The type species, Niobrarasaurus coleii, was discovered and collected in 1930 by a geologist named Virgil Cole. It was originally described by Mehl in 1936 and named Hierosaurus coleii. It was then re-described as a new genus by Carpenter et al. in 1995. In 2002 the type specimen was transferred to the Sternberg Museum of Natural History, Hays, Kansas. It has been estimated to be 5 meters (16 feet) in length and around 227–453 kg (500–1.000 lbs) according to Thomas Holtz.[1]Paul gave a higher estimation of 6.5 meters (21.3 ft) and 4 tonnes (8.800 lbs).[2]
^Paul, Gregory S. (2010). The Princeton Field Guide to Dinosaurs. New Jersey: Princeton University Press. p. 230.
Carpenter, K., D. Dilkes, and D. B. Weishampel. 1995. The dinosaurs of the Niobrara Chalk Formation (upper Cretaceous, Kansas), Journal of Vertebrate Paleontology 15(2): 275–297.
Carpenter, K. and Everhart, M. J. 2007. Skull of the ankylosaur Niobrarasaurus coleii (Ankylosauria: Nodosauridae) from the Smoky Hill Chalk (Coniacian) of western Kansas. Transactions of the Kansas Academy of Science, 110(1/2): 1-9
Cole, V. B. 2007. Field notes regarding the 1930 discovery of the type specimen of Niobrarasaurus coleii, Gove County, Kansas. Transactions of the Kansas Academy of Science 110(1/2): 132–134.
Everhart, M. J. 2004. Notice of the transfer of the holotype specimen of Niobrarasaurus coleii (Ankylosauria; Nodosauridae) to the Sternberg Museum of Natural History. Transactions of the Kansas Academy of Science 107(3-4): 173–174.
Everhart, M. J. and S. A. Hamm. 2005. A new nodosaur specimen (Dinosauria: Nodosauridae) from the Smoky Hill Chalk (Upper Cretaceous) of western Kansas. Transactions of the Kansas Academy of Science 108(1/2): 15–21.
Liggett, G. A. 2005. A review of the dinosaurs from Kansas. Kansas Academy of Science. Transactions 108(1/2): 1–14.
Mehl, M. G. 1931. Aquatic dinosaur from the Niobrara of western Kansas. Bulletin of the Geological Society of America 42: 326–327.
Mehl, M. G. 1936. Hierosaurus coleii: a new aquatic dinosaur from the Niobrara Cretaceous of Kansas. Denison University Bulletin, Journal of the Scientific Laboratory 31: 1-20, 3 pls.