Coelacanth

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Coelacanth
070801 coelacanth2.jpg
Scientific classification
Kingdom Information
Kingdom Animalia
Phylum Information
Phylum Chordata
Class Information
Class Sarcopterygii
Sub-class Actinistia
Infra-class Coelacanthimorpha
Order Information
Order Coelacanthiformes
Family Information
Family Latimeriidae
Genus Information
Genus Latimeria
Species Information
Species L. chalumnae
L. menadoensis
Population statistics
Coelacanth range.png
Population 1,000 est.
Conservation status Critical

Coelacanth is an order of lobe-finned fishes related to lungfishes and represented by two living species, Latimeria chalumnae and Latimeria menadoensis, and according to evolution they were thought to be extinct until one was caught off South Africa in 1938. It is considered to be a critically endangered species with an estimated 1,000 animals alive today.[1] There is little evidence to suggest that this species of fish has been around for over 100 million years as is falsely claimed by evolutionists.

Contents

Description

Coelacanths are relatively-large fish, with an average length of just over a meter, and a weight of 98 kilograms; adult females are larger than males. The species L. chalumnae from Madagascar are blue in color with varying spots of white, while the species L. menadoensis from Indonesia are brown. Their scales are large in size and are thought to serve to some degree as body armor. Caught specimens, as well as fossilized remains, indicate coelacanths give birth to live young rather than deposit eggs.

With the exception of the dorsal fin, all other fins are "lobed", that is the fin proper is mounted to a stalk, the flexability of which enables the coelacanth to hover in-place or swim in all directions, including backwards or upside-down [1]. The fins themselves are "ray-finned", with an internal structure similar to skates, rays, and sharks.

Evolutionary claims

Age

According to the theory of evolution, scientists claim the fossil record of coelacanths now extends from what they call the early Devonian (410-415 million years ago)[2] to the late Cretaceous (about 80 million years ago).[3], and until 1938 claimed that these fish became extinct some 65-75 million years ago.[4] During that year Marjorie Courtenay-Latimer, curator of a museum in East London, South Africa, found a curious fish in a trawler's catch just before Christmas, and sent a description of the animal to ichthyologist James Leonard Brierley Smith, who identified the fish as a coelacanth in February, 1939, naming it Latimeria chalumnae after its discoverer and the Chalumna River near where it was caught. Since 1938 about 200 coelacanths have been caught, the majority in the Comoros Islands.[4]

Tetrapod ancestry

The lobed fins unique to the coelacanth have inspired evolutionists to declare that they were the ancestors of tetrapods: amphibians and reptiles. As detailed in the journal Evolution & Development (July/August 2007), a fossil recovered in Wyoming of the pectoral fin of the coelacanth Shoshinia arctopteryx [2] indicated to scientists that:

"The fossil record provides unique clues about the primitive pattern of lobed fins, the precursors of digit-bearing limbs. Such information is vital for understanding the evolutionary transition from fish fins to tetrapod limbs, and it guides the choice of model systems for investigating the developmental changes underpinning this event. However, the evolutionary preconditions for tetrapod limbs remain unclear. This uncertainty arises from an outstanding gap in our knowledge of early lobed fins: there are no fossil data that record primitive pectoral fin conditions in coelacanths, one of the three major groups of sarcopterygian (lobe-finned) fishes. A new fossil from the Middle–Late Devonian of Wyoming preserves the first and only example of a primitive coelacanth pectoral fin endoskeleton. The strongly asymmetrical skeleton of this fin corroborates the hypothesis that this is the primitive sarcopterygian pattern, and that this pattern persisted in the closest fish-like relatives of land vertebrates. The new material reveals the specializations of paired fins in the modern coelacanth, as well as in living lungfishes. Consequently, the context in which these might be used to investigate evolutionary and developmental relationships between vertebrate fins and limbs is changed. Our data suggest that primitive actinopterygians, rather than living sarcopterygian fishes and their derived appendages, are the most informative comparators for developmental studies seeking to understand the origin of tetrapod limbs."[3]

However, certain details have been overlooked or ignored. The first is the obvious fact that current science is still unclear as to its own theories regarding the history of the coelacanth, with the author of the journal article (Matt Friedman, University of Chicago) admitting that "the evolutionary preconditions for tetrapod limbs remain unclear", yet claiming the Wyoming fossil has a similar pattern to fish-like relatives of land vertebrates.

The second detail ignored is the fact that all terrestrial vertebrates found in the fossil record have their limbs fully-developed and attached to the backbone, and the fossil remains of coelacanths are clear in that the fins were independent of the backbone. The enormous changes the fish would also need to make when living on dry land (hearing, sight, and smell; development of lungs, kidneys; change of skin structure) have also not been found in the fossil record. Barbara J. Stahl, an evolutionist and palaeontologist, wrote in her book Vertebrate History: Problems in Evolution

"Although the relationship of the rhipidistians to the amphibians will be discussed in greater detail in the next chapter, it should be said here that none of the known fishes is thought to be directly ancestral to the earliest land vertebrates. Most of them lived after the first amphibians appeared, and those that came before show no evidence of developing the stout limbs and ribs that characterized the primitive tetrapods." (Stahl, p.148)

An article published in the scientific journalNature regarding the completion of the genome sequencing of the African Coelacanth suggested that it is most like the closest living relative to primitive tetrapods. The researchers have used these findings to speculate that ceolacanth DNA may be able to explain the evolutionary steps which allegedly brought fish out of the ocean and on to dry land.[5]

References

  • Stahl, Barbara J. Vertebrate history: Problems in Evolution, Dover: New York (1985)

External links

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