Zupaysaurus

Chapter • Meet the dinosaur

Overview

Zupaysaurus was a slender, long-legged predatory dinosaur roughly four to five and a half metres long, with body-mass estimates ranging from about 100 to 260 kilograms. Its build was typical of early theropods: a long, low skull filled with small, recurved, serrated teeth, a flexible neck, short arms with grasping hands, and a long stiffened tail that acted as a counterbalance over the hips. The snout carried a distinct notch between the premaxilla and maxilla, much like that of Coelophysis and Dilophosaurus. The original 2003 description reported a pair of thin, parallel crests running along the top of the skull, but a later re-examination of the specimen questioned this, suggesting the structures may be skull bones displaced during burial. Whether Zupaysaurus really wore head crests therefore remains genuinely open. No skin or filament impressions are preserved, and for theropods this early in the family tree we simply do not yet know whether a downy body covering was present.

Chapter • Where it lived

Habitat

Zupaysaurus lived in the Late Triassic, during the Norian stage roughly 215–205 million years ago. All known material comes from the Los Colorados Formation of La Rioja Province in northwestern Argentina, in the area of Quebrada de los Jachaleros. Those rocks were laid down by rivers and on broad floodplains under a warm climate with strongly seasonal dry spells — a landscape of sandy channels, temporary waterholes and stands of conifers and ferns along the banks. The same beds preserve long-necked plant-eaters such as Riojasaurus, Coloradisaurus and Lessemsaurus, along with an array of crocodile-line archosaurs including Riojasuchus and Neoaetosauroides.

Chapter • Wild behavior

Behavior & Ecology

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Chapter • Scientific place

Taxonomy