Mesacanthus is an ancient and extinct genus of Acathodian (Spined) fish. It inhabited the waters of the Iapetus Sea (about what is now Scotland) during the Devonian period. The fish were small (approximately 30 mm when fully grown), but possessed a number of sharp spines, accompanied by a unique tail fin, which is thought to have extended to a sharp point. It was first discovered in 1888 and has since been used as an important component of the British fossil record, as one of the first complex marine vertebrate fish. This specimen was once part of an old fossil collection and has been salvaged to be re-homed as part of a new one – this might be an addition to any extensive British fossil hoards or the beginning of a new marine-centric compilation. Provided in appropriate packaging with an information label and schematic reconstruction. This specimen weighs roughly 938 grams and measures approximately 30 x 12 x 2 cm.