Scientists led by Dr. Marcelo Andrade of the Universidade Federal do Para report that they have discovered a new species of omnivorous freshwater fish in the Rio Madeira basin, Amazonia, and named it after the fictional secretive Latin American character Zorro.
Myloplus zorroi: female (upper image) and male. Image credit: Douglas Bastos / Andrade M.C. et al.
The newfound species belongs to Myloplus, a genus in the South American family Serrasalmidae.
Species in this genus are commonly known as ‘pacu’ in Brazil and ‘asitau’ or ‘kumaru’ in French Guiana.
They inhabit slow-or rapid-flowing rivers are of high commercial value, particularly in the Amazon.
The pacus are related to the piranha and have specialized dentition for crushing seeds.
The new pacu, named Myloplus zorroi, can grow to a length of 18.7 inches (47.5 cm).
Its basis color is reddish silver with darker markings running along the upper side of the body. The head is dark and the belly – pale yellow.
“Myloplus zorroi was incorrectly classified as an unknown species of the genus Tometes by Camargo and Giarrizzo in 2007,” Dr. Andrade and co-authors said.
“A more detailed analysis of its dentition and osteological features suggests that it is better classified as a species of Myloplus.”
Myloplus zorroi is known from Aripuanã (type locality) and Roosevelt rivers, two tributaries of the Rio Madeira basin.
“The type locality of Myloplus zorroi is a moderately to rapidly flowing, clear-water river running over rocky and sandy bottoms, with a depth ranging from approximately 6.5 feet (2 m) to at the most 26 feet (8 m), and a mean width of 1,050 feet (320 m),” the scientists said.
“The river is surrounded by extensive riparian vegetation that is mainly composed of ombrophilous forest and is located at an elevation of approximately 256 feet (78 m) above sea level. Water flow in the main channel is significantly reduced during the dry season (June–September), with most of the inflow restricted to small channels with rapids and extensive spread of rock outcrops scattered along the course of the main river.”
“The records of Myloplus zorroi in Rio Roosevelt were collected close to the vegetated edge, while the specimens collected in Rio Aripuanã were made around the rapids of Corredeira dos Periquitos and Salto de Dardanelos.”
Curiously enough, although the specific name of the new fish is chosen as a tribute to Mauricio Camargo-Zorro, a researcher at the Instituto Federal de Educacao, Ciencia e Tecnologia, in recognition of his invaluable contribution to the fish fauna inventory from the Marmelos Conservation Area, zorroi is also a playful reference to the Latin American fictional character Don Diego de la Vega and his secret identity hidden behind the nickname of Zorro.
The new species is described in a paper in the journal ZooKeys.
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Andrade M.C. et al. 2016. A new large species of Myloplus (Characiformes, Serrasalmidae) from the Rio Madeira basin, Brazil. ZooKeys 571: 153-167; doi: 10.3897/zookeys.571.5983
