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 Sino-Japanese Dinosaur Project discovered the new early ceratopsian
Archaeoceratops, based on a
skull and two partial
skeletons, as well as many of the unique genera that form the
Mazongshan Dinosaur Fauna of the
Early Cretaceous of Gansu. Collaborations on the paleontology of the Mazongshan area continued with the Sino-American Mazongshan Dinosaur Project of 1997 to 2000, where the
University of Pennsylvania,
Carnegie Museum of Natural History and the IVPP collaborated. The Sino-American Dinosaur Project noticed the Yujingzi Basin in 1999 as a potential dinosaur-bearing locality, with the first dinosaur fossils discovered in 2000 by team members including Chinese paleontologist You Hailu of the Institute of Geology of
Chinese Academy of Geological Sciences (CAGS). You began collaborations with Chinese paleontologist Li Daqing of the Fossil Research and Development Center (FRDC) of Gansu Province in 2004, beginning excavations in the Yujingzi Basin and continuing those in the Gongpoquan Basin. Since the initial discoveries in the Yujingzi Basin, multiple new dinosaurs have been found, including the 2006 discovery of a partially complete articulated skull and skeleton, given the field number GSJB06-17-04. This specimen, now in the Gansu Geological Museum as GSGM-F00001, was then described in
2011 by You, Li, and Liu Weichang as the
holotype of the new taxon
Xuwulong yueluni. The
genus name is in honour of the pioneering geologist of the Gansu Province Wang Yue-lun, known by his
courtesy name "Xu-wu", with the
species name also in honour of Yue-lun. The Early Cretaceous deposits of the Yujingzi Basin are from
Xinminpu Group, with three distinct
facies, of which only the middle grey
sandstone preserves
Xuwulong. Carbon isotopes from the Yujingzi Basin sediments show sediments of the area are correlated to the
ocean anoxic event named the
Paquier Event, spanning the late
Aptian to early
Albian.
Radiometric dating of the
Xiagou Formation and
Zhonggou Formation elsewhere allows the sediments of the Yujingzi Basin to be identified, with the lower gray to green-gray
mudstones and
siltstones being the Xiagou Formation, while the red sandstones are the base of the Zhonggou.
Xuwulong can be placed in the upper Aptian in the Xiagou Formation through these correlations. ==References==