Ornithopod dinosaur trackways (OA and OB) from the Lower Cretaceous Hekou Group at Yanguoxia (Gansu Province, China) have previously been described as “typical”—a term applied to contrast them with swim traces from the same surface rather than as a comprehensive behavioural assessment. Building on published trackway maps, this study uses an expanded suite of quantitative digital analytical tools to reassess ichnotaxonomic affinity, manus–pes relationships, and locomotor behaviour. Pes morphology in both trackways is consistent with the ornithopod ichnogenus Caririchnium, with closest affinity to Caririchnium lotus. However, quantitative analysis reveals crossover events, extreme pes-dominated heteropody, and unusual manus placement that depart substantially from expectations for typical quadrupedal ornithopod locomotion. These features are most parsimoniously explained by trackmaker locomotion under shallow subaqueous conditions, in which partial buoyancy reduced effective forelimb loading rather than reflecting anatomically reduced palmar surfaces. Exploratory statistical analysis indicates left–right asymmetry in pace and step parameters within the OA trackway, raising the possibility of lateralised locomotor behaviour. Together, these findings demonstrate that trackways previously regarded as typical may preserve unrecognised behavioural complexity, and that digital re-evaluation of legacy ichnological datasets can substantially refine interpretations of dinosaur locomotion.
Anthony Romilio (Tue,) studied this question.