many aspects of the heteromorphs from where they lived, feeding, breeding, sexual dimorphism, and even being food for others. The logical comparisons to modern Nautilus are considered heavily since both types are externally shelled cephalopods. Some researchers are looking differently at the heteromorph ammonites with thoughts that they may have had a lifestyle like the modern Spirula. Comparison to Spirula, which has an internal coiled chambered shell, has made some wonder whether heteromorphs could have had their shell exterior either wholly or partially covered by the mantle. Healed damage to the shells on some specimens of Ptychoceras (one of the paperclip shaped heteromorphs) may provide evidence for this theory. As for sizes, some of the largest planispirally coiled ammonites are pictured in Heteromorph; the largest is Parapuzosia seppenradensi at 1.792 meters in diameter. The largest heteromorph ammonite, a Moroccan Moutoniceras, is 1.47 meters tall.
I was concerned about a statement made in the lifestyle chapter pertaining to the early evolution of nautiloids. Grulke made the statement, “ During the Silurian period, straight-shelled nautiloids started developing slightly curved shapes and some started coiling ever tighter.” (p. 103) My concern with this statement is that in our local Ordovician (Katian) rocks we have Trocholites in the Kope and Charctoceras in the Richmond that are both completely coiled nautiloids. We also have numerous partially coiled genera. The specific source for Grulke’s statement was not stated here but I assume it to be the earlier reference to the 2011 work by Kröger, Vinther, and Fuchs. I investigated this original source thanks to Holly Prochaska of U.C. This paper uses molecular clock data along with fossil data to investigate cephalopod origins and evolution. Their analysis indicates that the last common ancestor of the lineage that led to modern Nautilus diverged in the late Silurian. This does not appear to state that the nautiloidea originated in the late Silurian. From graphical representations in this paper it appears that the stem group leading to the nautiloidea diverged in the late Cambrian/early Ordovician. Kröger, et. al., state that the “fossil record indicates a divergence between these hypothesized ancestors of Nautilus and the straight ancestors of coleoids [octopus, squid, etc] by the early Paleozoioc (~480 Ma).” It is my opinion that Grulke misinterpreted or inadvertently misrepresented the conclusions from this paper.
A 29 page chapter presents the top localities in the world where heteromorph ammonites are collected. A number of the sites mentioned are being commercially collected as a local industry to boost the economy in depressed areas, for example, Morocco, Madagascar, and Russia. This moves a lot of material into the collector’s and decorative markets. That is good news bad news. In the case of Madagascar, most of what is exported are locally worked - cut, polished, ground down - to suit what is perceived as market demands so it is harder to get an unaltered specimen. Morocco and Russia have enjoyed the market demand as well and produce outright fakes to supplement their production.
Grulke provides a lesson for those who would like to forget the history of paleontological studies in the chapter “From Old to New.” He runs through a brief account of the history of the geological sciences and emphasizes that virtually all of the earliest collectors and savants who studied the fossils were, by modern definitions, amateurs. Grulke relates the story of a mid-twentieth century collector, Louis Maurel of Barręme, France, who amassed a huge collection of ammonites and heteromorph ammonites. Maurel kept a detailed log of his discoveries so that everything is well documented. Grulke shares some of his log entries including one from April 22, 1967: “Four geologists from Marseille came to visit. They plan to ban access to many fossil sites in the region. Making geology a reserved field is a questionable idea, even unacceptable, because nature is a common property. It belongs to the rich as well as the poor, to the learned as well as the uneducated, to the old man as well as the child.” Grulke goes on to discuss the more recent attempts to kill commercial collecting. In one of the best arguments I have seen in print for the misguided restrictions to fossil collecting, Grulke states, “ Beneath all this sits an inescapable financial reality - the academic community will likely never again have sufficient funds to recover, prepare and display fossils that are exposed by regular weathering, storms or commercial mining. The days for idealism have passed. Without amateur collectors and commercial dealers, the bulk of newly exposed or discovered material would be lost to mankind, not just science - a view reflected in the US Paleontological Society’s code of ethics: ‘The principal importance of fossils is for scientific, scholarly, and educational use of both professionals and amateurs...to leave fossils uncollected assures their degradation and ultimate loss to the scientific and educational world through natural processes and erosion’.”
Additional chapters in Heteromorph include one highlighting Grulke’s personal favorite odd heteromorph ammonites and even some modern heteromorph gastropods. The evolution of scientific illustration is chronicled from beautiful engravings to more modern photographs that many times are not as impressive. Grulke does allow that the early engravings were often enhanced beyond what the actual specimen revealed. These early works of art, like many early natural history illustrations, sadly are being cut from the original books and framed as art objects.
In the final chapter of Heteromorph Grulke shows the transformation from “stone to sculpture.” A two page photo of a single death assemblage from Morocco, in my opinion, reveals what has to be the most amazing paleontological object ever displayed. The final piece is 2 meters by 4 meters and weighs close to 2500 kg (that’s over 6 ft x 12 ft and 5,500 pounds). The prep work alone took ten years. Over 45 species of ammonites and heteromorphs including some new to science are exposed in the work.
One of the more impressive aspects of the specimens illustrated in Heteromorph is the profusion of heteromorph ammonites with long delicate spines. As Grulke explains, the preparation techniques of even twenty years ago could not preserve the spines. New technology and skilled preparators with new techniques now allow these fossils to be seen in their original beauty. Readability - High school to undergrad.
Readability - High school to undergrad.
On the Upside - Excellent photographs of beautiful specimens. Scientifically accurate descriptions and analysis. Reasonably priced.
On the Downside - While reference is made to specific work by paleontologists studying ammonites, e.g., “... Jurassic Spiroceras orbignyi could likely have been suited for a lifestyle amongst algal mats in shallow water (Dietl 1978) ...” (p. 109), no detailed citations are provided. Finding the original source becomes difficult. Considering the effort that is made to provide a well researched scientifically accurate work, this omission is perplexing.
Overall Rating - This is well worth procuring for the personal library of anyone interested in ammonites in general and the heteromorph ammonites in particular.