Paleontologist Keith S. Thomson’s Living Fossil, although still a “popular” work, is more technical than Samantha Weinburg’s A Fish Caught In Time; Thomson is also handicapped by publishing before (1993) the second coelacanth species was discovered in Indonesia (1997) and before the discovery of another population off Tanzania (2003). The first third of Living Fossil covers the same ground as Wienburg; the initial discovery in 1938, the second specimen in 1953, the various personality quirks of the discoverers, and so on. For the remainder Thompson goes over what’s known of the biology of coelacanths, including his own adventures in acquiring a fresh frozen specimen from the Comoros. (The fish was packed in a crate addressed to “Dr. Thomson, Peabody Museum, USA” and handed off to a passing fruit boat – bound for Marseille. The ship captain approached the US Consul in Marseille asking what he was supposed to do with; he wanted to shut down his freezers for cleaning. After considerable international phone calling, the fish arrived at Yale still frozen. The letter from the Comoros informing Thomson that a coelacanth was on the way arrived much later).


As mentioned, Thomson’s discussion of the geographical range of coelacanths is now obsolete; at the time he was writing the only known population was in the Comoros (other than the initial discovery off South Africa). There have since been catches in Indonesia and various places on the east African coast. He raises the interesting question, though, which still applies – before Latimeria, the last known coelacanth fossils were from Cretaceous shallow fresh water deposits in Europe; the living species is from deep marine water in the Indian Ocean. What were coelacanths doing in the meantime? Thomson’s answer hinges on the fact that deep marine deposits are always rare in the stratigraphic record; there were probably deep marine coelacanths all along but they just never showed up as fossils. Thompson also critiques some of the speculations based on the Comoros specimens – most were caught between January and March at depths from 150 to 250 meters so it was assumed that was coelacanth habitat. As it turns out, this is when Comoro fishermen do their deep water fishing – it’s when the water is calm offshore – and since they fish with handlines, 150-250 meters is about all they can handle. Thus the fishing records really don’t say that much; they’re where people fish for coelacanths, not where coelacanths actually live.


The biology of the animal is fascinating; genetic studies have made the point that a coelacanth is more closely related – in terms of genetic distance – to a cow than it is to a salmon. It’s certainly a fish on the outside, but that’s a function of where it lives, not what it’s like inside. Coelacanths have a rostral organ – nobody is quite sure yet what it does but the best bet is it has to do with positioning. Submersible observations of coelacanths show positioning is a strong point; the animal swims with its lobe fins (including the little lobe in the middle of the tail) and can swim in any direction in any position – upside down and backwards if that’s what it needs to do. It has an intercranial joint – the skull is hinged in the middle – and that facilitates its hunting tactics, which are to approach a target (again, in any direction and orientation) and suck the prey in with a sudden gulp. It has a hollow, oil-filled notochord, which compensates for relatively small and weak vertebrae. And it has blood isotonic with sea water, a characteristic it shares with elasmobranch fish; coelacanths concentrate urea and trimethylamine oxide in their blood to a level that would be lethal to most vertebrates and use these to make their total osmotic blood concentrations the same as sea water. (Marine actinopterygian fish have blood osmotic concentrations less than sea water and dispose of excess salt through specialized glands in their gills; freshwater fish have mechanisms to concentrate salt and produce copious quantities of very dilute urine to get rid of excess water).


A light read despite some fairly technical discussion of fish physiology; Thomson is a good explainer. Badly needs a second edition, though, to account for all the coelacanth discoveries in the last 20 years. Well referenced; no photographs but good line drawings, graphs, and tables. ( )

On December 22, 1938, Marjorie Courtney-Latimer, curator of the small natural history museum of East London on the southeastern tip of South Africa, was called to the docks by a friendly trawler captain. Courtney-Latimer had a standing arrangement with local fisherman. They would call her if they discovered any unusual specimens so she could add them to the museum. She was stunned by what she saw on the deck. This fish was unlike anything seen before. It was about 5 feet long, a very strange blue color, and was reported to have been still alive when pulled out of the net; extremely unusual for a fish at the bottom of the net which would have normally asphyxiated. The fish's anatomical construction was also peculiar. It had, in addition to a double tail J two strangely paired fins in front which flopped in all directions very much like legs.

This discovery was to become one of the most exciting in recorded zoological history. Keith S. Thomson, a renowned biologist, tells the fascinating story of this discovery and the research on the coelacanth (pronounced seal-uh-canth.) Fortunately, Courtney-Latimer sent the fish to James L. B. Smith, a professor of chemistry, but a lover of fish who after the war became a celebrated ichthyologist. Smith thought he recognized the fish as a coelacanth, known previously only from the fossil record and thought to have been extinct for many millions of years. The coelacanth was most important, as it was a close relative of an ancient ancestor of land-dwelling vertebrates. Thomson defines "living fossil" (an apparent oxymoron) as the living representative of an ancient group of organisms one would expect to be extinct, formerly distributed over a large geographical area, but now restricted and probably rare or uncommon. The Australian lungfish is an example of living fossil, as is the horseshoe crab. Living fossils are usually quite primitive in comparison with other organisms. (Do you suppose the KKK could be considered a living fossil?) One particularly curious feature about coelacanths is they have only been found near the Comores Islands, a very recent geological structure dating back only some 7,000-8000 years. How did the coelacanths survive if they need the kind of environment that only seems to surround relatively recent geological structures?

This book is a mesmerizing account of the discovery and the tawdry battle among scientists to get their hands on specimens for research. It's also a most elucidating revelation of the scientific method: the building of an hypothesis, testing, refutation, and discarding those theories which are erroneous. Ironically, science now finds itself in the awkward position of perhaps causing the extinction of a unique and valuable species precisely because it is so interesting. The fish has no commercial value in the usual sense, and local fisherman only search for it now because of the relatively enormous sums scientists are willing to pay to obtain one. Some scientists, usually the ones who already have a specimen,) worry that this predatory interest will reduce the population to a point where it will no longer be able to reproduce. ( )

If biology interests you, this is an interesting read. Written in such a way as to be interesting to the non-scientist.
Reading level: medium
Suitable for: anyone