Description
About Palaeospondylus gunni Scottish Devonian
Physical Description
Palaeospondylus gunni is a small fish ranging in size from approximately 8mm to 50mm. The body shows no sign of scales, but the internal skeleton is well preserved. Some specimens can show a body outline and/or small bony triangles on the side of the fossil. The name Palaeospondylus means “ancient vertebrate”.
Age and Distribution
Palaeospondylus is from the Middle Devonian of Scotland. This fish lived approximately 385 million years ago. At the time this area of Scotland was part of the Orcadian Basin, which was a huge complex of lakes that stretched for hundreds of miles. During this period plants started to rapidly colonize the land and fishes dominated nearly every niche of seas and lakes, hence why this period is also known as the “Age of Fishes”. Palaeospondylus gunni co-inhabited the lake with other fishes like the acanthodians Mesacanthus, Cheiracanthus and Diplacanthus, the osteolepids Gyroptychius and Osteolepis, the lungfish Dipterus, the porolepid Glyptolepis, the euphanaropid Euphanrops and the placoderms Coccosteus, Pterichtyodes, Rhamphodopsis and Homostius.
About Palaeospondylus gunni Scottish Devonian
Evolutionary Significance
Almost 130 years after its discovery the verdict is still out as to what Palaeospondylus is related to. It is thusly enigmatic that since the 1890’s workers have assigned it to nearly every group of early vertebrate, jawed and jawless, including; a type of hagfish, a larval lungfish, a larval tetrapod, an arthodire, an unarmoured placoderm, a holocephalan or other chrondrichthyan, to name a few. Its skeleton is so uniquely formed that finding homologies (=shared traits) with other groups of fishes is difficult and always controversial. As there is still no definitive solution to this day, Palaeospondylus gunni remains by far the most enigmatic fossil in the history of early vertebrate palaeontology.
Taxonomy
Palaeospondylus gunni belongs to the ? family of Palaeospondylidae. With the P.gunni being the sole member.
