Gryposaurus, meaning “hook-nosed lizard,” was a duck-billed dinosaur belonging to the family Hadrosauridae, which includes the well-known species Edmontosaurus, Lambeosaurus, Parasaurolophus, Corythosaurus and Saurolophus. Hadrosaurs were herbivores and the most successful and widespread dinosaur group during the Late Cretaceous Period. Taking full advantage of their ability to shift from quadrupedal to bipedal postures, they spent their days consuming vast amounts of the lush vegetation that grew in abundance in an area that was at the time covered in lakes, ponds, rivers and streams. Their most distinctive feature was their cranium, which displayed a diverse development of bird-like beaks and ornate head crests, with Gryposaurus being distinguished by its distinctly arched nasal bones and a flattened mouth area resembling the bill of a duck.

An adult Gryposaurus measured on average 25-26 feet in length, however the present specimen comes in at 8 feet, 10 ½ inches in length, meaning that it was only a baby when it died. Found as part of a mass mortality event, it is very likely that its death was the result of a devastating flash flood, as there are no signs of disease, and no bite marks that would indicate that it fell prey to a larger predator, a common fate for juvenile dinosaurs. This remarkable discovery is an incredibly rare and important find, especially as the crucial diagnostic portions of the skull, being the arched nasal bones, are intact (which has not been the case for many earlier specimens, making the description of the genus difficult).

The dig site was especially tricky, as the specimen was found 100 feet up in a cliff face with 65 feet of overburden above it. To ensure the preservation of the specimen, as well as the safety of the field paleontologists carrying out the excavation, the overburden and then the specimen itself were painstakingly dug out by hand over a three-year period. The fossil elements and their surrounding rock matrixes were then encased in plaster field jackets, before being brought back to the lab, where they were meticulously extracted using specialized tools. The fossil elements were then carefully sorted and organized before the work was undertaken to restore and mount them as they are now exhibited. All fossil elements were fully documented before restoration and mounting, and the specimen comes with full documentation demonstrating authenticity and legality of ownership.

What we know about Gryposaurus is based on a small handful of partial skulls and skeletons found in the Dinosaur Park Formation in Alberta, Canada, and the Lower Two Medicine Formation in the state of Montana, United States. Due to the rarity of complete specimens, in particular those with complete skull material, there has long been ambiguity on the description of the fossils, with the genus Gryposaurus and Kritosaurus initially being considered two separate genus, and then later only a single genus. The first find to be described as Gryposaurus was in 1913, when paleontologist George Fryer Sternberg (1883-1969) discovered specimen NMC 2278 (now part of the collections of the National Museums of Canada) along the Red Deer River in the Alberta Dinosaur Park Formation. The find was subsequently described by paleontologist Lawrence Morris Lambe (1863-1919) in his 1914 paper published by The Ottawa Naturalist, where he dubbed it Gryposaurus notabilis. The great fossil hunter Barnum Brown (1873-1963), renowned for having discovered the first ever fossil of a Tyrannosaurus rex, had some years earlier discovered a partial skull similar in size and shape to Gryposaurus in New Mexico. The skull, which was missing the snout, was dubbed by him Kritosaurus, as he believed it to be a new genus. However, after reading Lambe’s description of Gryposaurus, Brown proposed (along with paleontologist Charles Gilmore of the US National Museum of Natural History), that the two genus were actually one. A nearly complete skeleton found in the Alberta Dinosaur Park Formation in 1919 was named Kritosaurus incurvimanus rather than Gryposaurus incurvimanus by paleontologist William Park (though he did still leave Gryposaurus notabilis in its own genus), as, like the skull found by Barnum, the diagnostic portion of the incurvimanus skull was missing, making it impossible to compare and differentiate from Gryposaurus notabilis. In 1942, paleontologists Richard Swann Lull and Nelda E. Wright published their highly influential monograph Hadrosaurian Dinosaurs of North America, resulting in Kritosaurus being favored over Gryposaurus for the next half century, until even further research and review of materials in the 1990s brought the use of Gryposaurus back into favor, with this research continuing today to identify more specimens and further our understanding of this important dinosaur.

• Creisler, Benjamin S. (2007). "Deciphering duckbills". In Carpenter, Kenneth (ed.). Horns and Beaks: Ceratopsian and Ornithopod Dinosaurs. Bloomington and Indianapolis: Indiana University Press. pp. 185–210
• Hopson, James A. (1975). "The evolution of cranial display structures in hadrosaurian dinosaurs". Paleobiology. 1 (1): 21–43
• L. M. Lambe. 1914. "On Gryposaurus notabilis, a new genus and species of trachodont dinosaur from the Belly River Formation of Alberta, with a description of the skull of Chasmosaurus belli." The Ottawa Naturalist 27(11):145-155
• Lull, Richard Swann; Wright, Nelda E. (1942). "Hadrosaurian Dinosaurs of North America. Geological Society of America Special Paper 40." Geological Society of America. p. 21; pp. 110-117; pp. 164-172; p. 226
• Parks, William A. (1919). "Preliminary description of a new species of trachodont dinosaur of the genus Kritosaurus, Kritosaurus incurvimanus". Transactions of the Royal Society of Canada. Series 3. 13 (4): 51–59.
• Weishampel, David B.; Horner, Jack R. (1990). "Hadrosauridae". In Weishampel, David B.; Dodson, Peter; Osmólska Halszka (eds.). The Dinosauria (1st ed.). Berkeley: University of California Press. pp. 534–561

鈎鼻龍又名「鉤鼻蜥蜴」，屬於鴨嘴龍科的恐龍，其中包括著名的埃德蒙頓龍、蘭伯龍、副櫛龍、冠龍及櫛龍，為草食動物，是白堊紀晚期最成功，分布最廣的龍屬族群。鉤角龍善用從四足姿勢轉換到雙足姿勢，故每天能大量進食當時生長在湖泊、池塘、河流和溪流中的茂盛植被。該龍屬最顯著的特徵是其顱骨，可呈現發育多樣的形態，如鳥喙和壯觀華麗的頭冠。另外，牠們亦以鼻骨呈明顯弧形，以及其貌似鴨嘴的扁平嘴部見稱。

成年鈎鼻龍平均長約25至26英尺，但此標本長度為8英尺10.5英寸，意味此恐龍死亡時仍是嬰兒，估計死於由洪水導致的大規模致命事件。其身上沒有患病跡象，亦沒有咬痕，曾為較大掠食者的獵物機會不高，然而這卻是很多幼年恐龍的常見命運。這標本極為罕見重要，尤其是其拱形鼻骨，為關鍵的頭骨診斷部分，維持完好無損，實屬難得。（完整的頭骨不常見於許多早期標本，因而令描述該屬變得困難）。

因為標本在懸崖上100英尺處發現，上面有65英尺覆蓋層，所以挖掘尤其棘手。為確保標本得以保存，及考慮到進行挖掘的野外古生物學家的安全，所以要使用人手仔細挖掘覆蓋層及標本，歷時整整三年多始完成。化石元素及其周圍的岩石基體隨後以野外石膏夾克包裹，然後帶回實驗室，以專業工具小心提取，再對化石元素仔細進行排序整理和修復重組，才得以成就眼前展品。在修復和重組之前，所有化石元素均經詳盡記錄，該標本附帶完整文檔，證明其真實性和合法擁有權。

我們對鈎鼻龍的了解基於在加拿大艾伯塔省恐龍公園地層和美國蒙大拿州下二醫學地層中發現的少數部分頭骨和骨骼。由於完整標本，特別是具有完整頭骨材料的標本極為稀有，所以長期以來人們對此恐龍的描述一直未盡詳細。最初鈎鼻龍屬和分離龍屬被視為兩個不同品種，後來又定為同一個屬。鈎鼻龍首次被發現於1913年，當時古生物學家喬治·弗萊爾·斯特恩伯格（1883 至 1969年）在加拿大艾伯塔省紅鹿河的恐龍公園地層發現了標本NMC 2278（現屬加拿大國家博物館收藏）。隨後，古生物學家勞倫斯·莫里斯·藍伯（1863 至 1919年）於1914年在《渥太華博物學家》發表的論文中描述了這一發現，並將其稱為鈎鼻龍屬。在此之數年前，以發現了世界首副暴龍化石而聞名的傳奇化石獵人巴納姆·布朗（1873 至 1963 年）在新墨西哥州發現了一個與鈎鼻龍大小形狀相似的部分頭骨。由於頭骨缺少吻部，故該發現被辨別為分離龍，於當時被視為一種新的龍屬。然而，在閱讀過藍伯對鈎鼻龍的描述之後，布朗與美國國家自然歷史博物館古生物學家查爾斯·吉爾摩共同主張，兩個化石標本實際上是同一龍屬。1919年，人們在艾伯塔省恐龍公園地層中發現了近乎完整骨架，古生物學家威廉·帕克將其命名為分離龍，而非鈎鼻龍 ，儘管他仍將鈎鼻龍保留在其本屬中。該骨架就像巴納姆·布朗發現的頭骨一樣，因缺乏關鍵的頭骨診斷部分，以致無法與鈎鼻龍屬比較區分，因而被錯誤歸屬。1942年，古生物學家理查德·斯旺·拉爾和內爾達·萊特發表了極具影響力的論文《北美洲鴨嘴龍》，導致其後半個世紀，人們大多傾向使用分離龍，而非鈎鼻龍來稱呼這種恐龍。直到1990年代，經過進一步研究和文獻回顧，鈎鼻龍開始重新受到青睞。這項研究持續至今，望識別更多標本，從而幫助人們更深入了解這重要的龍屬。