are more arrow-shaped and more sharply developed than in hadrosaurids. The unguals of digits II and IV are asymmetrical, with more elongated inner and lateral flanges, and longer upper regions. Classification Although a consensus on the exact taxonomic placement of this genus remains unreached, a 2010 study by Prieto-Márquez and Norell places the animal in a closely related outgroup to Hadrosauridae, based on a reassessment of its taxonomic status using a large-sample phylogenic analysis. Paleobiology Growth A comprehensive study on the bone microstructure of Asian hadrosauroid dinosaurs, evaluating its implications for the knowledge of growth strategies and evolution of gigantism in hadrosauroids, was published by Slowiak and colleagues in 2020 revealing that several growth strategies facilitated gigantism. Several hadrosaurs were histologically analyzed, including Barsboldia, Gobihadros, Saurolophus and ZPAL MgD-III/2-17, an indeterminate second species of hadrosauroid present in the Bayan Shireh Formation. The latter was slightly smaller than Gobihadros as seen on the developed external fundamental system (tightly-spaced LAGs that indicate adulthood) on the tibia. This hadrosauroid however, shares several traits with Gilmoreosaurus—most likely due to the proximities of both Bayan Shireh and Iren Dabasu formations—and the phylogenetic analyses performed recovered both hadrosaur species in a polytomy along with Lophorhothon and the indeterminate hadrosauroid. This analysis suggests similar growth size and rates in these species. Slowiak and colleagues noted that the growth trend within the Hadrosauroidea featured two important adaptations of bone microstructure similar to those of Eusauropoda. The first important adaptation was the decrease of secondary remodelling in the tibia, allowing the bone to bear higher tensions. This feature is thought to represent a biomechanical response to their increasing body-size evolution since the center of mass was concentrated on the pelvic area and therefore supported by well-developed hindlimbs. This explains the slender forelimbs in most hadrosaurs. A second adaptation was the disappearance of lines of arrested growth (LAGs). This feature, also reported in giant sauropods, allowed uninterrupted growth during ontogeny. Paleopathology In 2003, Rothschild and colleagues performed analyses in search for pathologies in several dinosaur specimens. Evidence of tumors, including hemangiomas, desmoplastic fibroma, metastatic cancer, and osteoblastoma were discovered in numerous specimens of Gilmoreosaurus by analyzing them through computerized tomography and fluoroscope screening. Several other hadrosaurids, including Brachylophosaurus, Edmontosaurus, and Bactrosaurus also tested positive. Although more than 10000 fossils were examined in this manner, the tumors were limited to Gilmoreosaurus and other hadrosaurs. The tumors were only found on caudal