Coelacanth
VIMS Fish Collection
Catalog Number: 8117
Length: 1.452 meters (4.76 feet)
Mass: 53.75 kilograms (118 lbs.)
Accession Date: 1986
The coelacanth, Latimeria chalumnae, is one of the world's best-known "living fossils." These primitive fishes, known from fossils dating back to the Triassic period (240 million years ago), were thought to have become extinct in the Cretaceous (65 million years ago) until a live coelacanth was caught by a commercial trawler that landed in East London, South Africa, in 1938. The specimen was recognized as unusual and preserved by Dr. Marjorie Courtenay Latimer, a local naturalist, teacher, and curator of the East London Natural History Museum. It was described as new to science and named in honor of Latimer by Dr. J. L. B. Smith.
The VIMS coelacanth was collected from the west coast of Grand Comoro Island by the Explorers Club and the New York Aquarium in 1986. It arrived at VIMS in 1987 and was the focus of a "dissection party," which formed the source for much new anatomical and evolutionary data pertaining to coelacanths*.
* J. A. Musick, M. N. Bruton, E. K. Balon (eds.). 1991. The Biology of Latimeria chalumnae and Evolution of Coelacanths (Developments in Environmental Biology of Fishes).
Characteristics
One of the most distinguishing characteristics of the coelacanth is its lobed fins, which resemble the legs of early four-legged land animals. The fish has a three-lobed tail fin, unlike the forked tail fin of most modern fishes. The coelacanth has a hollow, fluid-filled backbone, calcifiecd scales, true enamel teeth, and a hinged skull allowing for wide opening of the mouth. The color is a deep metallic blue (sometimes almost brown) with irregular white spots. The maximum size of adults is slightly more than 1.8 meters (6 feet) in length. Female coelacanths carry between 20 and 65 developing eggs; the eggs are large (3 1/2 inches in diameter) and hatch internally.
Habitat
Coelacanths live in deep-water communities at depths of around 180-200 meters (600-650 feet) and salinities of 35 ppt. The temperature at this depth averages around 18-20°C (~68°F), which is the optimal temperature for oxygen to be absorbed by the coelacanth's blood. The white markings on the coelocanth may serve as camouflage in its cave habitat where surroundings are covered with white sponges and white oyster shells.
Feeding/Diet
The coelacanth is a piscivorous (fish-eating), nocturnal animal. It resides in caves during daylight hours, possibly for protection from predatory sharks and to save energy for night feeding. Hans Fricke, the first scientist to observe the coelacanth in its natural habitat, characterized the fish as a "drift hunter," a creature that drifts over the bottom snapping at prey when encountered.
Movement
The movement of the coelacanth is unique. It was once thought the animal "walked" along the ocean floor with its lobed fins. However, this hypothesis was disproved by Hans Fricke, who observed the fish swimming through the water column and moving its fins in an alternating pattern similar to that of a four-legged animal.
Conservation
As the only living representative of a group that was once widespread and diverse, the coelacanth has provided vast amounts of information to scientists everywhere. The last surviving coelacanths have slow growth, low birth rates, and limited habitat; conservation is thus of great importance to survival of the species.
Range
One population is known to exist off Grand Comoro and Anjouan Islands along the eastern coast of Africa; another population was discovered in 1998 near Indonesia. This population is morphologically and genetically distinct from the African coelacanths, and was named a second species, Latimeria menadoensis, in 1999. The two sites lie more than 10,000 kilometers apart.