Lambert Beverly Halstead (13 June 1933 – 30 April 1991), who also went by Lambert Beverly Halstead Tarlo, was a British paleontologist and professor of Geology & Zoology and popularizer of science. He was noted for his candid theories of dinosaur sexual habits, and also for a prolonged assault on phylogenetic systematics (or "cladism", as he referred to it), in a series of letters and editorials to the journal Nature in the late 1970s and early 1980s. He was President of the Geologists' Association for 1990-91.