Pierre-Joseph van Beneden FRS FRSE FGS FZS (19 December 1809 – 8 January 1894) was a Belgian zoologist and paleontologist. Born in Mechelen, Belgium, he studied medicine at the State University of Leuven, and studied zoology in Paris under Georges Cuvier (1769–1832). In 1831 he became curator at the natural history museum in Leuven, and from 1836 until 1894 was a professor of zoology at the Catholic University of Leuven. In 1842 he became a member of the Académie des sciences de Belgique, becoming its President in 1881. In 1875 became a foreign member of the Royal Society of London and in 1884 an Honorary Fellow of the Royal Society of Edinburgh. In 1843 he established one of the world's first marine laboratories and aquariums. He was the father of biologist Edouard van Beneden (1846–1910). Pierre-Joseph van Beneden died in Leuven, Belgium. Van Beneden was a specialist in the field of parasitology, being known for his comprehensive studies on the development, transformation, and life-histories of parasitic worms. In 1858 a treatise on this subject won the Grand prix des sciences physiques of the Institut de France. It was published in the "International Scientific Series" (1875), under the title Les commensaux et les parasites dans le règne animal, and was translated into English and German. He did extensive research in marine biology, and in 1843 established an aquarium and marine laboratory in Ostend. With French zoologist Paul Gervais (1816–1879), he published an important work on extinct and living cetaceans titled Ostéographie des Cétacés, vivants et fossiles. His interest in this matter had begun during the excavations rendered necessary by the fortifying of Antwerp, when a number of bones of fossil whales were exposed to view. His papers on the extinct species found near Antwerp were published in the Annales du musée royal d'histoire naturelle de Brucelles, and with them was incorporated a description of the fossil seals which were discovered in the same area. He introduced the term mutualism in 1876.