The Tale of a Really Big Dinosaur

If you have seen any of the numerous shows on television about current work on dinosaurs, you'll probably be familiar with the name Seismosaurus (This is not to be confused with other recent discoveries of Supersaurus or Ultrasaurus). David Gillette and Columbia University Press published Seismosaurus the Earth Shaker in 1994 and we'll review it this month. Retail price on this hard bound volume is $39.95.

This book differs considerably from last month's book The Little Dinosaurs of Ghost Ranch both in form and style. Seismosaurus... is a large 9 x 12, slick paged, color photo illustrated, book of 205 pages. Although both books are directed to the general reader, I'd say that this one is a bit more so. Seismosaurus... contains more lengthy explanations of each aspect covered.

Gillette does a good job in conveying the tremendous amount of work involved in vertebrate paleontology from initial discovery, permits to excavate, and analysis of the fossils. Seismosaurus halli, or Sam as nicknamed by the author, is a new genus and species of late Jurassic sauropod. It is known from the skeletal remains of a single specimen which included a few neck vertebrae, the back vertebrae with most of the ribs, the hips, and a good portion of the tail. One of the largest vertebrae near the hips was six feet high.

Gillette devotes an entire chapter to the naming of the new genus Seismosaurus. Why so much space? Gillette takes time to discuss similarities and differences between this and other related dinosaurs to show the analysis required before a new genus or species can be announced. A later chapter describes the evolutionary relation of Seismosaurus to other sauropods and yet another chapter speculates on which was the longest and heaviest. Within these chapters Gillette presents his thoughts on Supersaurus and Ultrasaurus; it is obvious he feels that both genuses are described on insufficient material and that they could easily be large individuals of known species.

I think many will be interested in the extensive coverage of hi- tech methods used to locate the remains before digging! Some of the methods, such as using seismographic analysis, have been shown before on the PBS dinosaur specials. Other methods like using ground penetrating radar may be new to the reader as I'm sure proton free-precession magnetometry will. Don't be alarmed, the explanation and applications of these methods are all very simply presented.

Gillette devotes a twenty-eight page chapter to "Mysteries of Fossilization". Herein he takes exception to the long taught explanation of petrification as a "molecule by molecule replacement of original bone with minerals". I found this to be a fascinating chapter with very convincing arguments. One might wonder why such a chapter was important to this book. Part of the hi-tech analytical methods used on the fossil included a chemical analysis of the fossil bone; this testing showed that Sam's fossils contained original bone mineral. Gillette speculates that other dinosaur fossils may also contain original bone mineral as well.

Gastroliths consume a full chapter. These are the stomach stones used by some animals, including birds, that help grind coarse food in the digestive system. Many discoveries of groups of smooth stones have been found and reported to be gastroliths. Most of them have not been associated with skeletal remains. In the case of Sam, the stones were found within the extent of the fossil skeleton in the correct anatomical position to be true gastroliths. This twenty page chapter goes into quite some detail to present this evidence.

All in all I found this to be an easily read and enjoyable book. I recommend it to dinosaur lovers who want to learn more without having to strain through the highly technical literature of the professional paleontologist.

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