Archival data provides insights into the ambiguous track-maker gait from the Lower Jurassic (Sinemurian) Razorback beds, Queensland, Australia: evidence of theropod quadrupedalism?

The ichnological and palaeobiological interpretation of the first dinosaur tracks described from the Lower Jurassic (Sinemurian) Razorback beds, anthropogenic ‘fireclay caverns’ of Mount Morgan, Australia, is reviewed. This track sequence of two size categories has been widely accepted as having been formed by a theropod walking in an uncharacteristic quadrupedal stance. However, the morphology of the purported manus impression remained ambiguous due to the poor reproduction quality of the original image data. Here, we present previously unpublished archival photographic and replica material of this track surface. These clearly show the morphological details of the track series that are consistent with registration by two different sized bipedal track-makers. Overall, our findings illustrate that retained archival data can be pivotal in the resolution of palaeoichnological obscurities.

本文综述了澳大利亚摩根山（Mount Morgan）地区早侏罗世锡内穆阶（Sinemurian）雷泽尔贝克层（Razorback beds，该地层为人为成因的"耐火黏土洞穴"）中首批被记述的恐龙足迹的古足迹学与古生物学解读。这套分为两个尺寸类别的足迹序列，曾被广泛认为是由一只以反常四足行走姿态行进的兽脚类恐龙（theropod）所形成。然而，由于原始图像数据的复刻质量不佳，该据称的前足印痕的形态特征始终模糊不清。本文展示了该足迹面此前未公开的档案级摄影资料与复制品材料。这些资料清晰呈现了该足迹序列的形态细节，其与两种不同尺寸的两足造迹者所留下的足迹特征完全一致。综上，本研究结果表明，留存的档案资料可为解决古足迹学领域的未解争议提供关键支撑。