Tyrannotitan

Chapter • Meet the dinosaur

Overview

Tyrannotitan chubutensis was one of the largest land predators ever to walk in South America. It belonged to the carcharodontosaurids, the "shark-toothed" giant theropods related to Giganotosaurus and Carcharodontosaurus. Its body was that of a long, heavily muscled bipedal hunter, roughly 11.5–12.5 metres long with an estimated mass of about 5–7 tonnes. The skull was long and comparatively narrow, and the jaws carried blade-like, side-flattened teeth with serrated edges. The arms were short but powerful, ending in three clawed fingers. Despite the name, Tyrannotitan was not closely related to Tyrannosaurus at all; the name simply reflects its size and its role as an apex predator. No feather impressions are known from any carcharodontosaurid, and researchers assume the animal had scaly skin. Only two partial skeletons have been found, so much of Tyrannotitan's biology has to be inferred. The back vertebrae bear unusually tall neural spines, anchoring strong neck and back muscles that would have let the animal pull its head up and then drive it down into prey with great force. The tooth shape points to a slashing style of attack that opened long, bleeding wounds rather than crushing bone, exactly as in other carcharodontosaurids. The legs were long but very heavily built, so Tyrannotitan was probably no sprinter but rather a stamina walker capable of short bursts. Its food was almost certainly large plant-eaters. The same rock unit in Chubut has yielded the sauropod Chubutisaurus, and slightly higher in the sequence lies the giant titanosaur Patagotitan. A predator of this size could have attacked juveniles and sick adults of such giants, and would just as readily have scavenged carcasses left along the river valleys. Smaller ornithopods and young sauropods would have been easier targets. The species was described in 2005 by an Argentine team led by Fernando Novas, with Silvina de Valais, Patricia Vickers-Rich and Thomas Rich. The fossils come from the Cerro Barcino Formation of Chubut Province in Patagonia, and consist of two individuals: a holotype including jaw fragments, teeth, vertebrae, ribs, and parts of the pelvis and hind limb, plus a second, slightly smaller specimen. The genus name means roughly "tyrant titan", while the species name refers to Chubut.

Chapter • Where it lived

Habitat

Tyrannotitan lived in the Early Cretaceous, during the Aptian stage roughly 121–113 million years ago. Its fossils come from the Cerro Barcino Formation (Cerro Castaño Member) in Chubut Province, Argentine Patagonia. The setting was a semi-arid to seasonally wet inland landscape of floodplains, ephemeral streams, lakes and open ground with conifers, ferns and cycads. Volcanic ash from nearby eruptions helped preserve both plants and bones, and the same environment supported large sauropods, smaller theropods and early turtles.

Chapter • Wild behavior

Behavior & Ecology

Did you know?

Chapter • Scientific place

Taxonomy