James Henry Madsen

James "Jim" Henry Madsen Jr. (July 28, 1932 – November 28, 2009) was an American vertebrate paleontologist and geologist and main leader of excavations at the Cleveland-Lloyd Dinosaur Quarry in the 1960s. Madsen primarily worked to describe skeletons of Allosaurus from the quarry, eventually getting the site to become a National Natural Landmark in 1965 and a national monument after his death.

Biography James Henry Madsen Jr. was born to James Henry Madsen Sr. and Eva Anne Weidner on July 28, 1932, in Murray, Utah and married his wife Susan Sowles in 1956. Madsen Jr. had two children and four grandchildren, with a nephew and two nieces.

Public appearances Madsen was featured on 2 episodes of the History channel television series Jurassic Fight Club in 2008, where he spoke about Allosaurus, Ceratosaurus, and other Upper Jurassic American dinosaurs featured in the show.

Legacy In 2019, Madsen's student Daniel Chure and Mark Loewen described a new species of Allosaurus, which they named Allosaurus jimmadseni after Madsen's work on Allosaurus from Cleveland Lloyd Dinosaur Quarry.