John Albert Long (born 1957) is an Australian paleontologist who is currently Strategic Professor in Palaeontology at Flinders University in Adelaide, South Australia. He was previously the Vice President of Research and Collections at the Natural History Museum of Los Angeles County. He is also an author of popular science books. His main area of research is on the fossil fish of the Late Devonian Gogo Formation from northern Western Australia. It has yielded many important insights into fish evolution, such as Gogonasus and Materpiscis, the later specimen being crucial to our understanding of the origins of vertebrate reproduction. His love of fossil collecting began at age 7 and he graduated with PhD from Monash University in 1984, specialising in Palaeozoic fish evolution. He held postdoctoral positions at the Australian National University (1984–85, Rothmans Fellow), The University of Western Australia (1986–87, Queen Elizabeth II Award) and The University of Tasmania (1988–89, ARC Fellow) before taking up a position as Curator in Vertebrate Palaeontology at the Western Australian Museum (1989–2004), and then as Head of Sciences at Museum Victoria (2004–2009).
Long's paleontological research has involved field work collecting and studying Palaeozoic fishes throughout Australia, Antarctica, South Africa, Iran, Vietnam, Thailand and China. Long's early research led to the refinement of a new biostratigraphic scheme for dating Palaeozoic sequences in Victoria, Australia. Most of his later research has focussed on collecting and describing the well-preserved 3-dimensional Devonian fishes from the Gogo Formation, Western Australia. His major discoveries from his field expeditions to the Gogo fossil sites (1986–2008) included the first complete skull of an osteolepiform fish, Gogonasus, and a new specimen showing that Gogonasus had large spiracles opening on top of its head. Other discoveries include several new types of dipnoans and arthrodires, and the discovery of the first Devonian fishes showing embryos inside them. This later discovery, published in the journal Nature (May 2008) was the first time that reproduction by internal fertilisation was demonstrated in the extinct Class Placodermi, and the oldest evidence for vertebrate viviparity yet discovered. One of the specimens, named Materpiscis, was also the only known fossil to show a mineralised umbilical structure linked to the unborn embryo. Nature magazine made a short documentary video about this discovery. Other Gogo fish fossils have been found showing remarkable preservation of 3-D muscle tissues, nerve cells and microcapillaries, making this one of the world's most extraordinary sites for exceptional preservation of fossils of this age. One of Long's discoveries, the placoderm Mcnamaraspis, made history by becoming Australia's first official state fossil emblem when it was declared by the Governor as the Western Australian fossil emblem on 5 December 1995.