James A. Jensen

Jensen was born in 1918 in Leamington, Utah[2] and developed an interest as a child exploring the desert and mountains with his father. While working in the now-defunct mining town of Mercur, Utah, he met his future wife, Marie M. Merrell.[3] Neither had finished high school, which limited their options.[4] Casting about for ways to begin their life, they decided to take advantage of the Federal Homestead Act and settled in Seward, Alaska which was still an unpopulated frontier. They married in 1941, and identified the plot of land that they intended to homestead.[5]

However, in anticipation of World War II, the U.S. Army moved into Seward in July, 1941, and started construction on Fort Raymond (Alaska). The massive influx of military personnel forced many civilians, including them, to return to the "Lower 48".[6] They settled in Salt Lake City, and had two sons. He went through a crash training program on the University of Utah campus to become a machinist and welder. Upon completing the brief program, he received an appointment as a civilian contractor from the federal government, then went to Hanford, WA to work on nuclear "Reactor B" pile of the Manhattan Project, after which he transferred to Pearl Harbor to work in the reconstruction. Jensen returned to Utah in 1945, where he worked at odd jobs such as washing machine repairman, creamery man, truck driver, ceramics, gunsmith, linoleum block printing, sculpting, welder, machinist, taxidermist, inventor, and writer.[7] During this time he met Arnie Lewis who worked at the Utah Field House of Natural History. They became friends and Lewis hired him to mount several birds of prey, later moving to the Museum of Comparative Zoology at Harvard University. In 1951, Jensen and family went to Seward, Alaska where he worked the next five years as a dockside longshoreman.[8]

Alfred Sherwood Romer, Harvard University, hired Jensen in 1956, at the suggestion of Arnie Lewis.[10] He was trained as a preparator in the Department of Vertebrate Paleontology of the Museum of Comparative Zoology. In addition to working on collections and exhibits for several departments, he participated in these collecting expeditions with Romer and Lewis during those five years:

• Nova Scotia[11]
• Florida - Thomas Farm[12][13]
• Ichigualasto in Argentina, the first of 2 such expeditions[14][15][16][17][18]
• Texas - Boone Ranch[19]
• Pennsylvania
• Ohio - Clark Hill[20]
• Drumheller, Alberta, Canada
• West Virginia - Greer Quarry[21]
• Montana - Hell Creek[22]
• Wyoming - McGrew Ranch[23]

Kronosaurus queenslandicus

Kronosaurus queenslandicus before glass was added to exhibit. 1957-8

In 1956, Romer decided to mount a Kronosaurus queenslandicus skeleton and had to obtain an unusually large amount of money to do the job. This was because the weight of the final mount was estimated to exceed the carrying capacity of the floor on which it would rest, due to the large amount of steel that would be used in preparing the mount. Therefore, architects drafted plans for a large I-beam to span the entire width of the building. Then two large holes were opened in the external walls and permanent mounts were created on each wall to hold the beam. Cranes then raised and inserted the beam into the holes so that it spanned the entire floor and was then secured to the two mounts. Romer Lewis and Jensen decided how to mount Kronosaurus. Jensen had plans showing how to mount a dinosaur without visible supports, plans which relied on his talents as an artist, sculptor, house framer, machinist and welder. Romer gave his approval to attempt a free standing mount. The plans were modified to suit the actual skeleton and Kronosaurus became the first mount done anywhere without visible structural members. All supporting bars, beams and sheets of metal and wood were integrated into or behind the bones. In addition to the unique method of concealing structural elements, Jensen used a curved back wall that had no corners to create the trompe d'oeil effect of a floating skeleton. There were no corners, vertical walls, or lines which would create the impression that the Kronosaurus was standing on the floor.[24]

When he went to Brigham Young University,[25] he helped develop the Paleontology program. He worked in the field every summer amassing a large collection of packaged bones in matrix. He continued to refine new mounting techniques, prepared specimens, describing some, and attempted unsuccessfully to obtain funding for an earth sciences museum. The bulk of his summer work was done in Western Colorado and Utah. In addition, he went on a second six-month expedition with Harvard University to Ichigualasto, Argentina, and went to Antarctica for three months in an expedition headed up by Ohio State University. His most significant finds in Argentina and Antarctica were the holotype of Probainognathus jenseni on Chañares Formation and a maxilla of a Lystrosaurus on Coalsack Bluff.

Jensen collected "bird" bones in the Dry Mesa Quarry and became interested in the changes necessary for species to move from terrestrial to arboreal life. For him the sine qua non of arboreal life was not feathers. It was the ability of organisms to actually live in trees. This required that they be able to grasp branches, to build nests where they laid eggs and then reared young, and to sleep on small branches for many hours. Feathers don't confer these advantages to the foot or ankle. He studied ankles and feet of a wide range of mammals including a recently deceased elephant which was brought to him in a refrigerated railroad car, birds, amphibians and any creatures with leg bones and feet. His conclusion was that evolution of the ankle and foot was the fundamental change which had to occur so that species could move permanently, regardless of feathers or not, from the ground into the branches of trees. His research over several years on ankles and feet of various fossil and extant species supported this hypothesis. Ultimately he wrote an article discussing his hypothesis and findings and illustrated it with his own drawings of bones. But out of pique at the time at the world of paleontology, he had the article translated into Japanese and then published it in a Japanese science magazine.[40]

In 1971, Jensen was granted an honorary doctorate by Brigham Young University.

• Jensen, James A. (1981) "A New Oldest Bird?" Anima: 33-39. Tokyo.
• Jensen, James A. (1985) "Uncompahgre dinosaur fauna: a preliminary report," Western North American Naturalist, Vol 45, No 4
• Jensen James A. (2001) The Road to Chilecito, Launceston, Tasmania: Queen Victoria Museum and Art Gallery. ISBN 978-0-9586203-5-2, OCLC 49797079.

Books

• Dinosaur Hunters by Kate McMullan, John R. Jones. New York: Random House, 1989. ISBN 978-0-394-81150-5, OCLC 18589091.
• Terrible Lizard: The First Dinosaur Hunters and the Birth of a New Science by Deborah Cadbury. New York : Holt, 2001. ISBN 978-0-8050-6772-9, OCLC 45637101.
• Drawing Out Leviathan: Dinosaurs and the Science Wars by Keith M. Parsons. Bloomington : Indiana University Press, 2001. ISBN 978-0-253-33937-9, OCLC 45873566
• Time Traveler: In Search of Dinosaurs and Other Fossils from Montana to Mongolia by Michael J. Novacek. New York: Farrar Straus Giroux; Godalming: Melia, 2003. ISBN 978-0-374-52876-8, OCLC 52878897
• Dinosaurs of Darkness by Thomas H. Rich and Patricia Vickers-Rich. Bloomington: Indiana University Press, 2000. ISBN 978-0-253-33773-3, OCLC 43552549

Articles

• Ancient Monarch of the Sea, in Natural History Magazine, June 1959, pp. 22–23

News

• "Fact or fiction", Deseret News, October 7, 2004
• Swensen, Jason (May 16, 2009), "Dinosaurs revisited in BYU paleontology museum", Church News

• Dinosaur Jim website - Consists of 186 unique URLs and more than 1,000 photos showing all of Jensen's digs while at Harvard University and Brigham Young University including his trip to Antarctica where he found Lystrosaurus.
• Museum Information, BYU Museum of Paleontology, Brigham Young University
• Jensen's entry on the Enchanted Learning site
• Kronosaurus queenslandicus: Ancient Monarch of the Seas
• "What is an Ultrasaurus?"
• Dinosaurs group 'S' on Wordquests
• Dinosaurs group 'T-Z' on Wordquests
• Kozak entry in the National Anthropological Archives