Futalognkosaurus (Wikimedia Commons).


Futalognkosaurus (indigenous/Greek for "giant chief lizard"); pronounced FOO-tah-LONK-oh-SORE-us


Woodlands of South America

Historical Period:

Late Cretaceous (80 million years ago)

Size and Weight:

About 100 feet long and 50-75 tons



Distinguishing Characteristics:

Quadrupedal posture; thick trunk; extremely long neck and tail

About Futalognkosaurus

You'd think it would be hard for a 100-foot-long dinosaur to keep a low profile, but the fact is that paleontologists are still digging up new genera. One of the latest examples is the oddly named Futalognkosaurus, 70 percent of whose skeleton has been reassembled from three fossilized specimens discovered in Patagonia (a region of South America). Technically, Futalognkosaurus is classified as a titanosaur (a type of lightly armored sauropod with a widespread distribution during the late Cretaceous period), and with 70 percent of its skeleton accounted for, some experts have hailed it as "the most complete giant dinosaur known so far." (Other titanosaurs, such as Argentinosaurus, may have been even bigger, but are represented by less complete fossil remains.)

Paleontologists have made significant process identifying the exact place of Futalognkosaurus on the titanosaur family tree. In 2008, researchers from South America proposed a new clade called "Lognkosauria," which includes both Futalognkosaurus, the closely related Mendozasaurus, and the possibly even more gigantic Puertasaurus. Tantalizingly, the same fossil site where these titanosaurs were discovered has also yielded the scattered bones of Megaraptor, a meat-eating dinosaur (not a true raptor) that may have preyed on the juveniles of Futalognkosaurus, or scavenged the bones of adults after they perished.