Modified Introduction from the upcoming volume:

 The Fresh and Brackish Water Fishes of Lower Guinea, West-Central Africa Poissons d'eux douces et saumâtres de Basee Guinée l'Afrique Ouest-Central. IRD Éditions, Paris.

Fig A-1
The Lower Guinean ichthyofaunal province comprises approximately 680,000 square kilometers of territory along the west coast of central Africa, following the arc of the Gulf of Guinea from the Cross River in eastern Nigeria, to the Chiloango River in the Angolan province of Cabinda. Extending from 7.4ºE, 7.4ºN to 14.8ºE, 5.4ºS, it includes the mainly coastal rivers draining much of eastern Nigeria, southern Cameroon, Equatorial Guinea, Gabon, south-western Republic of Congo, and Cabinda, all of which flow into the Atlantic Ocean north of the Congo River mouth. Dense forests and heavy seasonal rainfalls characterize this equatorial region. It is biogeographically distinctive with a fish fauna comprised of over 550 fresh water fishes with many species endemic to the region. In this publication we provide an account of the fresh and brackish water fishes of the region, describe their distributions, and provide practical keys to their identification. It is far from the final word on the subject and there is no doubt that much still remains to be discovered, but we hope that its publication will serve as a useful framework and stimulant for further studies.


An ichthyofaunal province is a region rather loosely defined by a relatively homogeneous fish fauna. The boundaries are far from clear cut, but largely correspond with current and historical drainage patterns of major river systems, which provide the natural routes for gene flow for freshwater fishes. Distributions are also influenced by habitat and climatic zones, elevation patterns, vegetation, and rainfall, as well as the geological history of the region. Since Boulenger's (1909) monumental Catalog of the Freshwater Fishes of Africa there have been no attempts to describe the fishes of the entire continent in a single work, and Boulenger (1905), Pellegrin (1911; 1921), Matthes (1964), Poll (1973), Roberts (1975), Lévêque (1997), and Thieme et al. (Thieme et al., 2005) have attempted to subdivide continental freshwater ecosystems in Africa into a number of ichthyofaunal provinces. The above figure shows the ten ichthyofaunal provinces of Africa proposed by Roberts (1975) and modified by Lévêque (1997) including the focal area for this volume, Lower Guinea. Each ichthyofaunal province has a somewhat characteristic assemblage of endemic species, and typical representation of taxonomic groups. While habitats may vary widely on the local level to include savannah and dense rainforest, mountains and lowlands, swamps, streams and rivers with highly varied geological and geographic features, fishes are more or less constrained by drainage pattern and historical connections. By limiting the scope of this book to the somewhat arbitrary boundaries of an ichthyofaunal province we are attempting to subdivide the continental fauna into smaller, more manageable units that reflect a biogeographic and evolutionary, rather than a geopolitical, history of the continent. We follow the organizational style of the faunal survey of West Africa (Lévêque et al., 1990-1992; Paugy et al., 2003), that included the Upper Guinean province and part of the Nilo-Sudan province that forms the boundary with Lower Guinea to the north (see Lévêque et al., 1990-1992). Lower Guinea is bounded on the south and east by the Congo River province, which has its own distinctive fauna. Teugels and Guégan (1994) have reviewed the history of fish exploration in the Congo, which after a period of relative inactivity is experiencing renewed attention.

Fig A-2
While the region's rich ichthyofauna was well known to local peoples, scientific exploration of Lower Guinea only really began in the mid 1800's as explorers, traders, administrators, and travelers started making collections from various localities within the province. In the nineteenth and early twentieth century, preserved specimens started to arrive in European and American museums for systematic investigation. Much of this material was studied by Günther, Boulenger, Pellegrin, Pappenheim, Steindachner, and others who established a basic taxonomic framework for the fauna. Collecting and exploration continued throughout the earlier part of the twentieth century with the beginning of additional biological studies of reproductive biology, development, ecology, comparative morphology and numerous taxonomic revisions. In the post-war period during the 1950's, 60's and 70's ichthyological work progressed substantially as new areas were explored and field stations were established to extend laboratory-based studies. Some of the major studies of this period include the description of important fish radiations in the crater lakes of western Cameroon by Trewavas (1974). Thys van den Audenaerde (1966) made extensive field trips to central and southern Cameroon. Géry (1965; 1968), Mahnert & Géry (1982) and others reported on fishes of the Ivindo River of Gabon. Daget (1978; 1979) and Daget and Depierre (1980) made important contributions to the fishes of the Sanaga River basin of Cameroon, and Román (1971) and Lasso et al (1998) made regional surveys of the fishes in Equatorial Guinea. More recently Teugels et al. (1991) explored the lower Kouilou River, Mamonekene and Teugels (1993) explored the Loémé near Mayumbe in the Republic of Congo, and Teugels et al. (1992) made collections and systematic studies of fishes of the Cross River of Cameroon. Stiassny et al. (1992) made a study of a small species flock of Tilapia with Schliewen et al (1994) making a strong case for sympatric speciation among these Tilapia arising in small crater lakes of Cameroon. Hopkins, Sullivan, Lavoué and others have made studies of the mormyrid fishes of Gabon (Hopkins et al., in press), and there has been intense collecting of diverse cyprinidont fishes throughout the entire region (see Amiet, 1987).

Fig A-3
The late twentieth and early twenty-first centuries have seen the development of new approaches, including molecular applications in systematics, ecological studies of species assemblages, and deepening concern about conservation. Teugels and Guégan (1994) reviewed the history of fish exploration of Lower Guinea and have given an overview of fish distributions. Kamdem (1993) and Kamdem and Teugels (1998; 1997; 1998) have studied the ecology of fishes in the Ntem River of Cameroon and Mbega and Teugels (2003) completed a study of fishes of the Lower Ogowe of Gabon. Most recently, increased mobility in many areas of Central West Africa has permitted finer scale geographic sampling of fishes in Lower Guinea, and techniques for sampling are constantly improving. Molecular and genetic techniques are being used to explore populations of fishes in this region (Arnegard et al., 2005; Arnegard and Hopkins, 2003; Lavoué, 2001; Lavoué et al., 2000; Lavoué et al., 2004; Lavoué and Sullivan, 2004; Lavoué et al., 2003; Sullivan et al., 2004; Sullivan et al., 2000; Sullivan et al., 2002). The latest era of fish exploration is starting to include studies focused on conservation of biodiversity (Theime et al., 2005). As human exploitation of natural resources increased, so too has the rate of loss of tropical rainforest in the region, currently estimated to be more than a million hectares per year (Brummet and Teugels, 2004). As natural habitats for freshwater fishes shrink in Africa there is ever more urgent concern for describing and conserving the existing biodiversity of Lower Guinea fishes (Brummet and Teugels, 2004).

An ichthyofaunal province is defined as much by its endemic species and higher taxa, as by the groups that dominate ecologically. The second figure shows a selection of representative endemic species from the province. The volume includes accounts for 573 species, 262 genera, and 45 families of fresh and brackish water species that regularly inhabit fresh waters. Most brackish water species are widespread in coastal inland waters but included among the freshwater species is a total of 310 endemic species and 16 genera unique to the province.

Lower Guinean fishes are dominated by three major ostariophysan groups: the Siluriformes (8 families, 24 genera, 107 species), Characiformes (3 families, 20 genera, and 53 species) and Cypriniformes (1 family, 79 species), and by three additional families; the Aplocheiildae (3 genera, 104 species), Cichlidae (21 genera, 74 species), and Mormyridae (15 genera, 41 species). Many of the smaller, colorful members of these groups are ornamental fishes sold in the thriving aquarium trade of Europe and North America.

The main river systems within the Lower Guinea ichthyofaunal province are, from Nigeria to the Congo mouth: the Cross, Wouri, Sanaga, Nyong, Ntem, M'bini (or Benito), Ogowe, Nyanga, Kouilou/Niari, and Chiloango in the third figure. The Cross, Mungo, Wouri, and the Sanaga, flow through savannah in the north while most remaining rivers flow through rainforests in the southern region. Most are blackwater rivers that discharge a light tea colored water with low conductivity, low pH, and low light penetration.

Except for in some of the northern rivers, typically Nilo-Sudanic species are largely absent in Lower Guinea. By contrast, many of the species in Lower Guinea are shared with the Congo River basin, especially those of the Ntem and Ivindo/Ogowe basins. For example, Mormyrops nigricans, Mormyrops zanclirostris, and Stomatorhinus (2 species) are typical of the Congo basin, but are also found in the Ogowe. Polypeterus retropinnis, Alestes macrophthalmus and Phenacogrammus urotaenia and others are shared between the Congo basin and the Lower Guinea province from the Ogowe northward. Thys van den Audenaerde (1966) discusses evidence for river capture among the headwaters of the Nyong, the Ntem, the Ja, and the Ivindo Rivers which might explain some of the current distribution patterns. Similarly, there is close proximity between the upper reaches of the Ivindo River in Gabon and the Ntem River, suggestive of a past river capture of the upper Ivindo by the Ntem.

The impending volume summarizes the current understanding of the fishes of Lower Guinea. Certainly it will be a work in progress, as new discoveries are being made each year and the process of taxonomic revision is accelerating with the advent of modern phylogenetic approaches and molecular techniques. The primary purpose of this compendium will be to help biologists, ichthyologists, conservationists, and fisheries managers identify the species they collect. We have attempted to make illustrations clear, and descriptions concise. In spite of these efforts, many of the groups require experience and considerable care to make accurate determinations. To help in this process we will provide keys for each of the groups included in the text. With few exceptions, species in our accounts have been formally described. However, for completeness we have chosen to include a handful of species that are still awaiting formal taxonomic description. These are referred to informally, and their accounts do not constitute valid descriptions for the purposes of zoological nomenclatural.

The book will be arranged taxonomically by family following Paugy et al (2003). Included will be a key to families, and a guide to, and glossary of, ichthyological anatomy and landmarks for taking counts and measurements used in the text. For each family a brief description of its characteristics and distribution will be provided as is the geographic distribution of included species. This will be followed by keys to the various genera, and by detailed keys to species, with descriptive accounts for each of them.