Dino of the Week: Zupaysaurus

Type Species: Zupaysaurus rougieri

Classification: Dinosauria - Saurischia - Theropoda - Neotheropoda

Time Period: Late Triassic

Location: Argentina

Diet: Carnivore

Zupaysaurus lived during the Norian stage of the Late Triassic – between 228 to 208 mya – in what is now Argentina. It was found in what had been, in its times, a floodplain populated by several types of archosaurs and numerous sauropodomorph dinosaurs such as Riojasaurus. Zupaysaurus’ name is a combination of Quechua (Incan) and Greek words: the Incan word for ‘devil,’ supay, and the Greek word for ‘lizard,’ sauros. In Incan mythology, supay was the god of death and the ruler of the ukhu pacha, the Incan underworld. 

Zupaysaurus is known from only one specimen (a second, smaller specimen found near the specimen may or may not be the same kind of dinosaur). This bipedal predator had strong hind limbs and forelimbs designed to grasp. It was medium-sized, reaching to about thirteen feet in length from snout-to-tail. It had a rather long neck, and like the coelophysoids, Zupaysaurus had a kink in its snout between the premaxillary and maxillary bones of the upper jaw. 

note the (assumed) head-crests of Zupaysaurus

The original description of this theropod indicated that it had two thin parallel crests running along the top of its skull, similar to the later Dilophosaurus. The existence of these crests was based upon (a) skeletal anomaly – the lacrimal bones were at an upwards angle and may have served to anchor crests lost in the brutal fossilization process – and (b) the assumed relationship to Dilophosaurus, which undoubtedly had head crests (this same sort of logic has been used to attribute unsubstantiated crests to another Late Triassic theropod, Liliensternus). The presence of head-crests wouldn't be shocking, if only for the fact that many theropods - especially during the Jurassic Period - had such ornamentation. This doesn't mean, of course, that we should assume their presence on every theropod. In Zupaysaurus' case, further studies have indicated that the oddly-placed lacrimal bones may have ended up that way due to the fossilization process and weren’t a part of the living, breathing design; and other studies have indicated that Zupaysaurus, rather than being a predecessor to Dilophosaurus in the ‘dinosaur family tree,’ was actually part of a ‘sister clade’. If either one of these assertions is true, there’s no solid evidence for thin, parallel-running head crests. However, because artistic depictions tend towards the fanciful and eye-catching, it’s doubtful that the ‘non-crested’ version of Zupaysaurus will ever gain steam. 

a rendition of Zupaysaurus without the assumed head crests