“In the late 1960s, Aradio Rodaniche was diving off the coast of Nicaragua when he made the discovery that has tantalised cephalopod biologists ever since.
[…]
The discovery of an apparently social species was so implausible that few believed it and Rodaniche’s story passed into legend. He published a short account of the species in 1991, but hardly anyone had seen the animal and no one could confirm the report”
That takes account of (at least) a few decades.
I also think the issue isn’t coming up with a name but scientifically describing it. That (https://en.wikipedia.org/wiki/Species_description) can take time.
Finally, the group of people interested in having a species description may not be very large; and the group willing and able to create one even smaller. Nowadays the money in biology is in biochemistry.