We all know that limbs improved for locomotor-efficiency, but how did they actually evolve? Researchers have long established the fact that early limb-evolution started at the late Cambrian period, moving forward until specialized pentadactyle limbs appear in the Tertiary.
Though the link between the fish-fins and the evolution of limbs has been well-established, the undergone process has stayed clouded, until recently, a 400 million-year-old fossilized fin from a strange-looking, primitive fish has been discovered.
It eventually is shedding light on how fins evolved into limbs, enabling animals to walk on land. The fossilized fin discovered is from a type of lobe-finned fish — ‘coelacanth.’
Being the only skeletal fin remains from the extinct relatives of today’s living coelacanths found till date, the four-inch-long specimen is significant in furthering the study on the fin evolution process.
Predicted from the size of the newfound fin, the fish dubbed — Shoshinia arctopteryx — would have been about 18 to 24 inches in length, when alive. Named after the Shoshine people and the Shoshone National Forest, the fish was spotted in Beartooth Butte in northern Wyoming.
This new discovery has crumbled the long-time assumption that the living coelacanths and their lungfish relatives are the accurate models of their ancestors that swam the waters hundreds of millions of years ago – and has opened new horizons into researching the ‘evolution of limbs’.