Lobe-finned fish fossil

The distinctive, smooth, grey rocks on Westray’s exposed sea cliffs and shelving shore host fossils of fish which died 390 million years ago.

Here’s one, called Osteolepis panderi.

Osteolepis is from the Greek ostéon, which means ‘bone’ and lepis which means ‘scale’. It was a fish with bony scales. I’m grateful to David Leather for identifying it for me. Here’s what he said:

I can see exactly what it is: the zone fossil, Osteolepis panderi, for the Lower Rousay Flagstone, about 390 million years old/ago. The post parietal plate is clearly seen, top left. Brings to mind the wonderful excursions we’ve had all over the island. Brilliant.

The ‘postparietal plate’ is the bone on the top of the head. Osteolepis was a lobe-finned fish, a fish with very strong muscular lobes which allowed it to move on the muddy surface, and push itself from pool to pool, as Lake Orcadie dried up from season to season. Its relatives would eventually have four strong limbs and become the ancestors of all four-legged vertebrates.

Looking into the past allows us to see their future.