![Geological Survey of Canada Geological Survey of Canada](/web/20061103043517im_/http://www.gsc.nrcan.gc.ca/esst_images/gsc_e.jpeg) Natural Resources Canada > Earth Sciences Sector > Geological Survey of Canada > Past lives: Chronicles of Canadian Paleontology
Past lives: Chronicles of Canadian Paleontology Eusthenopteron - the Prince of Miguasha
Through the efforts of a
Swedish paleontologist over many decades, Eusthenopteron from the Gaspé
is now the best known fossil fish anywhere. Its interior skeleton clearly
anticipates that of a terrestrial tetrapod, but in scale, fin and tail, it is
undeniably a fish
![Le Prince de Miguasha - a 30 cm long specimen of Eusthenopteron from the Upper Devonian cliffs at Miguasha. Miguasha Museum Collections. This specimen is also featured on a Canada Post stamp. (Photo by BDEC (c).) Le Prince de Miguasha - a 30 cm long specimen of Eusthenopteron from the Upper Devonian cliffs at Miguasha. Miguasha Museum Collections. This specimen is also featured on a Canada Post stamp. (Photo by BDEC (c).)](/web/20061103043517im_/http://www.gsc.nrcan.gc.ca/paleochron/images/eustheno.jpg) Le Prince de Miguasha - a 30 cm long specimen of Eusthenopteron from the Upper Devonian cliffs at Miguasha. Miguasha Museum Collections. This specimen is also featured on a Canada Post stamp.
(Photo by BDEC (c).) |
In 1925 Joseph Landry, a farmer
at Miguasha, Gaspé Peninsula, shipped a large crate to the
Swedish Museum of Natural History. Packed inside was a superb
half-metre long specimen of Eusthenopteron -- virtually
complete and preserved in three-dimensions -- a fish that died
380 million years ago, but in appearance not much different from
one lying on a fishmonger's slab. Landry, who collected fish
fossils for the museum on commission, was paid $50 for this
specimen.
At the museum in Stockholm, the
paleoichthyologist Erik Jarvik began a detailed analysis of this
specimen of Eusthenopteron. First he serial sectioned the
head; that is, grinding it down a fraction of a millimetre at a
time, and mapping the detailed distribution of bone and matrix.
Thus, he was able to determine the conduit of nerves and blood
vessels and the position and shape of glands, organs, and the
braincase. Later, he prepared through the scales to expose the
vertebral column and the bones supporting the fins. This
meticulous work, which was accomplished over decades, was
justified by the position this lobe-finned fish occupies in the
evolution of land-dwelling tetrapods.
The lobe-finned fishes comprise
three groups -- lungfishes, coelacanths and rhipidistians. All
of these groups began in the Devonian. The lungfishes are
represented today by three genera, the coelacanths by a single
genus. The rhipidistians, which includes Eusthenopteron,
did not survive the Paleozoic, but this group includes the
ancestors of all tetrapods.
Jarvik's work on
Landry's specimen of Eusthenopteron was communicated
in a remarkable series of papers published from the 1940s through
to the '90s. He showed that the skull matches closely those
of early amphibians and that the teeth are characterized by
complex infolding of the dentine called labyrinthodont, also
present in primitive tetrapods. His preparation of the paired
belly fins showed that the front fin was supported by bones
identifiable as a humerus, ulna and radius, and the rear fins by
a femur, fibula and tibia. Clearly, the fins of Eusthenopteron
contained the bones of the paired limbs of all tetrapods,
although bones distal to a wrist or ankle are not present.
More than 2000 specimens of Eusthenopteron
have been collected from the Upper Devonian rocks exposed at the
Miguasha cliffs. This striking fossil is the pride of Le Musée
d'Histoire Naturelle de Miguasha and has been dubbed, le
Prince de Miguasha.
Further reading:
Schultze, H.-P. and Cloutier, R. (editors) |
1996: |
Devonian fishes and plants of Miguasha, Quebec, Canada. Verlag Dr. Friedrich Pfeil, Munich, 374 p. |
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