Giganotosaurus

Chapter • Meet the dinosaur

Overview

Giganotosaurus was one of the largest predators ever to walk on land. It measured roughly 12–13 metres from snout to tail tip, and most published estimates place its weight between 6 and 8 tonnes. The skull was long and relatively narrow, around 1.5–1.8 metres, and lined with thin, blade-like teeth built for slicing flesh rather than crushing bone. It walked on two powerful hind legs with the backbone held horizontally and a long, muscular tail counterbalancing the body — the tail never dragged along the ground. The arms were short but ended in three clawed fingers. No skin impressions are known for Giganotosaurus itself, but close relatives preserve scales, and there is no evidence of feathers in carcharodontosaurids of this size. The brain was small relative to the body and unusually narrow, while the olfactory bulbs were well developed, suggesting a keen sense of smell. Biomechanical studies of the limb bones indicate that Giganotosaurus could move quickly for its bulk, with top-speed estimates of around 50 km/h, though such figures carry large uncertainties. Growth lines in the bones show that the animal grew fast and reached adult size within a couple of decades. As an apex predator it almost certainly targeted large plant-eaters. The same rocks preserve long-necked sauropods such as Andesaurus and Limaysaurus, and a hunter of this size could have delivered rapid, deep slashing bites to young or weakened individuals before backing off and letting blood loss do the work. Scavenging would have been part of the diet too. Because close relatives such as Mapusaurus have been found together in a single bone bed, some researchers have suggested that carcharodontosaurids sometimes gathered or even hunted in groups, but the idea remains debated. The first skeleton was found in 1993 by Rubén Darío Carolini, an amateur fossil hunter exploring the badlands near Villa El Chocón in Neuquén Province, Argentina, on a dune buggy. The find was remarkably complete for such a giant — about 70 percent of the skeleton was recovered. Rodolfo Coria and Leonardo Salgado formally described the species in 1995. The name means roughly "giant southern lizard", and the species name honours its discoverer. A jaw fragment from a second, larger individual later suggested that the species could rival or exceed Tyrannosaurus rex in size.

Chapter • Where it lived

Habitat

Giganotosaurus lived about 99.6–95 million years ago, in the earliest part of the Late Cretaceous (Cenomanian stage), in what is now northern Patagonia, Argentina. Its fossils come from the Candeleros Formation of the Neuquén Basin, near Villa El Chocón. The landscape was a broad floodplain crossed by braided rivers, with seasonal floods, dune fields and drier patches vegetated by conifers, ferns and cycads. Giganotosaurus shared this world with giant sauropods such as Andesaurus and Limaysaurus, smaller theropods, crocodyliforms and turtles.

Chapter • Wild behavior

Behavior & Ecology

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Chapter • Scientific place

Taxonomy