Featured Research

from universities, journals, and other organizations

New Fossil Tells How Piranhas Got Their Teeth

Date:
June 26, 2009
Source:
National Evolutionary Synthesis Center (NESCent)
Summary:
Previously unknown fossil fish bridges the evolutionary gap between flesh-eating piranhas and their plant-eating cousins.

This photograph of the fossilized teeth and upper jaw of Megapiranha paranensis shows intermediate tooth arrangement between single-rowed piranhas and their double-rowed relatives. The fossil measures about 3 inches in length.
Credit: Photo courtesy of Mark Sabaj-Pιrez

How did piranhas — the legendary freshwater fish with the razor bite — get their telltale teeth? Researchers from Argentina, the United States and Venezuela have uncovered the jawbone of a striking transitional fossil that sheds light on this question. Named Megapiranha paranensis, this previously unknown fossil fish bridges the evolutionary gap between flesh-eating piranhas and their plant-eating cousins.

Present-day piranhas have a single row of triangular teeth, like the blade on a saw, explained the researchers. But their closest relatives — a group of fishes commonly known as pacus — have two rows of square teeth, presumably for crushing fruits and seeds. "In modern piranhas the teeth are arranged in a single file," said Wasila Dahdul, a visiting scientist at the National Evolutionary Synthesis Center in North Carolina. "But in the relatives of piranhas — which tend to be herbivorous fishes —the teeth are in two rows," said Dahdul.

Megapiranha shows an intermediate pattern: it's teeth are arranged in a zig-zag row. This suggests that the two rows in pacus were compressed to form a single row in piranhas. "It almost looks like the teeth are migrating from the second row into the first row," said John Lundberg, curator at the Academy of Natural Sciences in Philadelphia and a co-author of the study.

If this is so, Megapiranha may be an intermediate step in the long process that produced the piranha's distinctive bite. To find out where Megapiranha falls in the evolutionary tree for these fishes, Dahdul examined hundreds of specimens of modern piranhas and their relatives. "What's cool about this group of fish is their teeth have really distinctive features. A single tooth can tell you a lot about what species it is and what other fishes they're related to," said Dahdul. Her phylogenetic analysis confirms their hunch — Megapiranha seems to fit between piranhas and pacus in the fish family tree.

The Megapiranha fossil was originally collected in a riverside cliff in northeastern Argentina in the early 1900s, but remained unstudied until paleontologist Alberto Cione of Argentina's La Plata Museum rediscovered the startling specimen —an upper jaw with three unusually large and pointed teeth — in the 1980s in a museum drawer.

Cione's find suggests that Megapiranha lived between 8-10 million years ago in a South American river system known as the Paranα. But you wouldn't want to meet one today. If the jawbone of this fossil is any indication, Megapiranha was a big fish. By comparing the teeth and jaw to the same bones in present-day species, the researchers estimate that Megapiranha was up to 1 meter (3 feet) in length. That's at least four times as long as modern piranhas. Although no one is sure what Megapiranha ate, it probably had a diverse diet, said Cione.

Other riddles remain, however. "Piranhas have six teeth, but Megapiranha had seven," said Dahdul. "So what happened to the seventh tooth?"

"One of the teeth may have been lost," said Lundberg. "Or two of the original seven may have fused together over evolutionary time. It's an unanswered question. Maybe someday we'll find out."

The National Evolutionary Synthesis Center (NESCent) is an NSF-funded collaborative research center operated by Duke University, the University of North Carolina at Chapel Hill, and North Carolina State University.


Story Source:

The above story is based on materials provided by National Evolutionary Synthesis Center (NESCent). Note: Materials may be edited for content and length.


Journal Reference:

  1. Luis Cione et al. Megapiranha paranensis, a new genus and species of Serrasalmidae (Characiformes, Teleostei) from the upper Miocene of Argentina. Journal of Vertebrate Paleontology, 2009; 29 (2): 350 DOI: 10.1671/039.029.0221

Cite This Page:

National Evolutionary Synthesis Center (NESCent). "New Fossil Tells How Piranhas Got Their Teeth." ScienceDaily. ScienceDaily, 26 June 2009. <www.sciencedaily.com/releases/2009/06/090625201822.htm>.
National Evolutionary Synthesis Center (NESCent). (2009, June 26). New Fossil Tells How Piranhas Got Their Teeth. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2009/06/090625201822.htm
National Evolutionary Synthesis Center (NESCent). "New Fossil Tells How Piranhas Got Their Teeth." ScienceDaily. www.sciencedaily.com/releases/2009/06/090625201822.htm (accessed August 29, 2014).

Share This




More Plants & Animals News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) — State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Raw: Australian Sheep Gets Long Overdue Haircut

Raw: Australian Sheep Gets Long Overdue Haircut

AP (Aug. 28, 2014) — Hoping to break the record for world's wooliest, Shaun the sheep came up 10 pounds shy with his fleece weighing over 50 pounds after being shorn for the first time in years. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Minds Blown: Scientists Develop Fish That Walk On Land

Minds Blown: Scientists Develop Fish That Walk On Land

Newsy (Aug. 28, 2014) — Canadian scientists looking into the very first land animals took a fish out of water and forced it to walk. Video provided by Newsy
Powered by NewsLook.com
Fake Dogs Scare Real Geese from Wis. Park

Fake Dogs Scare Real Geese from Wis. Park

AP (Aug. 28, 2014) — Parks officials in Stevens Point, Wisconsin had a fowl problem. Canadian Geese were making a mess of a park, so officials enlisted cardboard versions of man's best friend. (Aug. 28) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins