Patagotitan

Chapter • Meet the dinosaur

Overview

Patagotitan mayorum ranks among the largest land animals ever recovered as a fossil. It was a titanosaur: a long-necked, four-legged plant eater with pillar-like limbs, a small low-slung skull and a long tapering tail carried clear of the ground rather than dragged. Its neck was built from massive but hollow vertebrae, honeycombed with air spaces linked to a bird-like system of air sacs, which kept the skeleton surprisingly light for its bulk. Published estimates put the body length at roughly 31 to 37 metres and the mass between 42 and 71 tonnes. The original figure of about 69 tonnes has been revised downward in several later analyses, and most researchers now favour a value somewhere in the middle of that range. Like all sauropods, Patagotitan moved on all fours and could not rear up in the way older artwork sometimes suggested. Its front feet lacked claws and formed semicircular columns of bone, while the hind feet bore short blunt claws. The teeth were narrow and pencil-shaped and were restricted to the front of the jaws. They worked as a rake for stripping vegetation rather than as chewing tools; food was swallowed whole and fermented for a long time in an enormous gut. The long neck let the animal sweep a wide feeding area without shifting its huge body, an energy-efficient strategy for a creature that needed hundreds of kilograms of plant matter every day. The discovery story begins in 2012, when a ranch worker named Aurelio Hernández spotted an enormous bone weathering out of the ground at La Flecha ranch near Trelew in Chubut Province, Argentine Patagonia. The Museo Paleontológico Egidio Feruglio sent a team led by José Luis Carballido and Diego Pol, and the excavations yielded more than 150 bones belonging to at least six individuals. The species was formally described in 2017; the genus name means roughly "Patagonian titan" and the species name mayorum honours the Mayo family, who owned the ranch. The bones come from the Cerro Barcino Formation and have been radiometrically dated to about 101.6 million years, placing the animal in the Early Cretaceous rather than the Late Cretaceous as first assumed. Because the skeletal material represents several individuals found together, growth stages can be compared directly, and all the specimens examined appear to have been young adults or close to fully grown. That means the true maximum size of the species may have been greater still. Full-scale casts of the skeleton have been displayed at the American Museum of Natural History in New York and, under the name Máximo, at the Field Museum in Chicago.

Chapter • Where it lived

Habitat

Patagotitan lived in what is now Chubut Province in Argentine Patagonia, roughly 102 to 100 million years ago during the Early Cretaceous (Albian stage). The fossils come from the Cerro Barcino Formation at La Flecha ranch, about 250 kilometres west of Trelew. The landscape was one of broad floodplains crossed by meandering rivers, with seasonal lakes and stands of conifers, ferns and cycads under a warm climate with pronounced dry spells. Volcanic ash from nearby eruptions buried the bones and made it possible to date the fossil-bearing layer with unusual precision.

Chapter • Family life

Breeding

Chapter • Wild behavior

Behavior & Ecology

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Chapter • Scientific place

Taxonomy