Virtual skeleton and body mass for revealing the life strategies of Sinosaurus

Abstract

ABSTRACT Sinosaurus from the Lufeng Basin, Yunnan Province, is the largest and most famous predatory dinosaur from the Early Jurassic in China. Although a number of specimens have been discovered in the past, no studies to date have focused exclusively on complete skeletal articulation, estimation of mass, or life strategies. Based on surface scans of a new well-preserved specimen, a digital skeleton of Sinosaurus was produced in two poses: osteologically neutral pose and extended pose. We estimated the possible living body mass by three volumetric-density methods, advocating the use of the expanding convex hulls method of 849.6 kg with the COM (0.41, 1.31, 0.00) as a more reliable result, which is greater than the mass of traditional regression formulas. The body shape and skull/body length suggested that Sinosaurus was a great runner, and this, combined with the weak crests and large forelimbs, further led to the conclusion that both the head and forelimbs were required to prey. This finding is also consistent with the finding that Sinosaurus has a moderate ability to metabolise body heat in the skin, as reflected by the surface/volume ratio.