The Coelacanth An Odd Fish

byEric Ribbens, Western Illinois University,

based on a case by Robert H. Grant

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©SAIAB

Marjorie Courtenay-Latimer(born February 24, 1907)

Marjorie was the curator of the East London museum in South Africa.

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December 23, 1938

“My friend, Capt. Hendrick Goosen, had just returned from a trawling trip around the mouth of the nearby Chalumna River. Hendrick often calls on me when his catch is substantial so that I can look and see if there may be anything of scientific interest for the museum. More often than not, I find nothing but a pile of malodorous fish.”

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December 23, Continued...

“… a strange bluish fin poking through the pile caught my eye. It was like no fish fin I had ever seen in all my years at the museum.”

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Discussion Question

What do you see that might have led Ms. Courtenay-Latimer to believe that such a fish might be special?

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What did Marjorie see?

• Marjorie wrote: “The Captain and I shoved the other fish off the top of the pile to uncover the owner of the odd fin. There it lay before me, the most beautiful fish I had ever seen, five feet long, and a pale mauve blue with iridescent silver markings.”

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Discussion Question

• Imagine you are Marjorie Courtney-Latimer. You have found an unusual fish, 127 lbs. and 5 feet long. It’s a really hot day, and you don’t really know that much about fish, so you don’t know if this is really a significant find or not.

• What should you do?

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CQ#1: What do you think she did?

A: Sketched the fish and took some measurements.

B: Asked the captain to have the fish delivered to the museum.

C: Took some pictures with a camera and collected a DNA sample.

D: Loaded the fish into the back of a taxicab.

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What should she do?

• Marjorie wrote: “I am no fish expert, but I had the strange feeling that somehow this fish was special. I decided to take the fish with me, and after a heated discussion with the taxi driver, we stuffed the huge fish into the backseat of the cab and headed off for the museum…”

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CQ#2: When Marjorie showed the fish to the museum director, he:

A: Said it was just an ordinary fish.

B: Became excited and told her to find a fish expert to look at it.

C: Asked her to please remove that big dead fish before it began to smell.

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What next?

• The next day Majorie wrote in her diary: “Could not believe that the director of this museum would not even consider the bizarre appearance of this fish as unique. To think, he said it was just another rock cod! I feel that it definitely resembles some of the pictures I found in Fossil Fishes of the World.”

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Here’s a Rock Cod:

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And here’s Marjorie’s fish again:

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©SAIAB

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Rock cod

Marjorie’s fish

What do you think?

• Was it a rock cod?

• What differences or similarities do you see?

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Continuing from her diary:

• “This is the first time I’ve wished my expertise lie in fish instead of birds. I must contact J.L.B. Smith in Grahamstown.”

• J.L.B. Smith was an expert about fish.

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©SAIAB

Waiting…

But Dr. Smith had gone on vacation, and so Marjorie had the decomposing fish mounted by a taxidermist. The picture above is a drawing she sent Dr. Smith. After the mounting, she received a telegram on January 3rd from Dr. Smith:

MOST IMPORTANT PRESERVE FISH AND GILLS = FISH DESCRIBED.

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©SAIAB

February 16, 1939

• “Dr. Smith arrived today and has caused quite a stir. He positively identified the fish as a coelacanth, a fish that was thought to have been extinct for about 70 million years! My hunch was correct! We have found a living fossil. Dr. Smith said that this fish and its relatives were swimming in seas and lakes when T. rex walked the Earth! Cannot begin to describe my excitement.”

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A Fossil Coelacanth

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Dr. Smith and the coelacanth

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©SAIAB

CQ#3: The youngest coelacanth fossil found has been dated to 70 million years ago. Why was there a gap of 70 million years in the coelacanth’s fossil record?

A: Coelacanths became extinct 70 million years ago, and then re-evolved.

B: Coelacanths may have become much rarer 70 million years ago.

C: The fossils must be out there, they just haven’t been found yet.

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Discussion Question

• Why was Dr. Smith excited, and why would a scientist interested in evolution be excited? (Think again about the structure of the fish.)

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Discussion Question

• It’s been argued that the coelacanth is a “missing link”. Look at the phylogenetic tree on the next slide and explain why it has been described that way.

• It’s also been argued that because it is alive today it’s not a missing link. What do you think?

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Where are the Lobe-Finned

Fishes?

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CQ#4: Is the coelacanth a “missing link”?

A: Yes

B: No

C: Missing links are only found in human evolution

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EvolutionThis diagram shows that the coelacanth is more closely related to mammals and other more derived vertebrates than the ray-finned fishes are. This means that coelacanths have more derived characteristics (fewer ancestral) than the ray-finned fish do.

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CQ#5: If coelacanths are more derived, why are ray-finned fish more common?

A: Ray-finned fish are actually the more derived. The diagram is wrong.

B: Derived traits don’t mean that those organisms are more abundant.

C: Coelacanths haven’t been found in abundance yet, but they must be.

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CQ#6: Did the captain and his crew catch the LAST coelacanth?

A: YesB: No

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Discussion Question

• If you were a scientist interested in coelecanths, what would you do next?

• If there are more coelacanths, why is it important that they are found?

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Fun Facts• Ms. Courtenay-Latimer, Dr. Smith, and their coelacanth became

overnight celebrities. For a one-day-only showing of the coelacanth in East London in 1939, 20,000 visitors reportedly showed up.

• Fossils of the class of fish to which the coelacanth belongs appeared some 400 million years ago, mostly in fresh water environments on all continents except Antarctica.

• The fish specimen was named Latimeria chalumnae in honor of Ms. Courtenay-Latimer and the area in which it was caught (Chalumna River mouth).

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Marjorie and Coelacanth

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More Fun Facts• At the time of the discovery, it was thought that the coelacanth

may have been the fish species that led to the first land amphibian, using its fleshy limbs to walk onto land.

• Another living coelacanth was not found until 14 years later. It was caught by a fisherman in the Comoros Islands hundreds of miles north of the Chalumna River. Its internal organs were preserved, leading to many interesting insights into its biology.

• Based on recent and ongoing observations of coelacanths off the Comoros, scientists know that coelacanths live about 180 meters deep in caves, bear live young, and live for about 60 years.

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34©SAIAB

Discussion Question

• Comoros fisherman had known about the fish for years, calling it “Gombessa.”

• If native people knew about coelacanths but the western world did not, did Marjorie Courtney-Latimer discover it? Did Dr. Smith?

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Today• In 1997, two American scientists visiting Indonesia

spotted a coelacanth at a fish market. DNA studies have shown it to be a different species of coelacanth, Latimeria menadoensis. Indonesian fisherman had also known about this fish for years, calling it “Raja Laut”—King of the Sea.

• Small populations of coelacanths have been found off the east coast of Africa and one off the coast of Indonesia. Global numbers of both species combined are estimated at about 1,000 individuals. Latimera chalumnae is listed as critically endangered by the International Union for Conservation of Nature and Natural Resources.

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Latimeria menadoensis

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Marjorie Courtenay-Latimer died on May 17, 2004, aged 97

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Slide CreditsSlide 1, Slide 17

Description: Pencil sketch of coelacanthSource: South African Institute for Aquatic Biodiversity (SAIAB).Author: Marjorie Courtenay-LatimerLicensing: Used with permission, which must be sought directly from SAIAB, http://www.saiab.ac.za/.

Slide 2Description: Photo of a youthful Marjorie Courtenay-Latimer.Source: East London MuseumLicensing: Used with permission of East London Museum.

Slide 4, Slide 5, and Slide 14—TopDescription: Illustration of Latimeria chalumnaeSource: FishBase, http://www.fishbase.org/Photos/PicturesSummary.php?

StartRow=4&ID=2063&what=species&TotRec=6Author: Robbie CadaLicensing: Creative Commons Attribution 3.0 Unported License

Slide 12, Slide 14—BottomDescription: Photo of estuary codSource: http://www.reefpix.com.au/petedog.jpgAuthor: Peter HeatherwickLicensing: Used with permission of the author.

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Slide 13, Slide 34Description: Photo of Indonesian coelecanthsSource: South African Institute for Aquatic Biodiversity (SAIAB).Author: JAGO team, SAIAB Catalog Number : 78774 Person : German JAGO Team Date : 22/06/2006Licensing: Used with permission, which must be sought directly from SAIAB, http://www.saiab.ac.za/.

Slide 16Description: Photo of Dr. J.L.B. SmithSource: South African Institute for Aquatic Biodiversity (SAIAB).Licensing: Used with permission, which must be sought directly from SAIAB, http://www.saiab.ac.za/.

Slide 19Description: Fossil of Undinapiscis penicillata, an extinct coelacanthSource: Wikimedia Commons, http://commons.wikimedia.org/wiki/File:Undinapiscis_penicillata.JPGAuthor: GhedoghedoLicensing: Creative Commons Attribution ShareAlike 3.0 License.

Slide 20Description: Photo of Dr. J.L.B. Smith and crew with coelacanth.Source: South African Institute for Aquatic Biodiversity (SAIAB).Licensing: Used with permission, which must be sought directly from SAIAB, http://www.saiab.ac.za/.

Slide 24, Slide 26Description: Phylogenetic treeSource: Based on Atlas of Life on Earth by Douglas Dixon, Ian Jenkins, Richard T. J. Moody & Andrey Yu.

Zhuravlev (Barnes & Noble, 2001, p. 368).Author: Jim Stamos, Department of Biological Sciences, University at Buffalo, 2005.Licensing: Used with permission.

Slide 30Description: Preserved specimen of coelacanth in the Natural History Museum, Vienna, Austria.Source: Wikimedia Commons,

http://commons.wikimedia.org/wiki/File:Latimeria_Chalumnae_-_Coelacanth_-_NHMW.jpgAuthor: Alberto Fernandez FernandezLicensing: Creative Commons Attribution ShareAlike 3.0 License.

Slide 32, Slide 38Description: Marjorie and the coelacanthSource: East London MuseumLicensing: Used with permission of the East London Museum

Slide 37Description: Photo of coelacanth with diver.Author: Mark V Erdmann, Conservation International Indonesian Marine Program.Licensing: Used with permission.