Review

Journal of Vertebrate Paleontology, Vo. 20 No. 2, 27 June 2000, p. 411-413

DEVONIAN FISHES AND PLANTS OF MIGUASHA, QUEBEC, CANADA. Hans-Peter Schultze and Richard Cloutier (eds.) 1996. Verlag Dr. Friedrich Pfeil, München. ISBN 3-931516-03-2. 74 p., illus., $50.00 (cloth). – The Miguasha locality, in the Escuminac Formation of Late Devonian age, is one of the most important deposits of fossil fishes in the world. Known for more than a century (early names include "Baie des Chaleurs," "Escuminac Bay," and "Scaumenac Bay"), its most famous products, figured in innumerable texts and review papers, include the antiarch placoderm Bothriolepis canadensis and the rhipidistian crossopterygian Eusthenopteron foordi. Activities of more than 50 collectors produced thousands of specimens for European and North American museums and led to publication of hundreds of scientific papers.

The volume at hand, a collection of 24 refereed papers, represents the current state of knowledge by most of the researchers actively working with Miguasha fossils. Some of the papers deal primarily with the paleoenvironment. Most summarize systematics of a particular Miguasha fossil taxon. A few also present significant new anatomical data and phylogenetic interpretations. The breakdown by subject is geology and paleoenvironment (4); plants and invertebrates (5); agnathans (2); placoderms, acanthodians, and actinopterygians (1 each); sarcopterygians (6); and other subjects (4).

Many of us can recall reading in textbooks that particular Paleozoic fish taxa lived in fresh water and others in marine habitats. In fact, many of these generalizations are based on faulty assumptions and on early research that has not stood the test of time very well. Though many early workers thought the Miguasha rocks were of freshwater origin, more recently evidence seems to favor a brackish or marginal marine setting. The papers on geological and paleoenvironmental subjects (by Prichonet et al., Seguin, Chidiac, and Parent and Cloutier); on plants, invertebrates, and trace fossils (by Gensel and Barnett-Lawrence, McGregor, Jeram, Martens, and Maples); on coprolites (fossilized feces; by McAllister); and on vertebrate faunal comparisons (by Schultze and Cloutier) present a wide array of evidence bearing on the question of this deposit's paleoenvironment. We learn that Miguasha was at 15 degrees south latitude during the Late Devonian and that coprolites prove that there was much active predation during deposition of the formation. Relatively few beds in the deposit contain recognizable plants, invertebrates (including eurypterids and scorpions), or trace fossils; and none is of undoubted freshwater taxa, although the Conchostraca and the diverse palynoflora point in that direction. Except for the trace fossils, which do not occur in the same beds as well-preserved fishes, none is undoubtedly marine either. Chidiac tells us that the Boron concentration in the shales is intermediate between values for fresh and saltwater environments. Gensel and Barnett-Lawrence say that large, intact plant fossils imply proximity to their source. Schultze and Cloutier argue that the 20 species in 15 families of vertebrates include both freshwater and marine taxa. It would have been nice if the geological, botanical, and invertebrate evidence could have settled the question of the life habitat of the fishes, but unfortunately many possibilities remain open. A transitional (nearshore, estuarine, and/or intertidal) environment seems likely for much of the formation, but environments that are not fully marine are among the most difficult to identify in the Devonian fossil record.

The Late Devonian is indeed late relative to the origins of many major vertebrate groups, and several papers describe mostly derived members of their respective taxa. They (Janvier and Arsenault) are rare and not terribly well preserved, but large size range suggests continuous growth, contrary to the standard story. The "anaspids" (Janvier) of Miguasha are also rare, have some very strange anatomical features, and are described in three genera, one of which (Euphanerops) may be closely related to lampreys. The Placodermi (Vézina) include an arthrodire and of course the antiarch Bothriolepis canadensis, notable for its abundance, its reconstructed internal organs thanks to sediment infilling of its gut, and the extensive use that has been made of artists' restorations. The Acanthodii (Gagnier) are abundant and well preserved and include examples with three pairs of otoliths and with separate excurrent and incurrent nasal openings, two of the features that link them with bony fishes.

One of the most interesting articles is the paper by Arratia and Cloutier redescribing some features of the actinopterygian Cheirolepis canadensis and giving a new artist's restoration. This fish is one of the oldest, and most primitive, of the ray-fins known from complete skeletons. The authors remind us that similarly named skull bones in actinopterygians and sarcopterygians are not necessarily homologous. Their new restoration emphasizes the markedly lobed pectoral fin, the very long-based pelvic fin with 90-124 rays (!), the extremely small scales, and the very thin, numerous lepidotrichia in all of the fins. Of 19 actinopterygian synapomorphies whose state can be tested in this species, some 11 are lacking in Cheirolepis.

Articles on sarcopterygians comprise a third of the book. Those on Dipnoi and Actinistia (both are by Cloutier) and on Porolepiformes (Cloutier and Schultze) are especiaIly thorough. The intermediate-grade lungfishes Scaumenacia and Fleurantia, which still have separate dorsal, anal, and caudal fins, are well described and newly reconstructed. An epichordal lobe is documented in the caudal fin, though it is missing in many other fossil lungfishes. The primitive actinistian Miguashaia is even more interesting, as it is the most primitive known. Unlike later actinistians its caudal fin is heterocercal and has no supplementary lobe (epicaudal lobe or "flag"), the second dorsal fin is not lobed, the anal fin is only slightly lobed, and the fish's lepidotrichia are branched distally. Porolepiforms are heavily built, nonchoanate, predaceous sarcopterygians that are extremely common elements of many Devonian fish faunas. Of the two Miguasha porolepiforms described in this volume, one has all fins lobed except for the caudal, which is heterocercal but has epichordal rays, whereas the other has only its pectoral fins lobed and a less asymmetrical caudal fin.

Two papers deal with the rhipdistian Eusthenopteron foordi, that by Cloutier reviewing the nomenclatural history and that by Jarvik reviewing research on this fish. Perhaps the most-studied fossil fish, E. foordi has been the subject of nearly 200 papers in which it is given detailed treatment. Cloutier lists the papers by body part and designates a lectotype. Jarvik recounts his long acquaintance with a few well-preserved specimens of Eusthenopteron, including the preparation of the serial sections and of magnified wax models of internal features. Those wax models can still be found in the laboratories of the Naturhistoriska Riksmuseet, Stockholm. We see again Jarvik's stylized drawings, retouched photographs, and ideas about a diphyletic origin of tetrapods that have been published many times. Jarvik's paper is mainly of historical interest, and it is too bad that little of the modern work on this fish and its relatives is reviewed.

In this volume, I learned several things that were immediately useful in my teaching of ichthyology and fish paleontology classes and several other things that will be useful in my future research. The book is attractively produced, sturdily bound, and thoroughly edited. References are reasonably current, reaching into the 1990s. Illustrations are numerous and of very high quality. The price is certainly attractive; even better, Canadians can order the book directly from the Parc de Miguasha, C.P. 18, Nouvelle, Québec G0C 2E0, for only Canadian $38.00. It should be purchased by research libraries, by all with a special interest in fossil fishes, and by anyone curious about the material evidence upon which textbook restorations and generalizations are based.

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