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10 BULLETIN OF THE BIOLOGICAL SOCIETY OF WASHINGTON the fishes of French Guiana (Pellegrin 1908). Compendia of the freshwater fish species known from individual colonies, countries, or regions were not developed, let alone summaries of the fishes inhabiting in the numerous streams, rivers, and lakes across the shield. The dispersed literature prevented an appreciation of the scale of the diversity of the shield ichthyofauna. The first overview of the freshwater fishes of northeastern South America, including the Guiana Shield, was Eigenmann’s (1912) treatise on the freshwater fishes of British Guiana. Although Eigenmann sampled the fish fauna of only a comparatively small section of British Guiana, his collections were extensive for that era. In a series of papers, he and his students described 128 new species from those collections (Eigenmann 1912:133). Eigenmann’s monograph included data from his own collections, information from the literature, and records of fishes that originated on the Shield in various museums. Summary tables (Eigenmann 1912:64) detailed the fish species known from ten subunits that fall, at least in part, within the boundaries of the Guiana Shield (Río Orinoco basin, ‘‘West Coast’’ of British Guiana [5 Barima River basin], Rio Branco basin, Rupununi River, Lower Essequibo River, Lower Potaro River, Demerara River, Dutch Guiana [5 Suriname], and French Guiana [5 Guyane Française]). Eigenmann (1912) reported 493 species from those ten geographic units; a total that was in excess of the species reported to that time from the rivers of the Shield. These additional species were a function of two factors. His total included all of the fish species then known to inhabit the Río Orinoco; however, that vast river system extends far beyond the Shield boundaries with approximately only 40% of that watershed overlying the Shield. Many of the fish species known at the end of the first decade of the twentieth century from the Río Orinoco basin originated in the llanos (savannas) of the north central and western portions of the basin. Aquatic habitats and the fish faunas in these floodplain savanna settings differ dramatically from the ecosystems and fish communities of the more rapidly flowing rivers that drain the forested northern slope of the Guiana Shield. Further inflating Eigenmann’s species total was his inclusion of some primarily marine forms. Such species penetrate the lower reaches of the rivers draining the Guianas during periods of low river flow and consequent increased estuarine salinity. Few, if any, of these species are likely to range upriver onto the Shield even during the height of the dry season. The decades since Eigenmann’s monograph have seen numerous ichthyological collecting expeditions in many systems on the Shield. Two wide-ranging and productive collecting endeavors through that region during the first half of the twentieth century remain relatively poorly known. John Haseman, who collected throughout the Rio Branco basin and the southernmost portion of the Rupununi River system in 1912 and 1913, made the first of these. Haseman deposited these extensive collections in the Naturhistorisches Museum in Vienna where he studied them for a year in collaboration with Franz Steindachner. Nonetheless, only one major publication based on those collections was published (Steindachner 1915), most likely because of the onset of World War I, disruptions during and immediately after the conflict, and the death of Steindachner soon after the cessation of hostilities. Various revisionary studies in recent decades incorporated subsets of Haseman’s collection; nonetheless, much of the material is yet-to-be analyzed critically. The second collector, Carl Ternetz, sampled fishes through the Rio Negro, Río Casiquiare, and Río Orinoco basins during 1924 and 1925. Myers (1927:107) remarked that the collection was ‘‘a magnificent series of fishes, most of them hitherto unexplored systematically by an ichthyologist.’’ Notwithstanding the description of some new species collected by Ternetz in rivers of the shield by Myers (1927) and other authors and the use of portions of that collection in some studies (e.g., Myers & Weitzman 1960), most of the material remains unstudied, even after its transfer from Indiana University to the California Academy of Sciences. The 1960s brought a resurgence of major ichthyological collecting efforts in many of the river systems on the shield (e.g., the Brokopondo Project; Boeseman 1968:4), with the pace of these endeavors accelerating during recent decades. A compendium of these collecting efforts lies beyond the purpose and scope of this paper; however, as summarized in the next section many of these expeditions were integral to checklists, regional revisionary studies, and summaries of the ichthyofauna in river basins or regions of the Shield. State of Knowledge of the Shield Fish Fauna The nearly ten decades since the preparation of Eigenmann’s 1912 magnum opus saw numerous publications on fishes of the Guiana Shield. Many were revisionary studies of genera or families whose ranges extend far beyond the limits of the Shield, often across major portions of cis-Andean South America and in some instances into trans-Andean regions or occasionally Central America. Other publications were restricted to the members of a genus, subfamily, or family from a country within the Shield region (e.g., Suriname: Boeseman 1968, Nijssen 1970, Kullander & Nijssen 1989) or across a major portion of that area (e.g., Boeseman 1982). Relatively few of these papers involved broad surveys of an entire ichthyofauna in a river system or country on the Shield with those that
NUMBER 17 11 did so summarized below arranged by the geographic subdivisions in the checklist. Many include associated ecological and life history information for fish communities and individual species. Brazil, Pará (PA). The single publication of note from this region is Ferreira (1993) that summarized the results of intensive collecting efforts at sites within the Rio Trombetas, one of the major northern tributaries of the Amazon River east of the Rio Negro. Brazil, Roraima (RO). Ferreira et al. (1988) summarized the ichthyofauna at several closely situated localities in the Rio Mucajai, a tributary of the Rio Branco. More recently, Ferreira et al. (2007) provided detailed information on the ichthyofauna across the expanse of the Rio Branco basin, supplemented by numerous color photographs, discussions of habitats, and comments on the anthropogenic impact on the aquatic systems within the basin. French Guiana (FG). French Guiana has the most intensely studied ichthyofauna of any portion of the Guyana Shield. The first attempt to summarize information on the fishes of the entire department was that of Puyo (1949). Géry (1972) followed up with studies of the characiforms (his characoids) from the Guianas with a particular focus on French Guiana. Planquette et al. (1996), Keith et al. (2000), and Le Bail et al. (2000), in a groundbreaking series of publications, brought together information on the spectrum of the freshwater fish fauna in that department. Each species account includes a description, illustration, and comments on its biology. Distributions within and beyond French Guiana are discussed, and the sites of occurrences of the species in the department are plotted. Guyana (GU). Notwithstanding the title of the publication, Eigenmann’s (1912) monographic study was based primarily on collections from the northern portions of Guyana, in particular the Potaro River and lower courses of the Essequibo and Demerara rivers, albeit with that data supplemented with information from the literature. Hardman et al. (2002) reported on the fish fauna captured at Eigenmann’s collecting localities nine decades after his expedition and provided a checklist of the 272 species collected in that survey. Lowe (McConnell) (1964) included lists of fishes from the southern most reaches of the Essequibo River system along with observations on their ecology and on the movements of various species during the yearly flood and drought cycles. Watkins et al. (2004) provided a summary of the fishes of the Iwokrama Forest Reserve. Suriname (SU). The ichthyofauna of Suriname remains relatively poorly documented, with the listing of the freshwater fishes in the country by Eigenmann (1912:64–73) largely derived from literature information. Boeseman (1952, 1953, 1954) supplemented Eigenmann’s listing. Ouboter & Mol (1993) presented the most comprehensive published list of the freshwater fishes of Suriname. Kullander & Nijssen (1989) published a detailed analysis of the cichlids of Suriname. Venezuela, Amazonas (VA). The state of Amazonas, Venezuela, includes portions of the south-flowing Río Negro of the Amazon basin, the north-draining Río Orinoco and the entirety of the intervening Río Casiquiare. Mago-Leccia (1971) produced the first summary of the fishes of the Río Casiquiare. Lasso (1992), Royero et al. (1992), and Lasso et al. (2004a, 2004b) provided information on the fish faunas of various river systems within the state. Venezuela, Bolivar (BO). A series of studies treated the fish fauna of several right bank tributaries of the Río Orinoco that drain the northern slopes of the Guyana Shield. These included summaries of species in various basins, with those listings supplemented in some instances by information on fish biology and distribution. Significant publications on the ichthyofauna of the Río Caroni were published by Lasso (1991) and Lasso et al. (1991a, b) and for the Río Caura by Lasso et al. (2003a, b), Rodríquez-Olarte et al. (2003), and Vispo et al. (2003). The Río Cuyuni, a western tributary of the Essequibo River, drains the eastern portions of the Shield in the state of Bolivar. Machado-Allison et al. (2000) summarized the fish fauna of the Venezuelan portions of that river system. Lasso et al. (2004a) and Girardo et al. (2007) provide supplemental information on the ichthyofauna of that drainage basin. Ichthyofaunal Richness This checklist of fishes known from the water systems of the Guiana Shield includes 1168 species. Included in that total are representatives of 376 genera, 49 families, and 15 orders. Five orders are dominant in terms of number of species living on the shield and account for 96.7% of the species (Characiformes, 478 species and 41.0%; Siluriformes, 425 species and 36.4%; Perciformes, 126 species and 10.8%; Gymnotiformes, 52 species and 4.5%; Cyprinodontiformes, 47 species and 4.0%). This sum of 1168 species attests to the dramatic improvement of our knowledge of the freshwater fish fauna on the Shield in slightly less than a century since Eigenmann (1912) documented fewer than 500 species from that region. The 1168 species are approximately 4.1% of the 28,400 fish species recently estimated to be present in all marine and freshwater systems worldwide (Nelson 2006), a percentage that amply testifies to the striking diversity of the ichthyofauna within that region. All the more noteworthy is the species-level richness of the ichthyofauna within the context of the overall Neotropical freshwater fish fauna. According to a recent summary, approximately 5000 species of freshwater fishes occur across the
Page 1 and 2: BULLETIN of the Biological Society
Page 3 and 4: CHECKLIST OF THE FRESHWATER FISHES
Page 5 and 6: CONTENTS CONTRIBUTORS. . . ........
Page 7 and 8: Paulo H. F. Lucinda, Laboratório d
Page 10 and 11: In the face of the growing biodiver
Page 12 and 13: NUMBER 17 3 and are so unusual that
Page 14 and 15: NUMBER 17 5 Figure 2. A comparison
Page 17: History A vast complex of wetlands,
Page 21 and 22: NUMBER 17 13 composition of ichthyo
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Page 25 and 26: NUMBER 17 17 Guayana), Venezuela.
Page 28 and 29: The cornerstone of this project was
Page 30 and 31: NUMBER 17 23 Sarmento-Soares, L. M.
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Page 63 and 64: NUMBER 17 57 white and vice versa).
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INDEX TO ORDERS, FAMILIES, AND SUBF
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