Title Information

SCHULTZE, Hans-Peter & Richard CLOUTIER (editors):

Devonian Fishes and Plants
of Miguasha, Quebec, Canada

Authors

Contents

Preface

The fossil site of Miguasha was discovered in 1842 and forgotten for a few decades. Its rediscovery in 1879 ignited many papers on fossil fishes by the Canadian paleontologist Whiteaves (LEMIEUX, this volume). Whiteaves referred to the site as the Baie des Chaleurs or Scaumenac Bay. For over a century, the site was known worldwide as "Scaumenac Bay." Since the creation of the Parc de Miguasha in 1985, Miguasha is the official geographic name for the site of the Escuminac Formation.

Fossil fishes from Miguasha immediately became the focus of phylogenetic discussions. As early as in 1892 COPE used Eusthenopteron from the Escuminac Formation as the key example relating tetrapods to osteolepiform crossopterygians in contrast to dipnoans. JARVIK focussed his lifelong research on Eusthenopteron so that the morphology and anatomy of this fossil fish is now known better than that of any other fossil and most Recent fishes (CLOUTIER, this volume). According to JARVIK (this volume), the osteolepiform Eusthenopteron presents already in the Devonian all basic tetrapod (including human) features. The fish in the Escuminac Formation closest to the tetrapod level is Elpistostege (SCHULTZE, this volume), which was first described as a tetrapod. Other than for the origin of tetrapods, the Escuminac fishes are crucial to our understanding of the origin of ray-finned fishes (ARRATIA and CLOUTIER, this volume) and coelacanths (CLOUTIER, this volume).

The placoderm Bothriolepis and the lungfish Scaumenacia are so common at the site and so well preserved that they became representatives of their respective groups in exhibits and teaching collections all over the world.

The richness of fossil fish at Miguasha drew expeditions and collectors from North America and Europe since 1879. Local collectors could supplement their income by selling fossil fishes. All that has stopped with the creation of the Parc de Miguasha. New finds are stored and curated now in the museum of the park (Musée d'Histoire naturelle de Miguasha) which has the largest collection of Escuminac fossils in the world (PARENT and CLOUTIER, this volume).

Since the descriptions of fossil fishes by WHITEAVES and of fossil plants by DAWSON, the number of taxa from Miguasha has more than tripled. Apart from ØRVIG's (1957) compilation of the fish assemblage and the sedimentological and paleoenvironmental interpretation by DINELEY and WILLIAMS (1968), this book presents the first comprehensive description of the history, geology, paleoenvironment and fossil content of the Upper Devonian site of Miguasha.

For the past 25 years, the paleoenvironment of the Escuminac Formation has generated a great deal of controversy. Originally interpreted as a lacustrine environment by DINELEY and WILLIAMS (1968), recent evidence suggests that the Escuminac Formation was deposited in a coastal marine environment (SCHULTZE, 1972; SCHULTZE and ARSENAULT, 1985; VÉZINA, 1991; SCHMITZ et al., 1991; HESSE and SAWH, 1992). The present account gathers further indications for a non-freshwater enviptd class="m">Although not as controversial as the paleoenvironment, the paleogeography of Miguasha also is a debated topic. During the Devonian, Miguasha was under equatorial climate as given by the position of paleocontinents (SEGUIN, this volume). The climatic conditions are reflected in the presence of terrestrial scorpions (Jeram, this volume) and luxurious plants which grew in the continental area near Miguasha (GENSEL and BARNETT-LAWRENCE, this volume).

Despite a rich palynomorph assemblage (McGREGOR, this volume), the megaflora shows only low diversity, an indication of distance from the coastline and/or destruction by transport. A new plant is documented for the Escuminac Formation (GENSEL and BARNETT-LAWRENCE, this volume). No palynomorphs suggesting marine conditions are reported by McGREGOR (this volume), but on the other hand acritarchs, yet to be described, are known from the lower part of the formation (SCHULTZE and CLOUTIER, this volume).

Although poor in invertebrate taxa, JERAM (this volume) and MARTENS (this volume) describe three arthropod taxa from the Escuminac Formation, including the first North American stylonuroid eurypterid. The first trace fossils are recorded from the Escuminac Formation; they indicate a marginal marine environment (MAPLES, this volume).

The entire vertebrate assemblage is revised, including some of its paleoecological interactions (McALLISTER, this volume). Twenty-one species are known, including four new taxa described in this volume (Osteostraci by JANVIER and ARSENAULT, Acanthodii by GAGNIER, Porolepiformes by CLOUTIER and SCHULTZE). The agnathans are unique and include the last survivors of the Paleozoic armored agnathans (JANVIER, this volume; JANVIER and ARSENAULT, this volume). The antiarch Bothriolepis (VÉZINA, this volume), the acanthodian Triazeugacanthus (GAGNIER, this volume), the lungfish Scaumenacia (CLOUTIER, this volume) and the osteolepiform Eusthenopteron are the most abundant taxa, the acanthodian Homalacanthus and the actinopterygian Cheirolepis are less common, and all other taxa are rather rare (PARENT and CLOUTIER, this volume). Most major groups of Devonian fishes are represented in Miguasha, with the exception of heterostracan agnathans, chondrichthyans and onychodontiforms.

The volume closes with a comparison of the fish assemblage of Miguasha with other contemporaneous assemblages (SCHULTZE and CLOUTIER). The ichthyofauna is highly endemic at the species level (20 of 21 species are unique), whereas at the generic level it is similar to far distant localities in Ellesmere Island, Scotland and Russia, and at the familial level it is reminiscent of one locality in Australia.

Sample pages

page 9	page 63	page 68	page 79	page 158
page 232	page 293	page 307	page 307	page 253

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