Harry Seeley

Harry Govier Seeley (18 February 1839 - 8 January 1909) was a British paleontologist who determined that dinosaurs fell into two major clades, the Saurischians and the Ornithischians, based on the nature of their pelvic bones and joints. He published his results in 1888, from a lecture he had delivered the previous year. Paleontologists of his time had been dividing the Dinosauria various ways, depending on the structure of their feet and the form of their teeth. Seeley's division, however, has stood the test of time, though, ironically, the birds have subsequently been found to descend, not from the "bird-hipped" Ornithischia, but from the "lizard-hipped" Saurischia. He found the two groups so distinct that he also argued for separate origins: not until the 1980s did new techniques of cladistic analysis show that both groups of dinosaurs really did have common ancestors in the Triassic. Seeley described and named numerous dinosaurs from their fossils in the course of his career.

His popular book on pterosaurs, Dragons of the Air (1901) found that birds and pterosaurs are closely parallel. Although his belief that they had a common origin has not proved correct, he upset Richard Owen's characterization of the pterosaurs as cold-blooded, sluggish gliders, and recognized them as warm-blooded active fliers.

Seeley was educated in London. He had been an assistant to Adam Sedgwick at the Woodwardian Museum, Cambridge, from 1859, and matriculated as a student at Sidney Sussex College, Cambridge in 1863. He turned down positions both with the British Museum and the Geological Survey of Britain to work on his own. Late in his career he accepted a position at King's College, Cambridge.