The Arms You Carry

In 1965 an expedition to Mongolia led by Dr. Kielan-Jaworowska turned up some enormous arms. Though they went on to be named by Osmólska and Roniewicz as Deinocheirus in 1970, Kielan-Jaworowska reported the find in a 1966 report where she quickly described the remains. The arms appear to be almost pure fantasy, until you know the extant of the collected material. Typically extraordinarily fragmented remains contain an amount of speculation and scientific extrapolation, but the arms of Deinocheirus did not need either because the shoulder girdles, arms, and entire left hand were recovered. Additionally, dorsal vertebrae, gastralia, supporting neck bones (ceratobranchialia), and five ribs were also collected with the arms. Deinocheirus has been described as a possible ornithomimid dinosaur with a hypothetically omnivorous diet, though the claws have been interpreted as both belonging to a carnivore and an herbivore rather than strictly as omnivore appendages. The earliest works of Osmólska and Roniewicz favored a carnivorous diet, but as more research has been done, more wildly clawed dinosaurs, like Therizinosaurs, have been discovered, and more examples of Deinocheirus have been unearthed, the shift has been toward herbivory of taller plant materials. Given that most ornithomimid diets have lately been hypothesized to have been supplemented by insectivorous habits as well, a case for an omnivore lifestyle is logical. Regardless, Deinocheirus remains the most notable dinosaur find attributed to Zofia Kielan-Jaworowska during her expeditions to Mongolia. Tomorrow we will discuss some of her other discoveries in Mongolia that are a little less well known.