Gongpoquansaurus

Gongpoquansaurus (meaning "Gongpoquan reptile") is an extinct genus of basal hadrosauroid dinosaur that was not formally named until 2014, while the name was a nomen nudum for many years previously. It is known from IVPP V.11333, a partial skull and postcranial skeleton. It was collected in 1992 at locality IVPP 9208–21, from the Albian Zhonggou Formation (Xinminpu Group), in Mazongshan, Gansu Province, China. The specimen was first described and named by Lü Junchang in 1997 as the third species of Probactrosaurus, Probactrosaurus mazongshanensis. Following its description, several studies found it to be less derived than the type species of Probactrosaurus in relation to Hadrosauridae. In 2014, the species was formally redescribed, and the describers erected Gongpoquansaurus.

==History of discovery== Expeditions into the Gansu Province of northwestern China began with the Sino-Swedish Expedition of 1930 to 1931, where discoveries of dinosaurs including the now-dubious early ceratopsian Microceratops sulcidens. These discoveries were followed by occasional observations of dinosaur bones in the Houhongquan Basin in the 1960s, and then the Gongpoquan Basin in 1986. Such observations led to the China-Canada Dinosaur Project taking a reconnaissance trip to the Gongpoquan Basin in 1988, but no further expeditions were led until the Sino-Japanese Silk Road Dinosaur Expedition of 1992 and 1993, led by Chinese paleontology Dong Zhiming of the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) and Japanese paleontologst Yoichi Azuma of the Fukui Prefectural Dinosaur Museum (FPDM). The first description of many of the newly-discovered fossils, from Mazongshan area of Gansu and the Turpan Basin of Xinjiang, was in 1997 as part of a book on the Sino-Japanese Silk Road expedition, following 1992 and 1993 excavations as well as a 1996 display of the fossils in Nagoya City Science Museum. One collection of these fossils, discovered in 1992 in a sandstone in the Mazongshan area, was described as the new species of the hadrosauroid Probactrosaurus, P. mazongshanensis. P. mazongshanensis was named in 1997 by Chinese paleontologist Lü Junchang for a partial skull, the holotype IVPP V. 11333, and a partial skeleton including almost all regions of the body, IVPP V. 11334.