Viridis and felodon: shared worldbuilding?

A recent question in the "Hal Clement challenge" asked if there was any meaning or significance to the name "felodon", an amphibian carnivore with large fangs that featured in Clement’s novella of 1963, The Green World. Some years earlier in 1956, Margaret St. Clair wrote The Green Queen, available at the Internet Archive under a slightly different name. It too was set on a green planet (like Clement’s world it was called "Viridis" from the Latin word for green), and also involved an unpleasant fanged predator called a felodon.

Given these similarities, I wondered if Clement had taken the idea of the green planet, and the felodon, from St Clair. However, I have noticed that "The Golden Helix", a 1954 short story by Theodore Sturgeon, is also set on a green planet called Viridis, and involves "a scaly carnivore with [the] catlike tusks" called a felodon.

This seems beyond a coincidence. Does anyone know if these authors consciously borrowed these plot elements from each other? Were they in discussion with each other?