A strange, armored, jawless fish with a big heart upsets paleontologists

An approximately 400-million-year-old fossil, Norselaspis glacialis, exhumed from sediments collected in Spitsbergen in 1969 and rediscovered in a museum's storerooms, reveals an unexpected internal anatomy. Using X-rays from the Paul Scherrer Institute, Pierre Gueriau's team has reconstructed the brain, inner ear, high-set and highly mobile eyes, as well as a surprisingly large heart.