Virtual Museum of Canada

Miguasha : From water to land (The Miguasha National Park)

The Devonian: Age of Fishes

Welcome to Upper Devonian time. During our visit to the Earth of 380 million years ago, we must forget all that is familiar to us and put ourselves in the place of a space traveler who is arriving at a new planet for the first time...Miguasha during Devonian timemagnifying(124 kb) The change of scenery is that dramatic!

Could this really be the Earth, this planet with unrecognizable continents and a northern hemisphere covered by an unending ocean? The six continents and two large oceans we know so well do not even exist yet. And the climate seems hotter than usual; in fact, there is no ice at the North Pole! Not only that, but the days aren’t even the same length!

Evolutionary tree showing the main vertebrate groupsmagnifying(60 kb)A glance at Upper Devonian animals and plants is just as bewildering. Forests are few and scattered in the tropical regions, and do not contain many different types of trees. A greater variety of small plants grow on the ground, however, and if we look very carefully, we may see a few invertebrates hiding and scrambling in the soil litter.

It’s quite a different story in the water. Invertebrates are abundant, and so are the many species of fish. But the fish are odd-looking, and very few resemble the species alive today. Aptly titled, the Devonian is known as the “Age of Fishes” in reference to their evolutionary explosion during this period.

Returning to solid ground, our eye catches a furtive movement: a creature scrambles across an open area, running crookedly, before splashing back into the water. This is one of the tetrapods, the first vertebrates to venture onto land. It doesn’t know it, of course, but this tetrapod will bring about a great evolutionary transformation, giving rise some 380 million years later to thousands of tetrapod species, including us!

Miguasha during Devonian time

Title: Miguasha during the Devonian Period
Author: Illustration by Philippe Janvier
Sources: Parc national de Miguasha
Year: 1996

Reconstruction of the Miguasha environment during the Devonian Period. Illustration by Philippe Janvier.

Evolutionary tree showing the main vertebrate groups

Title: Phylogenetic tree showing the main vertebrate groups
Author: Richard Cloutier and Hervé Lelièvre
Sources: Parc national de Miguasha
Year: 1998

With the exception of tetrapods, which only appeared at the end of the Devonian, vertebrates were represented by fishes during that geologic time period. In this phylogenetic tree showing the evolutionary relationships among vertebrates, the most primitive forms are at the top and the most evolved at the bottom. Only Myxinoidae and Arandaspidida lack Devonian representatives. The fish illustrations are by Philippe Janvier.