Fossil fish from northern Scotland

 Bob Davidson (UK) The north of Scotland is famous to scientists and amateur collectors for its wealth of localities where fossil fish of Devonian age can be collected. From plate tectonics, we know that in Devonian times Scotland was situated just below the equator, as part of a continent that was largely arid desert and where land plants were only just emerging. Most life on earth was still aquatic and fishes were the most successful backboned animals. The fossil fish of the area are unique in many ways. They present a window on the development of vertebrates, in which many of the innovations necessary to pave the way for the next great evolutionary step (the invasion by tetrapods of the land) were already in place. The fauna contains the acanthodians, one of the first group of vertebrates to evolve jaws, and the lobe finned fishes, so called because of their fleshy lobes supporting their pectoral and pelvic fins. The lobe fins also include the lungfish. Their fleshy fin lobes played an important role in the development of the limbs of early four-legged animals (tetrapods) and ultimately to all terrestrial vertebrates today – including ourselves. The classic Middle Devonian (380 to 375Ma old) locality is Achanarras Quarry in Caithness, where exquisitely preserved fish can be collected in an old roof tile quarry. Many such quarries existed in the past and fish have been widely collected from several localities over the years. The fish are preserved in thinly laminated siltstones and limestones, … Read More