A primitive sauropodomorph from the upper Elliot Formation of Lesotho

Abstract

AbstractA well-preserved, articulated dinosaur skeleton from southern Africa is described. The specimen comes from the upper Elliot Formation (?Hettangian) of Ha Ralekoala (Lesotho) and represents a new species:Ignavusaurus rachelisgenus et species nova. A cladistic analysis suggests thatIgnavusaurusis more derived thanThecodontosaurus–Pantydraco, but more primitive thanEfraasia.Ignavusaurusindeed shares a number of unambiguous synapomorphies with the taxa more derived thanThecodontosaurus–Pantydraco, such as a fully open acetabulum, but it is more plesiomorphic thanEfraasiaand more derived sauropodomorphs as shown by the evidence of, for instance, the distal extremity of its tibia that is is longer (cranio-caudally) than wide (latero-medially). The discovery ofIgnavusaurusincreases the known diversity of the early sauropodomorph fauna of the upper Elliot Formation, which stands as one of the richest horizons in the world in this respect.