The Piraiba (Brachyplatystoma)

Brachyplatystoma is a genus of catfish from the family Pimelodidae. As the occasionally used common name goliath catfishes indicates, this genus includes some of the largest species of catfish, including the Piraíba, B. filamentosum, which reaches up to the region of 3.6 metres (12 ft) in length. Brachyplatystoma are found in the Amazon and Orinoco basins, and other tropical freshwater and brackish habitats in South America. Some species are migratory. These fish are important as food fish and, to some extent, aquarium fish.

This genus is characterized by two synapomorphies. One of these is modified jaw muscles. The other, more obvious trait, is only found in juveniles and subadults, in which the upper and lower rays of the caudal fin are extended into long filaments. B. vaillantii is the sister species to all other Brachyplatystoma, marked by differences in the skull, jaw, and other bones. The subgenus Malacobagrus is characterized by their derived lateral line, Weberian apparatus, a subquadrangular gill cover (as opposed to triangular in other species), and pectoral spine.

Fish of this genus are found in the Amazon, Orinoco, and The Guyanas in South America. The genus does not occur west or north of the Andes or in the Venezuelan Coastal Range. These fish generally inhabit areas that have a soft substrate, such as mud or sand.

These fish are usually caught with the use of long-lines or drift nets. They are also captured by harpoon as well as ropes with large fish hooks at the end.

There are currently seven recognized species in this genus (common name shown in second parentheses)

• Subgenus Brachyplatystoma:

• Brachyplatystoma juruense (Boulenger, 1898) (Zebra catfish, Juruense catfish, Gold Zebra Pim, False Tigrinus)

• Brachyplatystoma platynemum Boulenger, 1898 (Slobbering catfish)

• Brachyplatystoma tigrinum (Britski, 1981) (Tigerstriped catfish, Zebra shovelnose, Royal tiger shovelnose)

• Brachyplatystoma vaillantii (Valenciennes, 1840) (Laulao catfish, Piramutaba)