Anders Erik Vilhelm Jarvik (30 November 1907 – 11 January 1998) was a Swedish paleontologist who worked extensively on the sarcopterygian (or lobe-finned) fish Eusthenopteron. In a career that spanned some 60 years, Jarvik produced some of the most detailed anatomical work on this fish, making it arguably the best known fossil vertebrate. Jarvik was born at a farm in Utby Parish near Mariestad in northern Västergötland. He studied botany, zoology, geology, and paleontology at Uppsala University, where he took his licentiate's degree in 1937. In 1942, he completed his PhD with the dissertation On the structure of the snout of Crossopterygians and lower Gnathostomes in general. He participated in the Greenland expedition of Gunnar Säve-Söderbergh in 1932 and was appointed assistant in the Department of Palaeozoology of the Swedish Museum of Natural History in Stockholm in 1937; he eventually succeeded Erik Stensiö as professor and head of the department in 1960, retiring in 1972. Research Jarvik's research concerned mainly the sarcopterygian fishes. His main interests were in the so-called "rhipidistian" sarcopterygian fishes, which he held to be divided into two groups: the Osteolepiformes and the Porolepiformes. He published several solidly descriptive works on Devonian sarcopterygians. Work on Eusthenopteron In particular, he conducted detailed anatomical studies of the cranium of Eusthenopteron foordi using a serial-section technique introduced by William Johnson Sollas and applied to fossil fishes by Erik Stensiö. A fossil of limited external quality was sectioned by grinding off a thin section, photographing the grind-off end and repeat the process until the whole fossil was worked through. The internal structures would then show up on long series of photographs. Working in the day before computer simulations, models was made by projecting reversal film on a board, and cut thin wax plates to match. The sticky wax plates could then be assembled to a three-dimensional scaled-up model of the skull, complete with internal structures such as nerve channels and other internal hollows rarely seen in fossils. Further section to the cranium could easily be made by cutting the wax model at the desired angle. Due to the sticky nature of the wax used, a sectioned skull was put back together by simply pressing the two sections back together. This technique was also applied to the cranium of the porolepiform Glyptolepis groenlandica. Theories on amphibian phylogeny Jarvik proposed partly controversial hypotheses about the principal structure of the vertebrate head and the