The first four legged animal known to humans was the Acanthostega, which had eight toes to each foot of it’s four feet!
It would use its toes to grip the plants in the water as it swam, although the Acanthostega spent the majority of its time in the water not on land.
The now extinct Acanthostega was among the first vertebrate animals to have recognizable limbs and was considered to not be suited to come onto land – which is why it spent most of its life underwater.