Miguasha fauna is among the most representative of the Devonian Period. It is as if Miguasha is a window with an excellent view onto the world of vertebrates as they branched out during the “Age of Fishes”. Invertebrate animals in aquatic and terrestrial environments were also well represented as they underwent a similar diversification. It was a turning point for many animals in the history of evolution... a time when a number of them began to leave their watery realm and conquer land.

Miguasha fauna includes about twenty essentially endemic fish species, meaning that they are not found in other regions of the globe. These species represented some of the key stages in vertebrate evolution, and they belonged to various groups, many of which are now extinct. Their forms included the most primitive and the most specialized fish in evolutionary history.

Countless animals commingled in the estuarian waters. From large carnivores with strong bodies and sharp teeth, to small bottom-feeding fish eking out their existence by filtering mud, to little spiny fish darting around the water in schools... this ecosystem held as many predators as it did prey! Read More
Miguasha fauna is among the most representative of the Devonian Period. It is as if Miguasha is a window with an excellent view onto the world of vertebrates as they branched out during the “Age of Fishes”. Invertebrate animals in aquatic and terrestrial environments were also well represented as they underwent a similar diversification. It was a turning point for many animals in the history of evolution... a time when a number of them began to leave their watery realm and conquer land.

Miguasha fauna includes about twenty essentially endemic fish species, meaning that they are not found in other regions of the globe. These species represented some of the key stages in vertebrate evolution, and they belonged to various groups, many of which are now extinct. Their forms included the most primitive and the most specialized fish in evolutionary history.

Countless animals commingled in the estuarian waters. From large carnivores with strong bodies and sharp teeth, to small bottom-feeding fish eking out their existence by filtering mud, to little spiny fish darting around the water in schools... this ecosystem held as many predators as it did prey!

At the base of the newly-formed Appalachians, this large estuary served as a link between the mountain rivers and the distant sea. The water was rather oxygen-poor, so lungs became the norm among many fish species. The oxygen that could not be obtained through gills could be drawn in with a few gulps of air. Some Miguasha species may also have adapted to survive out of the water for short periods of time, and even to crawl on the shore with the help of their strong fins before returning to the water.

As a community, Miguasha’s vertebrates and invertebrates, both aquatic and terrestrial, were an integral part of a long-vanished ecosystem that left behind enough detailed traces for us to reconstruct it with considerable accuracy.

© Miguasha National Park 2007

The Miguasha paleoestuary

A fresco of the ancient Miguasha estuary with the peaks of the young Appalachian mountain range in the background. The fish fauna were diversified, but it was Eusthenopteron foordi that dominated this watery world. Vegetation was concentrated along the shore, dense and tall enough in places to make forests.

Miguasha National Park
2003
© Miguasha National Park


Time machines only exist in science fiction. Luckily, paleontologists have other useful tools at their disposal to explore the past.These tools are fossil sites, virtual windows in time through which we may peer at ecosystems that vanished a long time ago.

Some windows are small and grimy. For a number of reasons, such as inadequate preservation, scarcity of specimens, fossil fragmentation or poor representation of species, they offer only a limited view of ancient ecosystems. Other windows are a little bigger and clearer, affording a better view. In extremely rare cases, the windows are very large and offer excellent clarity.

These rare fossil sites displaying exceptional preservation bear the name Lagerstätte, a German word meaning “place of deposition”. The Escuminac Formation includes several layers worthy of the title Lagerstätte due to the abundance of specimens and high quality of preservation, and also the immense insight they have provided into pivotal stages in the evolution of life and the Devonian world in general.

For these reasons, the Miguasha site is celebrated as an extraordinary window in time, opened wide to reveal li Read More
Time machines only exist in science fiction. Luckily, paleontologists have other useful tools at their disposal to explore the past.These tools are fossil sites, virtual windows in time through which we may peer at ecosystems that vanished a long time ago.

Some windows are small and grimy. For a number of reasons, such as inadequate preservation, scarcity of specimens, fossil fragmentation or poor representation of species, they offer only a limited view of ancient ecosystems. Other windows are a little bigger and clearer, affording a better view. In extremely rare cases, the windows are very large and offer excellent clarity.

These rare fossil sites displaying exceptional preservation bear the name Lagerstätte, a German word meaning “place of deposition”. The Escuminac Formation includes several layers worthy of the title Lagerstätte due to the abundance of specimens and high quality of preservation, and also the immense insight they have provided into pivotal stages in the evolution of life and the Devonian world in general.

For these reasons, the Miguasha site is celebrated as an extraordinary window in time, opened wide to reveal life as it was during the Upper Devonian.

© Miguasha National Park 2007

<i>Eusthenopteron foordi</i>

It was during the Devonian Period that sarcopterygian fish gave rise to the first terrestrial vertebrates. Eusthenopteron foordi(shown here) was long thought to be the transitional animal between fish and tetrapods, sharing features with both, but recent discoveries have shown that the elpistostegalians are even more closely related to four-legged vertebrates.

Jean-Pierre Sylvestre
2003
© Miguasha National Park


The Devonian Period set the scene for many events that had a profound impact on the evolutionary history of life on Earth. The animal and plant fossils of Miguasha date back 380 million years to the first half of the Frasnian Age (a division of the Upper Devonian), and represent many of the pivotal moments in the evolution of life. It was during the Devonian that...
The first forests formed, as witnessed by the numerous remains of Archaeopteris, the first known tree; The first seed plant appeared, and the megaspore Spermasporites provides an insight on their origin.; scorpions and myriapods were fossilized at Miguasha, providing valuable information about land-based invertebrate communities; anaspid and ostracoderm fish groups, both agnathans, became extinct, and their last representatives lived and died at Miguasha; placoderms (armoured fish) prospered, only to become extinct shortly after. One of them, Bothriolepis, is found at sites all over th Read More
The Devonian Period set the scene for many events that had a profound impact on the evolutionary history of life on Earth. The animal and plant fossils of Miguasha date back 380 million years to the first half of the Frasnian Age (a division of the Upper Devonian), and represent many of the pivotal moments in the evolution of life. It was during the Devonian that...
  • The first forests formed, as witnessed by the numerous remains of Archaeopteris, the first known tree;
  • The first seed plant appeared, and the megaspore Spermasporites
  • provides an insight on their origin.;
  • scorpions and myriapods were fossilized at Miguasha, providing valuable information about land-based invertebrate communities;
  • anaspid and ostracoderm fish groups, both agnathans, became extinct, and their last representatives lived and died at Miguasha;
  • placoderms (armoured fish) prospered, only to become extinct shortly after. One of them, Bothriolepis, is found at sites all over the world, but it is the Miguasha species, B. canadensis, that is the best described and serves as a reference for other species; the other placoderm, Plourdosteus, was like a smaller version of Dunkleosteus, the giant of the sea at the time;
  • actinopterygians, the ray-finned fish that are so abundant today, began to really diversify. The species at Miguasha, Cheirolepis canadensis, serves as the primitive ancestral model for the group;
  • the sarcopterygians at Miguasha attained a diversity unequalled elsewhere in the world, and some representatives, such as Eusthenopteron foordi, were at the root of lineages that eventually led to the first tetrapods;
  • coelacanths made their first appearance; their most primitive representative is Miguashaia bureaui;
  • dipnoan fish first appeared. Scaumenacia curta is one of the best known fossilized dipnoans;
  • porolepiform fish appeared and then quickly disappeared. Two genera are present at Miguasha. One of them, Holoptychius, was particularly widespread and can also be found in Russia, Scotland, Belgium, New Brunswick, Pennsylvania, etc.
  • elpistostegalian fish made a furtive appearance and then became extinct, but only after giving rise to the first tetrapods. At the heart of this exclusive group are Elpistostege from Miguasha, Panderichthys from Greenland, and Tiktaalik from Canada’s Far North.

© Miguasha National Park 2007

The exceptional preservation of its fossils is the main reason the title of Lagerstätte has been bestowed upon the Escuminac Formation has been bestowed with the title of Lagerstätte. Beautifully preserved fossils. Many examples of high-quality preservation, due to rapid burial and low oxygen levels in the sediments surrounding the remains, were discovered in the past and continue to be on a regular basis, have yielded many fantastic discoveries that continue to this day.

Three-dimensional fossil specimens, just as wide now as they were when alive, provide a very accurate idea of what many of the fishes looked like. The insides of intact Eusthenopteron skulls were studied by X-rays, for example, and specimens of the placoderm genus Bothriolepis were used to correct earlier scientific and artistic reconstructions, adding height to the overly flattened representations. Other excellent examples include specimens of Scaumenacia in which the delicate fins appear “suspended” in sediment, providing valua Read More
The exceptional preservation of its fossils is the main reason the title of Lagerstätte has been bestowed upon the Escuminac Formation has been bestowed with the title of Lagerstätte. Beautifully preserved fossils. Many examples of high-quality preservation, due to rapid burial and low oxygen levels in the sediments surrounding the remains, were discovered in the past and continue to be on a regular basis, have yielded many fantastic discoveries that continue to this day.

Three-dimensional fossil specimens, just as wide now as they were when alive, provide a very accurate idea of what many of the fishes looked like. The insides of intact Eusthenopteron skulls were studied by X-rays, for example, and specimens of the placoderm genus Bothriolepis were used to correct earlier scientific and artistic reconstructions, adding height to the overly flattened representations. Other excellent examples include specimens of Scaumenacia in which the delicate fins appear “suspended” in sediment, providing valuable information about their flexibility.

Fish made of hundreds of small pieces were fossilized without falling apart, a very rare phenomenon indeed. The osteostracan Escuminaspis, for example, had a body covered in a mosaic of thousands of small bony plates, all of which remain in their original positions on in a 40-cm long fossilized specimen. In general, specimens of most fish species at Miguasha, even those that tend to quickly break apart, are found complete.

  • Fossils of juvenile fish allow the skeletal growth and ossification of many species to be established.
  • Preserved traces of soft tissue are numerous. For example, there are many Bothriolepis specimens with their non-bony portions clearly etched into the rock, as if still in motion. Other samples reveal display of blood vessels and aspects features of their internal anatomy. Specimens of boneless fish, such Euphanerops and Endeiolepis, show traces of the gill system, blood vessels, the digestive track, fins, etc.
  • The contents of fossilized excrement, known as coprolites, fossilized excrement, can also be analyzed in detail.
  • Plant leaves are still slightly curved and allow us to observe their fine nervures. Fertile parts are even preserved with clusters of sporangium intact.

© Miguasha National Park 2007

Blood vessels

These blood vessels left their mark on the ventral internal surface of the thorax in a specimen of Bothriolepis canadensis, a placoderm fish. The blood vessels converge toward a dark central zone that represents the heart region.

Miguasha National Park
2003
© Miguasha National Park


<i>Plourdosteus canadensis</i>

This jaw plate from Plourdosteus canadensis was removed from the encasing rock using acid.

Miguasha National Park
2002
© Miguasha National Park


The fossils of the Escuminac Formation are both abundant and exceptionally well preserved. There are so many fossils in the rock layers that even simple erosion of the cliff by rain or springtime that causes them to fall onto the beach below like ripened fruit from a tree.

More than 17,000 vertebrate, invertebrate and plant specimens have been extracted from the cliff since the first official digs in the summer of 1879. About 10,000 of these specimens can be found in the collection of the Natural History Museum at the Parc national de Miguasha. The rest are scattered throughout thirty or so research centers, museums and universities across Canada and throughout the world.

In terms of numbers, the placoderm Bothriolepis canadensis is the best represented, accounting for 28% of the 10,000 specimens in the museum, making a veritable Bothriolepis sanctuary! Even Eusthenopteron, a very rare fish, is well represented, with 1,600 specimens as of 2006. And some of the rock layers are exceptionally fossil-rich, even by Miguasha standards, with up Read More
The fossils of the Escuminac Formation are both abundant and exceptionally well preserved. There are so many fossils in the rock layers that even simple erosion of the cliff by rain or springtime that causes them to fall onto the beach below like ripened fruit from a tree.

More than 17,000 vertebrate, invertebrate and plant specimens have been extracted from the cliff since the first official digs in the summer of 1879. About 10,000 of these specimens can be found in the collection of the Natural History Museum at the Parc national de Miguasha. The rest are scattered throughout thirty or so research centers, museums and universities across Canada and throughout the world.

In terms of numbers, the placoderm Bothriolepis canadensis is the best represented, accounting for 28% of the 10,000 specimens in the museum, making a veritable Bothriolepis sanctuary! Even Eusthenopteron, a very rare fish, is well represented, with 1,600 specimens as of 2006. And some of the rock layers are exceptionally fossil-rich, even by Miguasha standards, with up to 600 specimens of the small acanthodian Triazeugacanthus affinis per square meter!

The sheer abundance of fossils at Miguasha is obviously extraordinary. In fact, a site like this can be considered a “quasi-renewable” fossil resource in the sense that only a small fraction of the rock formation has been excavated and new outcrops have been discovered inland in recent years. What treasures do future excavations have in store for us?

© Miguasha National Park 2007

Rock layers containing many Bothriolepis specimens

The rock layers in the Miguasha cliff contain scores of fossils. This particular example, discovered by the American paleontologist William Patten, reveals a population of the placoderm Bothriolepis.

William Patten
The image is taken from Patten’s 1912 book “The Evolution of the Vertebrates and their Kin” (Figure 257).
1912
© Patten, 1912


A bed of Scaumenacia

Part of a sandstone bed containing numerous specimens of the dipnoan fish Scaumenacia curta.

Miguasha National Park
2002
© Miguasha National Park


Learning Objectives

The learner will:
  • identify and classify different types of fossils;
  • explain the stages of fossilization and the best conditions to create and preserve fossils;
  • make assumptions about the evolution of living beings;
  • make assumptions as to the explanation of the disappearance of some species.

Teachers' Centre Home Page | Find Learning Resources & Lesson Plans