Evolution of the Coelacanth Saga

This week Andrew J. Wendruff and Mark V. H. Wilsonof the University of Alberta made a new contribution to the evolution of the coelacanth saga in the paper “A fork-tailed coelacanth, Rebellatrix divaricerca” published in the Journal of Vertebrate Paleontology.

Since the discovery in England by Louis Agassiz in 1839, the coelacanth has played a pivotal role in the history of evolution.

For Agassiz, the coelacanth fossil record pointed to “a correspondence between the succession of Fishes [evolution of fishes] in geological times”. Reflecting on Agassiz findings, Charles Darwin wrote in The Origin of Species: “this doctrine of Agassiz accords well with the theory of natural selection.”

At the time, the coelacanth was thought to be a species bridging the transition of life from water to land. This conclusion was primarily based on the limb-like structure of the fins; a structure on the way up from a fin for swimming and a foot for walking. The coelacanth was touted as fossil record “missing link” evidence for evolution.

The coelacanth was embedded into biology text books as the “missing link” evidence for evolution.

In 1938, however, an unusual fish was caught in the coastal waters of South African. In examining the “five foot long, a pale mauvy blue with faint flecks of whitish spots”, local curator Marjorie Latimer in noting “four limb-like fins and a strange puppy dog tail”, concluded that the fish must be one of the last remaining of the extinct coelacanths.

The catch resembled Agassiz’s collection of fossilized coelacanths and was named after the curator: Latimeria chalumnae.

Weighing 126 pounds, the live fish was hailed a scientific sensation. Since this first discovery, the coelacanth is has been found alive and well living at a depth of one thousand feet and deeper with a territorial range from South Africa to Indonesia.

With more than a fossil available for study, the reality question came – is the coelacanth actually a missing link? In comparing the fossilized form to the live form, the coelacanth was found to be much different from what was originally expected.

On examination, scientists found the coelacanth fin to simply be a fin: not a moving-on-up transitional form between a fin and a foot. The fins were not found to be similar to any hand or foot capable of walking on land.

Rather than the textbook example of a “missing link”, the status of the original coelacanth has evolved and is now to be considered simply as a unique and distinct species of lobe-finned fish.

Not only were the fins not on their way to a foot, the internal organs weren’t on the way to land either.

Paleontologist Barbara Stahl concluded in Vertebrate History: Problems in Evolution, “The modern coelacanth shows no evidence of having internal organs preadapted for use in a terrestrial environment.”

Robert L. Carroll, paleontologist of McGill University, concluded “We have no intermediate fossils between Rhipidistian fish [coelacanth] and early amphibians.” “Unfortunately”, Carroll further explained, “not a single specimen of an appropriate reptilian ancestor is known prior to the appearance of true reptiles. The absence of such ancestral forms leaves many problems of the amphibian—reptile transition unanswered.”

This week’s announcement by Wendruff and Wilson of a new coelacanth found on rocky slopes in the Hart Ranges of Wapiti Lake Provincial Park, British Columbia, undermines Darwin’s theory of “slight, successive’” changes. The new coelacanth finding, rather than demonstrating transitional characteristics, revealed stark differences−not transitional changes.

Since the new coelacanth “is unique among coelacanths in its possession of a bifurcated caudal fin, reduced segmentation of fin rays, and fusion of caudal fin elements”, Wendruff and Wilson conclude that the new finding “raise[s] questions about long-held ideas concerning the evolution of coelacanth body forms and the mode of locomotion.”

Due to the uniqueness, Wendruff and Wilson were forced to develop a new family name for this coelacanth−Rebellatricidae. The full name of Rebellatrix divaricerca was given, even though R. divaricerca is the only species in the entire family.

Rebellatrix is dramatically different from any coelacanth previously known, and thus had undergone significant evolutionary change in its ancestry,” Wendruff said.

The addition of R. divaricerca to the confusing coelacanth saga further undermines the concept of a “succession” of evolutionary transitional forms envisioned by Agassiz and Darwin. Rather than filling in the gaps, R. divaricerca has unveiled yet another unresolved gap in the fossil record.

Evidence in the fossil record for the evolution of life from water to land remains a mystery within the realms of science. In 2004, Henner Brinkman in the Proceedings of the National Academy of Science succinctly noted: “The colonization of land by tetrapod ancestors is one of the major questions in the evolution of vertebrates”.

The evolution of available coelacanth evidence since 1839 continues to raise more questions than answers for the evolution industry. New fossil record findings from the R. divaricerca discovery undermine, rather than underscore, the evidence for the “slight, successive” evolutionary changes once envisioned by Darwin.

Even in the book Why Evolution is True, Jerry Coyne never refers to the coelacanth as evidence for evolution. Reason: evidence for evolution is not found in the coelacanth.

Evolution, once a theory in crisis, is now in crisis without collaborating consistent evidence or even a comprehensive theory.

The evolution of the coelacanth saga continues. Evolution continues only as a philosophy – not as a scientific fact.

 

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