Megapiranha

Megapiranha is an extinct serrasalmid characin fish from the Late Miocene (8–10 million years ago) Ituzaingó Formation of Argentina, described in 2009. The type species is M. paranensis. It is thought to have been about in length and in weight. The holotype consists only of premaxillae and a zigzag tooth row; the rest of its body is unknown. This dentition is reminiscent of both the double-row seen in pacus, and the single row seen in the teeth of modern piranhas, suggesting that M. paranensis is a transitional form. Its bite force is estimated between .

==History and naming== The holotype of Megapiranha was discovered in an unknown locality of the Ituzaingó Formation, Argentina, in the early 20th century near the towns of Paraná and Villa Urquiza. The specimen, a fragment of the animal's premaxilla containing several teeth, was later rediscovered by Alberto Luis Cione in the collection of the Museo de La Plata. An isolated tooth discovered in 1999 has also been referred to this genus.