Which anatomical marker suggests Xiaotingia sat closer to the Deinonychosaurs branch?
Answer
The presence of an extensible second pedo-digit
A key feature used in phylogenetic analysis to argue for *Xiaotingia*'s placement closer to the dinosaurian branch, rather than fully within the avian lineage, is the structure of its foot. It possessed an extensible second pedo-digit. This specific type of digit structure is recognized as a hallmark characteristic of derived members within the Deinonychosaurs clade, a group that includes famous raptors like *Velociraptor*. The presence of this seemingly basal or non-avian trait strongly influenced interpretations that placed *Xiaotingia* nearer to the dromaeosaurs.
Related Questions
Roughly when did Xiaotingia zhengi exist based on Bathonian and Oxfordian stages?What was the estimated total length of the diminutive Xiaotingia?Which anatomical marker suggests Xiaotingia sat closer to the Deinonychosaurs branch?For which paleontologist was the specific epithet zhengi of Xiaotingia zhengi an honorific?What is the designation for the almost complete type specimen of Xiaotingia that includes the skull?How is the diet of Xiaotingia zhengi categorized by paleontologists?Besides the head and body, where else was Xiaotingia clearly covered in feathers?What capability might be suggested by the femur (84 mm) being longer than the humerus (71 mm) in Xiaotingia?Which groups did the initial analysis by Xu et al. suggest Xiaotingia grouped closely with, excluding traditional birds?From which geological formation in China was the specimen of Xiaotingia likely recovered?