Coelacanths ( adaptation of Modern Latin Cœlacanthus "hollow spine", from Greek κοῖλ-ος koilos "hollow" + ἄκανθ-α akantha "spine", referring to the hollow caudal fin rays of the first fossil specimen described and named by Louis Agassiz in 1839  are members of an order of fish that includes the oldest known living lineage of Sarcopterygii (lobe-finned fish and tetrapods).

 

Coelacanths belong to the subclass Actinistia, a group of lobed-finned fish that are related to lungfish and certain extinct Devonian fish such as osteolepiforms, porolepiforms, rhizodonts, and Panderichthys. Coelacanths were thought to have gone extinct in the Late Cretaceous, but were rediscovered in 1938 off the coast of South Africa.

 

Latimeria chalumnae and the Latimeria menadoensis are the only two living coelacanth species, which are found along the coastlines of the Indian Ocean and Indonesia. The coelacanth is considered a “living fossil” due to its apparent lack of significant evolution over the past millions of years.The coelacanth is thought to have evolved into roughly its current form approximately 400 million years ago.

 


Latimeria chalumnae

 Illustration by Ken McKeighen


West Indian Ocean coelacanth (Latimeria chalumnae) is a species of coelacanth, known for its vivid blue pigment. It is the better known of the two extant species. 


Listen to internet radio with Under The Sea Radio Show on Blog Talk Radio

On Friday October 19th at 10 PM EST, 9 PM CST, 7 PM PST.

 

Perhaps when some people look back to think about prehistoric life a fear may arise from them and many themes of movies are based around prehistoric creatures. On our planet there are some prehistoric type animals alive today such as sharks, snakes and many types of animals that these themes are based around.

 

However once called the missing fossil the Coelacanth still swims in our oceans today. What was their world like from the time when many of the Coelacanth species were abundant in our oceans.

 

 Mr Ken McKeighen will be on the show to discuss some interesting facts about the Coelacanths today and we will look back in time for what may have been a very interesting habitat on our planet when the  Coelacanths roamed the water ways here on our planet.

 

For more information about this episode click the following link.

 

http://underthesearadioprogram.yolasite.com/monster-fish-coelacanths.php

 

Feel Free to visit the Under The Sea Radio Show website for other information about this episode and more

 

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Discovery: 

The coelacanths, which are related to lungfishes and tetrapods, were believed to have been extinct since the end of the Cretaceous period. More closely related to tetrapods than even the ray-finned fish, coelacanths were considered to be transitional species between fish and tetrapods until the first Latimeria specimen was found off the east coast of South Africa, off the Chalumna River (now Tyolomnqa) in 1938. Museum curator Marjorie Courtenay-Latimer discovered the fish among the catch of a local angler, Captain Hendrick Goosen, on December 23, 1938. A local chemistry professor, JLB Smith, confirmed the fish's importance with a famous cable: "MOST IMPORTANT PRESERVE SKELETON AND GILLS = FISH DESCRIBED".

 

The discovery of a species still living, when they were believed to have gone extinct 65 million years previously, makes the coelacanth the best-known example of a Lazarus taxon, a species that seems to have disappeared from the fossil record only to reappear much later. Since 1938, Latimeria chalumnae have been found in the Comoros, Kenya, Tanzania, Mozambique, Madagascar, and in iSimangaliso Wetland Park, Kwazulu-Natal in South Africa.

 

The second extant species, L. menadoensis, was described from Manado, North Sulawesi, Indonesia in 1999 by Pouyaud et al. based on a specimen discovered by Erdmann in 1998[8] and deposited at the Indonesian Institute of Sciences (LIPI). Only a photograph of the first specimen of this species was made at a local market by Arnaz and Mark Erdmann before it was bought by a shopper.

 

The coelacanth has no real commercial value, apart from being coveted by museums and private collectors. As a food fish the coelacanth is almost worthless, as its tissues exude oils that give the flesh a foul flavour. The continued survivability of the coelacanth may be threatened by commercial deep-sea trawling.

 

Physical Description: 

Coelacanths are a part of the clade Sarcopterygii, or the lobe-finned fishes. Externally, there are several characteristics that distinguish the coelacanth from other lobe-finned fish. They possess a three-lobed caudal fin, also called a trilobate fin. A secondary tail that goes along and extends past the primary tail separates the upper and lower halves of the coelacanth. Cosmoid scales act as thick armor that protects the exterior of the coelacanth. There also are several internal traits that aid in differentiating coelacanths from other lobe-finned fish. At the back of the skull, the coelacanth possesses a hinge, the intracranial joint, which allows it to open its mouth extremely widely. Coelacanths also retain a notochord, a hollow, pressurized tube which is replaced by the vertebral column early in embryonic development in most other vertebrates. The heart of the coelacanth is shaped differently than most modern fish; the heart's chambers are arranged in a straight tube. The coelacanth braincase is 98.5% filled with fat; only 1.5% of the braincase contains brain tissue. The cheeks of the coelacanths are unique because the opercular bone is very small and holds a large soft-tissue opercular flap. The coelacanth also contains a unique rostral organ within the ethmoid region of the braincase. Also unique to extant coelacanth, is the presence of a "fatty lung" or a fat-filled single-lobed vestigial lung. 

The Indonesian Coelacanth (Latimeria menadoensis) (Indonesian: raja laut) is one of two living species of coelacanth, identifiable by its brown color.

 

On September 18, 1997, Arnaz and Mark Erdmann, traveling in Indonesia on their honeymoon, saw a strange fish enter the market at Manado Tua, on the island of Sulawesi. Mark thought it was a gombessa (Comoro coelacanth), although it was brown, not blue. An expert noticed their pictures on the Internet and realized its significance. Subsequently, the Erdmanns contacted local fishermen and asked for any future catches of the fish to be brought to them. A second Indonesian specimen, 1.2 m in length and weighing 29 kg., was captured alive on July 30, 1998. It lived for six hours, allowing scientists to photographically document its coloration, fin movements and general behavior. The specimen was preserved and donated to the Museum Zoologicum Bogoriense (MZB), part of the Indonesian Institute of Sciences (LIPI).

 

DNA testing revealed that this specimen differed genetically from the Comorian population.Superficially, the Indonesian coelacanth, locally called raja laut ("King of the Sea"), appears to be the same as those found in the Comoros except that the background coloration of the skin is brownish-gray rather than bluish. This fish was described in a 1999 issue of Comptes Rendus de l'Académie des sciences Paris by Pouyaud et al. It was given the scientific name Latimeria menadoensis.In 2005, a molecular study estimated the divergence time between the two coelacanth species to be 40–30 mya.


 


Undina penicillata 

 

Undina is a genus of prehistoric coelacanth, lobe-finned fish, an intermediary form between sea and land animals which lived during the Late Jurassic period.

General Description:

Latimeria chalumnae and L. menadoensis are the only two known living coelacanth species. The word coelacanth literally means, “hollow spine,” because of its unique hollow spine fins. Coelacanths are large, plump, lobe-finned fish that grow up to 1.8 meters. They are nocturnal piscivorous drift-hunters. The body is covered in cosmoid scales that act as armor. Coelacanths have 8 fins – 2 dorsal fins, 2 pectoral fins, 2 pelvic fins, 1 anal fin, and 1 caudal fin. The tail is very nearly equally proportioned and is split by a terminal tuft of fin rays that make up the caudal lobe of the tail. The eyes of the coelacanth are very large, while the mouth is very small. The eye is acclimatized to seeing in poor light by having rods that absorb mostly low wavelengths. The vision of Coelacanths has evolved to a mainly blue-shifted color capacity.

 

Pseudomaxillary folds surround the mouth, which replace the maxilla, a structure that is absent in coelacanths. There are two nostrils along with four other external openings that appear between the premaxilla and lateral rostral bones. The nasal sacs resemble those of many other fish and do not contain an internal nostril. The rostral organ of the coelacanth is contained within the ethmoid region of the braincase. It has three unguarded openings into the environment. The rostral organ is used as a part of the coelacanths’ laterosensory system. The coelacanths’ auditory reception is mediated by its inner ear. The inner ear of the coelacanth is very similar to that of tetrapods because it is classified as being a basilar papilla.

 


Scientific Classification:




Latimeria chalumnae embryo with its yolk sac from the Muséum national d'histoire naturelle. 

 

The average weight of the living West Indian Ocean coelacanth, Latimeria chalumnae, is 80 kg (176 lb), and they can reach up to 2 m (6.5 ft) in length. Adult females are slightly larger than males. L. chalumnae is widely but very sparsely distributed around the rim of the western Indian Ocean, from South Africa northward along the east African coast to Kenya, the Comoros and Madagascar, seemingly occurring in small colonies.

 

In accordance with the Convention on International Trade of Endangered Species treaty, the coelacanth was added to Appendix I (threatened with extinction) in 1989. The treaty forbids international trade for commercial purposes and regulates all trade, including sending specimens to museums, through a system of permits. In 1998, the total population of the West Indian Ocean coelacanth was estimated to have been 500 or fewer, a number that would threaten the survival of the species.
L. chalumniae is listed as critically endangered and L. menadoensis is listed as vulnerable by IUCN.

 


The following is a classification of known coelacanth genera and families: 

Whiteiidae is an extinct family of prehistoric coelacanth fishes which lived during the Triassic period.

 

 

Piveteauia is an extinct genus of prehistoric coelacanth fish which lived during the Lower Triassic period. The genus is named for twentieth century French vertebrate paleontologist Jean Piveteau. The type specimen was discovered in the Middle Sakamena Group in northwestern Madagascar  by French paleoichthyologist Jean-Pierre Lehman 

Piveteauia madagascariensis 


Genus: 

 

Whiteia is an extinct genus of prehistoric coelacanth fish which lived during the Triassic period.

 

 Whiteia woodwardi in Muséum de Toulouse


Rebellatrix ("rebel coelacanth", after the unique tail fin) is a genus of large prehistoric coelacanth from the Lower Triassic Sulphur Mountain formation and Wapiti Lake Provincial Park of British Columbia. It is known from a single species, R. divaricerca ("forked tail"), which is the only known species of the family Rebellatricidae. Its most distinguishing feature was its tuna-like forked tail (unusual for an actinistian fish), which suggested a fast-swimming and active lifestyle, unlike coelacanths related to the living species.


The holotype specimen is a nearly complete fossil, with the exception of some fins and a large amount of the skull, as well as an incomplete tail fin. Three other specimens reveal the rest of the tail. The rebel coelacanth may have reached 1.30 metres (4 ft 3 in) in length. In addition to its uniquely forked (and symmetrical) tail fin, the posterior dorsal fin is behind the anal fin rather than opposite it. Rebellatrix is believed to have been a fast-swimming predator, since its tail is clearly built for speed, and modern coelacanths only use the tail fin when attacking prey, and would have been one of the first non-sharks to fill this niche. 

 

Rebellatrix ("rebel coelacanth", after the unique tail fin) is a genus of large prehistoric coelacanth from the Lower Triassic Sulphur Mountain formation and Wapiti Lake Provincial Park of British Columbia. It is known from a single species, R. divaricerca ("forked tail"), which is the only known species of the family Rebellatricidae. Its most distinguishing feature was its tuna-like forked tail (unusual for an actinistian fish), which suggested a fast-swimming and active lifestyle, unlike coelacanths related to the living species.


The holotype specimen is a nearly complete fossil, with the exception of some fins and a large amount of the skull, as well as an incomplete tail fin. Three other specimens reveal the rest of the tail. The rebel coelacanth may have reached 1.30 metres (4 ft 3 in) in length. In addition to its uniquely forked (and symmetrical) tail fin, the posterior dorsal fin is behind the anal fin rather than opposite it. Rebellatrix is believed to have been a fast-swimming predator, since its tail is clearly built for speed, and modern coelacanths only use the tail fin when attacking prey, and would have been one of the first non-sharks to fill this niche. 

 

Coelacanthidae is an extinct family of coelacanths found throughout the world, originating during the Permian, and finally dying out during the Jurassic.


The modern-day genus Latimeria is often erroneously thought to be in this family, when, in fact, it is in the more advanced family Latimeriidae, which appeared some time during the Triassic. 

Coelacanthus whitea 


Axelia is a prehistoric genus of lobe-finned fish which belonged to the family of Coelacanthidae. 

 

Coelacanthus ("Hollow Spine") is a genus of extinct coelacanths that first appearing during the Permian period. In fact, this was the first genus of coelacanths ever described, as the order Coelacanthiformes is named after it.


They bear a superficial similarity to the living Latimeria, though they were smaller, and had more elongated heads. Individuals grew up to 3 feet in length, and had small lobed fins, suggesting that Coelacanthus were open-water predators.


Coelacanthus was a long-lived genus with a worldwide distribution. They survived the Permian–Triassic extinction event, and eventually died out during the Late Jurassic, around 145 million years ago.  

Coelacanthus granulatus Fossil 


Ticinepomis is an extinct genus of coelacanth lobe-finned fish which lived during the Triassic period. It belonged to the family of Coelacanthidae. 

Ticinepomis peyeri 


Wimania is an extinct genus of coelacanth which lived during the Triassic period. It belonged to the family of Coelacanthidae. 

 


Unknown: 

 

Mawsoniidae is an extinct family of prehistoric coelacanth fishes which lived during the Triassic to Cretaceous period. 

 

Alcoveria is an extinct genus of coelacanth fish which lived during the Triassic period. 

 

Axelrodichthys is an extinct genus of mawsoniid coelacanth from the Early Cretaceous of South America. 

Axelrodichthys araripensis 


 Genus: 

Chinlea is an extinct genus of Triassic lobe-finned fish found in the Southwestern United States states of Arizona and New Mexico. The length of Chinlea was about 1.5 m (5 feet). It weighed around 68 kg. (150 pounds). Chinlea had lobed fins and a slender tail. The teeth were large and sharp. 

Chinlea species 


Chinlea species. Coelacanth 

Painted By Ken McKeighen


 Genus: 

Diplurus is a genus of prehistoric coelacanth fish which lived during the Triassic period.

 

 

Mawsonia is an extinct genus of prehistoric coelacanth fish, and the largest of this group, up to several metres long.

 

It lived during the Cretaceous period (Albian stage, about 99 to 112 million years ago). Fossils have been found in Africa and South America. Mawsonia was first described by British palaeontologist Arthur Smith Woodward in 1907.

 

Mawsonia branchial plates 


 

According to genetic analysis of current species, the divergence of coelacanths, lungfish, and tetrapods is thought to have occurred 390 million years ago. Coelacanths were thought to have undergone extinction 65 million years ago during the Cretaceous–Paleogene extinction event. The first recorded coelacanth fossil was found in Australia and was of a coelacanth jaw that dated back 360 million years, named Eoachtinistia foreyi. The most recent species of coelacanth in the fossil record is the Macropoma. Macropoma, a sister species to Latimeria chalumnae, is separated by 80 million years. The fossil record of the coelacanth is unique because coelacanth fossils were found 100 years before the first live specimen was identified. In 1938, Courtenay-Latimer rediscovered the first live specimen, L. chalumnae, which was caught off of the coast of East London, South Africa. In 1997, a marine biologist was on a honeymoon and discovered the second live species, Latimeria menadoensis in an Indonesian market. In July 1998, the first live specimen of Latimeria menadoensis was caught in Indonesia. Approximately 80 species have been described. Before the discovery of a live coelacanth specimen, the coelacanth time range was thought to have spanned from the Middle Devonian to the Upper Cretaceous period. Except for one or two specimens, all fossils found during that time demonstrated a similar morphology. 


Holophagus is an extinct genus of lobe-finned fish. It lived through the Jurassic period.

 

Holophagus acutidens 


Latimeria is a genus comprising the living species of coelacanth.

 

Female coelacanths give birth to live young, called "pups", in groups of between five and 25 fry at a time; the pups are capable of surviving on their own immediately after birth. Their reproductive behaviors are not well known, but it is believed that they are not sexually mature until after 20 years of age. Gestation time is estimated to be 13 to 15 months.

 

Based on growth rings in their ear bones (otoliths), scientists infer that individual coelacanths may live as long as 80 to 100 years. Coelacanths live as deep as 700 m (2300 ft) below sea level, but are more commonly found at depths of 90 to 200 m. Living examples of Latimeria chalumnae have a deep blue color which probably camouflages them from prey species; however, the Indonesian species (L. menadoensis) is brown.

 

Latimeria chalumnae model in the Oxford University Museum of Natural History, showing the coloration in life 


 First Found in South Africa:

 

On December 23, 1938, Hendrik Goosen, the captain of the trawler Nerine, returned to the harbour at East London, South Africa, after a trawl between the Chalumna and Ncera Rivers. As he frequently did, he telephoned his friend, Marjorie Courtenay-Latimer, curator at East London's small museum, to see if she wanted to look over the contents of the catch for anything interesting, and told her of the strange fish he had set aside for her. Correspondence in the archives of the South African Institute for Aquatic Biodiversity (SAIAB, formerly the JLB Smith Institute of Ichthyology) show that Goosen went to great lengths to avoid any damage to this fish and ordered his crew to set it aside for the East London Museum. Goosen later told how the fish was steely blue when first seen but by the time the Nerine entered East London harbour many hours later the fish had become dark grey.

 

Failing to find a description of the creature in any of her books, she attempted to contact her friend, Professor James Leonard Brierley Smith, but he was away for Christmas. Unable to preserve the fish, she reluctantly sent it to a taxidermist. When Smith returned, he immediately recognized it as a coelacanth, known only from fossils. Smith named the fish Latimeria chalumnae in honor of Marjorie Courtenay-Latimer and the waters in which it was found. The two discoverers received immediate recognition, and the fish became known as a "living fossil". The 1938 coelacanth is still on display in the East London, South Africa, museum.

Preserved specimen of Latimeria chalumnae in the Natural History Museum, Vienna, Austria (length: 170 cm - weight: 60 kg). This specimen was caught on 18 October 1974, next to Salimani/Selimani (Grand Comoro, Comoro Islands) 11°48′40.7″S 43°16′3.3″E. 

The Second Specimen:

Malania anjouanae 

A second specimen with a missing dorsal fin and deformed tail fin was captured in 1952 off the coast of Anjouan. At the time it was believed to be a new species and placed in a new genus as well, Malania, named in honour of the Prime Minister of South Africa at the time, Daniel François Malan, without whose help the specimen would not have been preserved with its muscles and internal organs more or less intact.


 On September 18, 1997, Arnaz and Mark Erdmann, traveling in Indonesia on their honeymoon, saw a strange fish enter the market at Manado Tua, on the island of Sulawesi. Mark thought it was a gombessa (Comoro coelacanth), although it was brown, not blue. An expert noticed their pictures on the Internet and realized its significance. Subsequently, the Erdmanns contacted local fishermen and asked for any future catches of the fish to be brought to them. A second Indonesian specimen, 1.2 m in length and weighing 29 kg., was captured alive on July 30, 1998.


It lived for six hours, allowing scientists to photographically document its coloration, fin movements and general behavior. The specimen was preserved and donated to the Museum Zoologicum Bogoriense (MZB), part of the Indonesian Institute of Sciences (LIPI).


DNA testing revealed that this specimen differed genetically from the Comorian population. Superficially, the Indonesian coelacanth, locally called raja laut ("King of the Sea"), appears to be the same as those found in the Comoros except that the background coloration of the skin is brownish-gray rather than bluish. This fish was described in a 1999 issue of Comptes Rendus de l'Académie des sciences Paris by Pouyaud et al. It was given the scientific name Latimeria menadoensis. In 2005, a molecular study estimated the divergence time between the two coelacanth species to be 40–30 mya

Cover: The meeting of two distant relatives, an Indonesian coelacanth (Latimeria menadoensis) and a representative of Homo sapiens. Coelacanths, the famous "living fossils," are one of only two remaining lineages of lobe-finned fishes, the only extant sister group to terrestrial vertebrates. As such, coelacanths occupy a critical and highly informative position between ray-finned fishes, such as zebrafish, and tetrapods (represented by the phylogenetic tree in the background). A comparison of human, coelacanth, and zebrafish protocadherin clusters (colored blocks) indicates that the coelacanth genome is more similar to the genomes of land vertebrates than is any teleost genome. In this issue, it is argued that the sequence of the coelacanth genome is an essential tool for identifying the molecular events that accompanied the evolution of tetrapods from their aquatic ancestors. (Cover illustration by Bang Wong, ClearScience/ www.clearscience.info. Photo: Mark V. Erdmann. [For details, see Noonan el al., pp. 2397–2405.]) 


Libys is a genus of the prehistoric coelacanth lobe-finned fish, an intermediary form between sea and land animals. It belongs to the family of Latimeridae, which is also the family of the living coelacanth, Latimeria. These fishes lived during the Upper Jurassic period (Kimmeridgian - Tithonian, about 150 to 145 million years ago).


 Libys had an exceptionally squat body, especially when compared to other coelacanths of the same period as Undina and Holophagus species. Libys could reach 60 centimeters in length and was therefore a medium-sized coelacanth, with a short and high skull. The pectoral fins were quite long, while the tail was remarkably short and high.


Fossils of these fishes have been found in Germany, in the famous deposits of Solnhofen.


 Genus Libys has been described for the first time in 1842 by Muenster. The species Libys polypterus was then established as the type species, on the basis of fragmentary remains. Later has been described another species (Libys superbus), on the basis of a complete large specimens, but most authors believe that these two forms have in reality to be considered conspecific. 

 Libys superbus at the Naturhistorisches Museum, Wien


 Macropoma (meaning big apple or large fruit) is an extinct Genus of coelacanth in the class Sarcopterygii. These fishes have apparently been extinct for over 70 million years and are most closely related to the modern coelacanth Latimeria.


Fossils of Macropoma have been found in both England and Czechoslovakia. Recorded fossils have bodies under two feet in length. A modern coelacanth measures five or more, but in other respects the two genera are remarkably similar, and share the same body plan with a three-lobed tail and stalked fins.


Macropoma grew to a length of 22 inches (55 centimeters) and would have preyed upon smaller aquatic species.

Life restoration of Macropoma

 Macropomoides is an extinct genus of lobe-finned fish which lived during the Cretaceous period.

 Macropomoides orientalis from Lebanon


 Megacoelacanthus is an extinct genus of lobe-finned fish which lived during the Jurassic period.

 

 Swenzia is an extinct genus of prehistoric coelacanth.

 

Undina is a genus of prehistoric coelacanth, lobe-finned fish, an intermediary form between sea and land animals which lived during the Late Jurassic period. 

Undina acutidens, abt. 25 cm long, at the Naturhistorisches Museum, Wien 


 Timeline of Genera:


Click on Image to see larger image 


Click on Image to See Larger Image 

This map shows where known specimens of extant Coelacanths have been found. 

Geographical Distribution: 

 The current coelacanth range remains primarily around the eastern African coast, although the Latimeria menadoensis was discovered off the coast of Indonesia. Coelacanths have been found in the waters of Kenya, Tanzania, Mozambique, South Africa, Madagascar, Comoros, and Indonesia. Most Latimeria chalumnae specimens that have been caught have been captured around the islands of Grande Comore and Anjouan in the Comoros Archipelago, Indian Ocean. Though there have been cases of L. chalumnae being caught elsewhere, amino acid sequencing has shown there is no big difference between these exceptions and the ones found around Comore and Anjouan. Even though these few may be considered strays, there have been several reports of coelacanths being caught off of the coast of Madagascar. This leads scientists to believe that the endemic range of Latimeria chalumnae coelacanths stretches down the eastern coast of Africa from the Comoros Islands, past the western coast of Madagascar, to the South African coastline. The geographical range of the Indonesia coelacanth, Latimeria menadoensis, is believed to be off the coast of Manado Tua Island, Sulawesi, Indonesia in the Celebes Sea. The key components that keep coelacanths in these areas are food and temperature restrictions.


Ecology: 

During the daytime, coelacanths rest in caves anywhere from 100–500 meters deep while others migrate to deeper waters. By resting in cooler waters (below 120 meters) during the daytime, coelacanths reduce metabolic costs. By drifting toward reefs and feeding at night, they save vital energy. Staying in caves during the day also saves energy because they do not have to waste energy fighting the currents.


Because coelacanths hide in caves during the daytime, the Anjouan island and Grande Comore provide ideal habitats for them. The steeply eroded underwater volcanic slopes covered in sand also house an obscure system of caves and crevices, allowing the coelacanths a place to stay during the daylight hours. These crevices support a large benthic fish population that can sustain coelacanth populations. 


Coelacanths are nocturnal piscivores who feed mainly on benthic fish populations. By floating along the lava cliffs, presumably, they feed on whatever fish they encounter. 


Coelacanths are fairly peaceful creatures when dealing with other coelacanths. They remain calm, even while in a crowded cave. 

 The discovery of a living Coelacanth was in an article in the London Daily Dispatch newpaper on February 20th 1939

 They do avoid body contact, however, withdrawing immediately if contact is made with another coelacanth. When approached by foreign, potential predators (e.g. a submersible), they react with panic flight reactions. Coelacanths are most likely prey to large deep-water predators. Shark bite marks have been seen on coelacanths and sharks are very common in areas inhabited by coelacanths. Electrophoresis testing of 14 coelacanth enzymes has shown that there is little genetic diversity between coelacanth populations. Among the fish that have been caught, there have been about equal numbers of males and females. Population estimates range from 210 individuals per population, all the way to 500 individuals per population. Because coelacanths have individual color markings, scientists think that coelacanths are able to recognize other coelacanths via electric communication.


Latimeria chalumnae

Critically Endangered 

Conservation: 

Because little is known about the coelacanth, the conservation status is difficult to characterize. According to Fricke et al. (1995), there should be some stress put on the importance of conserving this species. From 1988 to 1994, Fricke counted some 60 individuals on each dive. In 1995 that number dropped to 40. Even though this could be a result of natural population fluctuation, it also could be a result of overfishing. Coelacanths usually are caught when local fishermen are fishing for oilfish. Fishermen will sometimes snag a coelacanth instead of an oilfish because they traditionally fish at nighttime when the oilfish (and coelacanths) are feeding. Before scientists became interested in coelacanths, they were thrown back into the water if caught. Now that there is an interest in them, fishermen trade them in to scientists or other officials once they have been caught. Before the 1980s, this was a problem for coelacanth populations. In the 1980s, international aid gave fiberglass boats to the local fishermen and it resulted in fishing out of coelacanth territories into more fish-productive waters. Since then, most of the motors on the boats have broken down so the local fishermen are now back in the coelacanth territory, putting the species at risk. 

 Different methods to minimize the number of coelacanths caught include moving fishers away from the shore, using different laxatives and malarial salves to reduce the quantity of oilfish needed, using coelacanth models to simulate live specimen, and coelacanth protection awareness. In 1987 the Coelacanth Conservation Council was established to help protect and encourage population growth of coelacanths.


In 2002, the South African Coelacanth Conservation and Genome Resource Programme was launched to help further the studies and conservation of the coelacanth. The South African Coelacanth Conservation and Genome Resource Programme focuses on biodiversity conservation, evolutionary biology, capacity building, and public understanding. The South African government committed to spending R10 million on the program.


 Latimeria menadoensis

Vulnerable

 Life History:

Coelacanths are ovoviviparous, meaning that the mother retains the eggs within her body while the embryos develop within them, with a gestation period of more than a year.  Typically, the females are larger than the males and their scales and folds of skin around the

cloaca differ. The male coelacanth does not have distinct copulatory organs, just a cloaca. The cloaca has an urogential papilla that is surrounded by erectile caruncles. It is hypothesized that the cloaca turns itself inside out to serve as a copulatory organ. The eggs of the coelacanth are very large and have only a thin layer of membrane protecting them. The embryos hatch within the mother and eventually the mother gives live birth. Young coelacanths look very similar to adult coelacanths. The main differences include an external yolk sac, larger eyes relative to their body size, and a more pronounced downward slope of the body. The yolk sac of the juvenile coelacanth is broad and comes out from below the pelvic fins. The scales and the fins of the juvenile coelacanth are completely matured. The young coelacanth does lack odontodes, but gains them during maturity.


Human Consumption: 


Coelacanth are considered a poor source of food for humans and likely most other fish-eating animals. Coelacanth flesh has high amounts of oil, urea, wax esters, and other compounds that are difficult to digest and can cause diarrhea. Where the coelacanth is more common, local fishermen avoid it because of its potential to sicken consumers. 


External Links of Interest:


Nova - The Public Broadcasting System has an interesting interactive software display on the Anatomy of the Coelacanth to view this display your computer will require flash. 


Website Editors Note: - "Very informative interactive display that would be a great tool for teaching children about this missing link that is a survivor from the age of the Dinosaurs" Click on the PBS logo to the left to go and see this display.


Dinofish.com is an incredible site for those that are interested in Coelacanths. (The Site requires a frame capable browser to be viewed.) 


Click on the Coelacanth Information graphic to the left to go see this fabulous website.


Spiegel Online Website - has some excellent photographs of Coelacanths in their habitat. However the description of the images are discribed in the German Language. The photography though in these photographs are amazing. A must see for those that would like to see these prehistoric fish in their natural habitat. 



In Search of the Cœlacanthe: 

Director: Sophie Bontemps | Producer: Maurice Ribière

Genre: Documentary | Produced In: 1994

Story Teller's Country: France 

Synopsis: It's steel blue and is the only fish still in existence whose species has not evolved for 350 million years. It's called the "coelacanth". It was thought to have become extinct 70 million years ago. Only fossils remained, which paleontologists studied at the beginning of this century. In fact, the coelacanth resembles the fish which worked their way onto dry earth and from which all vertebrates descend ... including man. From 1952 until now, we follow the remarkable story of the coelacanth and the passion it has unleashed on all continents. 

Review: An amazing documentary about the fish known as a living fossil by those that study paleontology. The website team of the Under The Sea Radio Show wishes to thank the monster fish community of Queensland Cichlid Forum for pointing this documentary out to the attention of that forums users and ranks this film as a great resource for those that like to study prehistoric fish.  


Link: http://www.cultureunplugged.com/documentary/watch-online/play/5857/In-Search-of-the-C--lacanthe/?pp=share