Situé dans la région du Québec méridional, sur la côte sud-ouest de la péninsule gaspésienne, le parc national de Miguasha est un site paléontologique remarquable, considéré comme la meilleure illustration de la période du dévonien ou « âge des poissons ». Datée de 370 millions d'années, la formation d'Escuminac, dévonien supérieur, renferme cinq des six groupes de poissons fossiles associés à cette période. L'importance de ce site tient au fait qu'on y trouve la plus grande concentration de spécimens fossiles de poissons à nageoires charnues – en état exceptionnel de conservation – qui sont les ancêtres des premiers vertébrés terrestres respirant de l'air : les tétrapodes.
Parc national de Miguasha
Critère (viii) : Pour son témoignage sur la vie vertébrée et son illustration de l’«âge des poissons» du Dévonien, Miguasha est le site fossilifère le plus exceptionnel du monde. Le site est d’importance capitale car il occupe le premier rang mondial pour le nombre et la qualité de conservation des spécimens fossiles de Sarcoptérygiens qui sont les ancêtres des premiers vertébrés terrestres à quatre pattes et respirant de l’air – les tétrapodes.
[Uniquement en anglais]
The palaeontological site of Miguasha National Park, in south-eastern Quebec on the southern coast of the Gaspé Peninsula, is considered to be the world's most outstanding illustration of the Devonian period known as the 'Age of Fishes'.
Dating from 370 million years ago, the Upper Devonian Escuminac Formation represented here contains six of the eight fossil fish groups associated with this period. Its significance stems from the discovery of the highest number and best-preserved fossil specimens of the lobe-finned fishes that gave rise to the first four-legged, air-breathing terrestrial vertebrates - the tetrapods.
This 1 km wide formation extends for a distance of 8 km along the north shore of the Ristigouche River. The formation, extending 300-600 m underground, is represented by four distinct outcrops. The most important of these extends for a distance of 3 km and basically constitutes the park. Constituted essentially of grey rock sediments, the Escuminac Formation (dating from 350-375 million years ago) is composed of alternating layers of thick sandstone, silt and calcareous schists. The Fleurant Formation is found at the base of the Formation, while the summit is lined by the carboniferous Bonaventure Formation, whose reddish colour is the origin of the word Miguasha in the language of the Micmacs.
The flora and fauna fossils of Miguasha are particularly important in representing ichthyological fauna (fishes) of the Devonian period. Of the eight groups attached to this period, also known as the 'Age of Fishes', six are found at Miguasha, the other two being typically marine; this representation is uncommon among sites of the same age throughout the world. The site is also distinguished by invertebrates, plants and spore fossils (over 70 spore species) which, along with geochemical studies, have allowed a picture of the Devonian ecosystem to be constructed. Furthermore, the site is characterized by the exceptional condition of fossil remains, allowing, for example, study of soft body parts represented in gill imprints, digestive traces and cartilaginous elements of skeleton. Of particular importance is the presence of the crossopterygian group, typified by Eusthenopteron foordi and Elpistostege watsoni. Nicknamed the 'Prince of Miguasha', the Eusthenopteron, which share many characteristics with the tetrapods, have largely resulted in the focused attention of the international scientific community on the Escuminac Formation. Indeed, it was the discovery and study of Eusthenopteron which notably gave rise to the modern conception of evolution from fish to terrestrial tetrapod vertebrates.
Following taxa present an evolutive and phylogenetic interest: Archaeopteris belongs to Gymnosperma, Spermasposita is considered as the oldest flowering plant, while Petaloscorpio is the first terrestrial scorpion. The macroflora includes 10 species belonging to the first vascular plants of Devonian forests, and the microflora is composed of 80 spore species.
For more than a century, the flora and fauna fossils of Miguasha have been recognized as unique, manifest by the large numbers of scientists and collectors from Europe and America who have visited the Escuminac Formation. The site is particularly important in representing ichthyological fauna (fishes) of the Devonian period. Source : UNESCO/CLT/WHC