420-million-year-old fish with four legs that was thought to be extinct has been found in Africa (1 Viewer)

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Cold Ethyl

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Several shark hunters stumbled upon a previously unknown population of coelacanths, a 420-million-year-old 'fossil fish' that was once thought to be extinct.

The discovery was made in the southwestern part of Madagascar in the Indian Ocean.

The remarkable find, first outlined by Mongabay News, stems from the result that the shark hunters were using gillnets looking for the sharks, only to turn up the ancient fish.

Coelacanths have four fins that act like limbs and were once given the moniker 'Old Fourlegs.'

They have eight fins in total -- two dorsal fins, two pectoral fins, two pelvic, one anal and one caudal fin.

A recent study published in the South African Journal of Science notes that gillnet fishing, which really came of age when hunting for sharks ratcheted up in the 1980s may severely impact the remaining coelacanths population.

'The advent of deep-set gillnets, or jarifa, for catching sharks, driven by the demand for shark fins and oil from China in the mid- to late 1980s, resulted in an explosion of coelacanth captures in Madagascar and other countries in the Western Indian Ocean,' the researchers wrote in the study's abstract.

These advanced nets can reach the depths where coelacanths swim and gather, between 330 and 1,600ft (100m and 300m).

The study's lead author, RESOLVE sarl Managing Director Andrew Cooke, told Mongabay News it's possible that more than 100 coelacanth could have been caught off the coast of Madagascar in recent decades.

'When we looked into this further, we were astounded [by the numbers caught]… even though there has been no proactive process in Madagascar to monitor or conserve coelacanths,' Cooke said.

According to a September 2020 list from RESOLVE, at least 34 specimens have been collected between 1987 and 2019.

In the study, Cooke and the other experts believe Madagascar is the 'epicenter' of the coelacanth distribution.

'The presence of populations of the Western Indian Ocean coelacanth (Latimeria chalumnae) in Madagascar is not surprising considering the vast range of habitats which the ancient island offers,' they wrote in the study.

They continued: 'The discovery of a substantial population of coelacanths through handline fishing on the steep volcanic slopes of Comoros archipelago initially provided an important source of museum specimens and was the main focus of coelacanth research for almost 40 years.'
As such, the experts note their findings emphasize 'the importance of the Onilahy marine canyon in southwest Madagascar as an especially important habitat and provides the basis for the development of a national program of research and conservation.'

However, Tony Ribbink, former head of the African Coelacanth Ecosystem Program (ACEP), said it's not quite clear that Madagascar plays such a vital role to the coelacanth population.

In 2015, scientists determined the coelacanth, also called Latimeria chalumnae, had a lung.

The lung is no longer functional, but provides clues about how its ancient relatives lived 410 million years ago.

Latimeria doesn't have a 'calcified lung' like its ancestors.

However, X-rays show that the species has a well-developed, potentially functional lung in early-stage embryos.

As it grows, the lung becomes functionless, becoming of no use to the living species, which — like all other fish — breathes using gills.
'It would be extremely valuable if they also considered a competing hypothesis that the large number of canyons, many of which are very big, deep and extensive, running along the northern Mozambique coast from where the Sofala Banks end northwards to the southern part of Tanzania (just south of Mtwara) offer the most extensive area of suitable habitat for coelacanths,' Ribbink said in an interview with Mongabay.

This unexplored continental area may well be the epicenter of coelacanth distribution. This area has not been studied, however and, until it is eliminated as a plausible competing hypothesis, the work of the authors will remain hypothetical.'

Coelacanths were initially thought to be extinct until 1938 when it was rediscovered off the South African coast.

They can reach up to 200 pounds in mass and live for 48 years according to National Oceanic and Atmospheric Administration and are known for their bizarre appearance.

The bony fish can reach up to 6.5ft in length and have spotted scales throughout the body.
Known scientifically as Latimeria chalumnae, coelacanth are listed under the Tanzanian distinct population segment (DPS) and are considered threatened under the Endangered Species Act




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ArmageddonWatcher

Forum Veteran
So they did not really change within' 420 million years? Hmm, why didn't they evolve over time by natural selection? They are not sharks, who are believed to be in stasis because of their perfect shape and function and place at the top of the food chain, right?
 

ArmageddonWatcher

Forum Veteran
So they did not really change within' 420 million years? Hmm, why didn't they evolve over time by natural selection? They are not sharks, who are believed to be in stasis because of their perfect shape and function and place at the top of the food chain, right?
Damn, still not one single intellectual reply?
Where are the brilliant minds of GG when you need 'em? 😉
 

Nihilianth

Forum Veteran
So they did not really change within' 420 million years? Hmm, why didn't they evolve over time by natural selection? They are not sharks, who are believed to be in stasis because of their perfect shape and function and place at the top of the food chain, right?
Thats...not how evolution works...

Yes. Sharks are probably about as close to the perfect fish design as you can get. But that doesn't mean every water-based species will eventually evolve into a shark. Jesus fucking christ.
 

ArmageddonWatcher

Forum Veteran
Thats...not how evolution works...

Yes. Sharks are probably about as close to the perfect fish design as you can get. But that doesn't mean every water-based species will eventually evolve into a shark. Jesus fucking christ.
Dear lord, how Jesus knows you missed my point. 😉

If we reckognise sharks to probably being close to the perfect fish design (there are scientific, valid reasons to assume that), and Coelacanth doesn't come close to such a shark-like design, why didn't Coelacanth change over such a long time. Is it also close to a perfect design?

If no, it should evolve, but we can see with our own eyes by direct observation that it didn't.

If yes, why is it close to perfect? By what threads? Are there many other "perfect" threads than those of sharks? And, theoretically speaking, with so many possible near-perfect threads, wouldn't most fish be near perfect just by being what they are? Taking this point one step further, if there are several possible perfect designs, what is the point of change, other than micro-evolution (change of color, shorter/longer fins), or devolution (loss of vision, color, bones)?

You were the one that stated "Thats [sic]...not how evolution works..."

Now, please...answer my questions, enlighten me.
 

Nihilianth

Forum Veteran
Dear lord, how Jesus knows you missed my point. 😉

If we reckognise sharks to probably being close to the perfect fish design (there are scientific, valid reasons to assume that), and Coelacanth doesn't come close to such a shark-like design, why didn't Coelacanth change over such a long time. Is it also close to a perfect design?

If no, it should evolve, but we can see with our own eyes by direct observation that it didn't.

If yes, why is it close to perfect? By what threads? Are there many other "perfect" threads than those of sharks? And, theoretically speaking, with so many possible near-perfect threads, wouldn't most fish be near perfect just by being what they are? Taking this point one step further, if there are several possible perfect designs, what is the point of change, other than micro-evolution (change of color, shorter/longer fins), or devolution (loss of vision, color, bones)?

You were the one that stated "Thats [sic]...not how evolution works..."

Now, please...answer my questions, enlighten me.
Ugh, you completely misunderstand evolution and the theory of natural selection.

Yeah, a shark IS perhaps a better "design" than a coelacanth. That doesn't mean that a coelacanth isn't a viable species. Especially within its own niche environment.

You completely missed my point. My point, is that there have been trillions of different species that has existed, and billions that currently exist. Some species are "better" than others. Of there were such a thing as a "perfect" species (there isnt!) Evolution doesn't guarantee that life would go in that direction. Hence: my snarky reply.

Also, evolution can progress a species faster than others. And a quick progression of a particular species may halt altogether for a very long time.

The biggest driving factor for evolution is changing environmental conditions. Considering the coalacanth is an excellent design for a fish that makes its home in the depths of the oceans where not even sharks can reach, and where environmental conditions hardly changes at all....evolution would inevitably come to a practical standstill.

They don't really have any natural predators, and they can live almost as long as a human. (Another big factor of speed of evolution: the lifespan of a generation. The lower a species' lifespan, the faster they can evolve. That's a big reason why there are thousands of different species of moth, but only 5 species of apes. There are about 79 generations of moth per 1 generation of humans.)
 
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