Pseudoplatystoma Bleeker

[[Genus Pseudoplatystoma Bleeker]]

As recently delimited, the family Pimelodidae (Long-Whiskered Catfishes) is now restricted to about 30 genera and 90 recognized and known but unnamed species (Lundberg and Littmann, 2003), all of which are found in the fresh waters of South America and the lower Isthmian regions. Pseudoplatystoma, the subject of this revision, is a monophyletic (Buitrago-Suarez Suárez) assemblage of boldly striped or spotted catfish populations placed in the family Pimelodidae. Standard references and catalogs record only three recognized species in the genus, P. fasciatum, P. corruscans and P. tigrinum (e.g., Burgess, 1989, Lundberg and Littmann, 2003). The diversity of this genus has been underestimated and their systematics are poorly known, in part, because geographic variation in morphology and coloration are displayed and because of a lack of taxonomic studies that firmly diagnose taxa and delimit species boundaries -a situation that has resulted in doubts of the status of such commercially important species as P. tigrinum. The absence of a critical review of the taxonomy reflects a lack of consensus on the number of species in the genus. Some authors consider P. tigrinum as a synonym or simply as a subspecies of P. fasciatum (Burgess, 1989). Two of the nominal species do not have a designated primary type (P. fasciatum and P. corruscans), and another has no specified type locality (P. tigrinum). Pseudoplatystoma fasciatum was considered a widespread species in classical works (e.g., Eigenmann & Eigenmann, 1889, Eigenmann, 1912; Fowler, 1915; Schultz, 1944; Gosline, 1945; Miles, 1947; Ringuelet et al., 1967; Mago-Leccia, 1970; Dahl, 1971, Lauzanne & Loubens, 1985), with a range embracing each major river in the neotropics. However, every major drainage population differs in body shape, pigmentation, and anatomy. For example, the population in the Magdalena River, which is currently considered P. fasciatum (Eigenmann, 1922; Dahl, 1971), is distinguished by having unbranched rays in the caudal fin, and a distinctive notch in the suspensorium, and has been isolated from the others species since the uplift of the Cordillera Oriental (13-11.5 mya, Hoorn et al, 1995).

The species of Pseudoplatystoma reach large sizes and are familiar due to their distinctively marked color pattern. They often are referred to in the vernacular as "Bagre rayado" or "Pintadillo" (tiger catfish or tigershovelnose). Species of the genus also are recognized by having a depressed head, an occipital process extending backward to contact the predorsal plate, and a very long fontanel. They are found in diverse habitats (Reid, 1983) including large rivers, lakes, side channels, flooded forests, and floating meadows (Reid, 1983; Burgess, 1989). The known distribution of Pseudoplatystoma includes the major river basins of South America: Paraná, Amazon, Orinoco, São Francisco, Magdalena, Rupununi, Essequibo, and Suriname (Burgess, 1989). None of the nominal species has been reported from the Pacific basin.

Species of Pseudoplatystoma are of considerable economic value and a few studies have summarized their general biology (e.g., Loubens & Panfili, 2000). Reports on general biology of Pseudoplatystoma cover reproduction and migration (Goulding, 1980; Reid, 1983; Loubens & Aquim, 1986; Kossowski & Madrid, 1986; Reyes & Huq, 1990; Goulding et al., 1996; Loubens & Panfili, 2000), fishery biology (Cordiviola, 1966; Valderrama et al., 1988), habitat and growth (Reid, 1983), basic morphology (Diogo, 2005), and as hosts for trichomycterids (Machado & Sazima, 1983).

This work has several major aims: to recognize and diagnose the species of Pseudoplatystoma, to apply correct names to the recognized species, to map their distributions, and to provide color photographs of fresh specimens taken in the field. Our taxonomic conclusions have significant implications for both the ornamental and commercial fishing industries in South America, because catch data have not distinguished the eight species recognized here and the potential impact of fishers on species of Pseudoplatystoma remains unknown, but certainly not inconsequential.