An Ultimate Guide to Megapiranha: The Giant Piranha

Leave a comment / / Updated on: 24th September 2023

Name MeaningGiant PiranhaHeightN/A
PronunciationMEG-ah-pee-raan-haLength71 cm (2.3 feet)
EraCenozoic– Quaternary PeriodWeight9.97 kg (22 lbs)
ClassificationCharaciformes, Characidae, SerrasalminaeLocationArgentina, South America

Megapiranha Pictures

Megapiranha | Image via Dinopedia Fandom

The Megapiranha

Gage Beasley Prehistoric's Megapiranha Concept
Gage Beasley Prehistoric’s Megapiranha Concept

Even though its name, Megapiranha, might imply that this prehistoric fish was large, scientists have concluded that this extinct marine creature weighed just about 20-25 pounds and had an average length of 28 inches.

However, when you compare this size to the modern-day piranha’s weight of 3-4 pounds and length of 5-14 inches, you will agree that Megapiranha had a more considerable size.

This extinct serrasalmid characin fish lived about 8-10 million years ago, precisely during the Late Miocene sub-epoch of the Miocene Epoch.

And based on the fossil discovered in the Ituziangό Formation of Argentina in the 20th century, not only was this fish much more prominent than its modern-day cousin, it had a powerful jaw that packed a powerful biting force that could rival that of prehistoric whale-eating sharks, with a bite force of about 1,000 pounds per square inch, which is about 50 times its body weight.

With this powerful feature, it is apparent that Megapiranha was an apex predator of the Miocene epoch, despite its small size.

Reconstruction of the extinct Megapiranha
Reconstruction of the extinct Megapiranha | Apokryltaros via Wikipedia CC BY-SA 4.0

This fish could have preyed on not just fish and other creatures that wandered into its habitat but also crustaceans, giant turtles, and other shelled creatures.

The only recovered remains of Megapiranha comprise a zigzag tooth row and premaxillae, all from a single individual.

This means we only have limited information about this marine animal, although some inferences can be made based on its similarities with the modern-day piranha, especially the black piranha. 

Let us take a look at some interesting characteristics of Megapiranha.

Gage Beasley's Prehistoric Shirt Collection
Gage Beasley’s Prehistoric Shirt Collection
Gage Beasley's Prehistoric Plush Collection
Gage Beasley’s Prehistoric Plush Collection

Physical Characteristics

There are seven premaxillary teeth in Megapiranha’s holotype specimen, arranged in a zigzag pattern with some overlap. 

However, only three teeth—the third, fourth, and fifth— are wholly preserved. 

They also share similar morphology, although all three vary in size, with the fourth being the smallest and the third the largest. 

Megapiranha jaw
Megapiranha jaw | André-Philippe D. P. via Wikipedia CC BY-SA 3.0

The attachment scars also show the difference in size.

Furthermore, the first and third teeth comprise the inner row, while the others contain the outer row. 

Each discovered tooth features a single tooth crown shaped almost like an equilateral triangle and sits above a tooth constriction. 

Near the apex of the crown, the teeth become finely serrated and have slight labio-lingual compression.

Megapiranha’s teeth differed slightly from other fish in the same class. 

Scientists believe Megapiranha had a dentition that combined their close relatives, pacu and the extant piranha. 

While pacu has two rows of teeth on its jaw, primarily for crushing nuts, the piranha had a single row of well-serrated chisel-shaped teeth that were great for cutting flesh. 

A set of zigzag teeth in Megapiranha could mean that the two rows in pacu fused at a particular stage of evolution to form the single row found in modern piranha.

The discovered premaxilla is a bit straight, about 2.7 inches long, and has a rough outer surface that probably housed blood vessels and nerves. 

It also has a symphyseal joint which is interlocking.

Gage Beasley Prehistoric's Megapiranha Size Comparison Chart
Gage Beasley Prehistoric’s Megapiranha Size Comparison Chart

Based on an initial description of the giant piranha, the creature was said to have weighed about 161 pounds and reached a length of 37-50 inches, making it earn the title of the largest Serrasalmidae the world has ever recorded. 

However, after more recent research, with Serrasalmus rhombeus as a basis, it was finally concluded that Megapiranha most likely had an estimated length size of 28 inches and an average weight of 22 pounds.

Habitat and Distribution

Megapiranha’s fossil was unearthed in Argentina, South America, and is believed to have lived during the Miocene Era. 

During this period, the Parana and Amazon basin was one continuous habitat until the Andes Mountains rose and divided the two basins. 

Scientists believe that this division caused habitat loss and most likely led to the extinction of Megapiranha

It is also unclear whether the giant piranha lived in shoals like the extant red-bellied piranha fish.

Like the current piranha, Megapiranha most likely lived in warm freshwater. 

And since piranha are commonly found in the Amazon basin, it makes sense that Megapiranha favored the rivers of the Amazon basin, especially the Amazon River, the San Francisco River, and the Orinoco and Paraguay Rivers.

Behavior and Diet

Megapiranha on black background
Megapiranha on black background | Masonthetrex0916 via Dinopedia Fandom

While describing Megapiranha, Cione and colleagues suggested that the extinct fish’s dentition may not directly mean that the animal was carnivorous. 

They said it could mean that the animal fed on a wide range of food sources. 

Their conclusion was based on the fact that serrasalmids usually fall into different feeding categories (carnivorous, herbivorous, and omnivorous). 

In fact, some species of serrasalmids, like wimple piranha, are known to feed mainly on fish scales.

Another group of researchers suggests that the giant fish’s dentition could be a transitional form between slicing flesh and feeding on hard prey. 

To back up this theory, these scientists measured the bite force of Serrasalmus rhombeus (black piranha), an extant cousin of the Miocene animal. 

Skeletal reconstruction of Megapiranha
Skeletal reconstruction of Megapiranha | Augustios Paleo via Wikipedia CC BY-SA 4.0

It was discovered that the black piranha has a biting force three times its size, estimated to be about 72 pounds. 

This was said to be the strongest bite ever recorded for any kind of fish and even reptiles. 

Based on this estimation and the jaw size of Megapiranha, it was finally concluded that the extinct fish had a bite force that was probably four times higher than that of its smaller relative. 

The bite force of Megapiranha was calculated to be 279-1068 pounds. This force is almost as powerful as that of the great white shark. 

Further tests show that the giant piranha’s teeth were strong enough to penetrate the hard shell of a turtle, the armor of special catfish species, and the thick outer layer of a bovine femur. 

Therefore, they figured that the fish’s diet comprised these animals, including larger mammals.

Dentition of Megapiranha
Dentition of Megapiranha | Carl H. Eigenmann via Wikipedia Public Domain

With the shape of Megapiranha’s teeth, it is easy to infer that it used the tip of the teeth to cut through soft flesh and used the base of the tooth to absorb impact while crushing hard materials like bones, which is similar to how herbivorous pacus crush hard-shelled nuts and fruits. 

Still, this is only a hypothetical conclusion, as no skeletal remains bear the fish’s bite marks.

Also, since the dentition of Megapiranha lies between that of the herbivorous pacu of the Colossoma genus and the carnivorous piranha, it is difficult to conclude on the actual feeding routine of Megapiranha, although there is a high probability that it was a carnivorous animal like modern-day piranha.

Life Cycle

Megapiranha artist sketch
Megapiranha artist sketch | Image via Nature Rules Fandom

With the limited Megapiranha fossil available, deducing how long they lived is difficult. 

However, if we use modern piranha as a yardstick, it is possible that Megapiranhas had a lifespan of about five years or perhaps up to 10 years like the Red-Bellied Piranha. 

Females would most likely spawn at about one year of age.

Evolution and History

Megapiranha’s holotype was found in the early 20th century in the Ituziangό Formation of Argentina near the towns of Villa Urquiza and Paraná. 

It was a fragmental skeleton containing a premaxilla with multiple teeth. It was finally rediscovered in the 1980s by Alberto Luis Cione among the Museo de La Plata collection and described in 2009. 

Another single tooth was found in 1999 and has been categorized as part of this genus.

Image of Megapiranha and its skeleton
Image of Megapiranha and its skeleton | Image via Wikimedia Commons

Megapiranha is a combination of two words, “mega” and “piranha.” Mega refers to the fish’s big size, while piranha is the name given to carnivorous fish of Serrasalmidae family. 

The word itself is a derived Portuguese word that means “devil fish,” “tooth fish,” or “biting fish.” 

The type species is Megapiranha paranensis, and it got its name to reflect the fish’s place of origin near Paraná.

Interactions with Other Species

Megapiranha features a blend of some traits common among basal serrasalmids as well as those prevalent among derived members. 

For example, there are seven, not six, teeth and a subcircular attachment scar on the teeth, which is consistent with what is known from other members of the group. 

The triangular crown shape, fine serration, and slight labiolingual compression are more in line with true piranha teeth.

Megapiranha | Image via Ideas Fandom

Meanwhile, its interdigitating symphseal joint shows similarities to basal pacus like Mylossoma and Colossoma. 

However, its structure differs from extant forms, suggesting that it developed independently.

This combination of traits and features indicates an evolutionary trend among serrasalmids that focuses on a move from double-rowed dentition with wide teeth to the single row of flattened teeth common among piranhas.

Therefore, we can conclude that Megapiranha is an intermediate species of both sides, possessing triangular, slightly compressed teeth but with two relatively broad rows of teeth.

Furthermore, since Megapiranha’s dentition is strong enough to break through hard shells and armored fish, there is a probability that it was a carnivorous animal that preyed on armored catfish and turtles that co-existed with the fish at that time.

Cultural Significance

Megapiranha movie
Megapiranha movie | Image via TV Guide

Megapiranha is a popular fish today, mainly because of the movie titled after the fish. 

The horror movie “Mega Piranha” tells the story of a giant genetically modified piranha that escapes into the river and kills everything in its path. 

Over the years, modern piranhas have been mistaken for highly dangerous animals, and several movies have been released to that effect. 

However, piranhas are less dangerous than people think they are, and since we do not have Megapiranhas today, it is hard to know how they would have interacted with humans.

There are also Megapiranha toys available for sale, which is a major source of entertainment for kids.


Megapiranha, a powerful fish in its own right, lived in the Late Miocene Era and had a biting force that was almost 50 times its size. 

In comparison, the T. rex (Tyrannosaurus rex), the king of reptiles, had a bite force three times more powerful than that of the giant piranha. 

However, remember that T. rex was 100 times bigger than the marine creature. 

This means we can call Megapiranha the champion of a bite force in relation to size.

And based on findings, scientists have suggested that this fish is the evolutionary gap between pacu and the modern piranha. 

However, we can only draw limited conclusions due to insufficient fossils for research.


Was Megapiranha Aggressive?

If the modern piranha is anything to go by, Megapiranha was most likely an aggressive predator that loved to chase and ambush its prey. 

And its bite force means it would have loved to crush and break things.

Did Megapiranha Live in Oceans?

Megapiranha lived in the Parana and Amazon basin during the Miocene epoch, which means the animal preferred freshwater habitats.


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