A team from the Paleontological Museum of San Pedro has unearthed a mastodon tusk measuring 2.34 meters, the longest ever documented in South America.
The fossil turned up at Estancia "El Silencio," in Bajo del Tala, part of San Pedro in Buenos Aires province roughly 170 kilometers from the capital, during one of the museum team's routine weekly prospecting trips along the area's exposed cliff faces. Alexis Celié spotted it first; museum director José Luis Aguilar and Walter Parra were also on the initial team, with a larger group -- Luis Dzickiewicz, Bruno Rolfo, Jorge Martínez, Augusto Moleón, Julio Simonini and Tomás Bronce -- handling the recovery.
The tusk belongs to Notiomastodon platensis, the mastodon species native to South America, and is estimated at roughly 500,000 years old, dating to the Middle-to-Upper Pleistocene. It measures 2.34 meters along its external curve, with a base diameter of about 20 centimeters tapering to 10 centimeters at the tip. "In none of the South American countries where Notiomastodon platensis is documented does a tusk exist with these characteristics," Aguilar said.
The specimen breaks a record the museum itself had held since 2006, when it recovered a 2.26-meter tusk from the same general area. It also surpasses a 2.05-meter tusk that naturalist Florentino Ameghino measured and recorded in 1876 -- a reference figure that had stood as a historical benchmark for the region for a century and a half. Researchers say no larger complete specimen has been published for South America.
Academic consultants Luciano Brambilla and Damián Ibarra, from the Universidad Nacional de Rosario, are working with the museum on the find. Its condition is unusually well preserved, which researchers say should allow for a detailed anatomical study, including analysis of the tusk's dentin microstructure -- layered growth patterns that can reveal how individual mastodons aged and grew in the Pampas region.
The tusk has been cleaned and consolidated for public display and goes on exhibit in Room 6 of the San Pedro museum starting the following weekend.