vertebra by at least 50% of the centrum length. Skin impressions and osteoderms With the exception of a few sub-triangular plates found near the cervical and pectoral region, it completely lacks osteoderms on its body. Xu et al. (2001) identified a large bony plate present ventral to the right pelvic girdle and noted that it was covered in small tubercles. These tubercles are hexagonal and rhombic in shape, and have a diameter of about 0.5 mm. This ‘shell-like’ ventral bony plate was noted as being present in no other ankylosaur. Arbour et al. (2014b) re-examined and reinterpreted the ventral plate as skin impressions, with the tubercles instead representing flat polygonal scales. This reinterpretation is based mostly on the broken edges not revealing any bony histology. Classification Given the animal's unusual anatomy, Xu et al. (2001) had trouble identifying its relationship to other ankylosaurs. Their phylogenetic analysis loosely placed it into Nodosauridae. They conceded this binary division of Ankylosauria may not be entirely sound, meaning Liaoningosaurus could represent some third lineage. In 2004, paleontologist Matthew Vickaryous and colleagues left it under incertae sedis. A second cladistic analysis performed by Richard Thompson and colleagues in 2011 suggested that Liaoningosaurus is a basal ankylosaurid. This has become a consensus among phylogenetic analyses such as Arbour & Currie (2015) and Han et al. (2014), although a reduced strict consensus performed by Frauenfelder et al. (2022) recovered it within a polytomy, along with Cedarpelta and Chuanqilong, that is sister clade to both Ankylosauridae and Nodosauridae. The following cladogram is based on a 2015 phylogenetic analysis conducted by Arbour and Currie: Paleobiology Semiaquatic habits and diet Based on the second specimen that was described in 2016, Ji and colleagues proposed that Liaoningosaurus might have been adapted to a semiaquatic lifestyle. This is due to the presence of a 'shell-like' ventral bony plate that would have covered the entire ventral surface of the torso. The authors suggested that the structure would have functioned to protect the body from underwater attacks. However, a study by Arbour et al. (2014b) examined the shell-like structure and reinterpreted it as skin impressions with no bony internal texture. In contrast, Zheng (2018) suggested that the structure may have been formed by a ventral pelvic shield and an epidermal scale cover. Furthermore, Ji and colleagues argued that the lack of fusion between the spine and hip bones is an adaptation to a semiaquatic