Wow, that's a lot of coeruleus!
On the other hand, we have:

Bungarus caeruleus (a snake)
Litoria caerulea (a frog)
Cyprinella caerulea (a fish)
Labidochromis caeruleus (a fish)
Ethiostoma caerulea (a fish)
Timalus caeruleus (a moth)
Plexippus caeruleus (a spider)
Cyanocorax caeruleus (a bird)
Elanus caeruleus (a bird)
Parus caeruleus (a bird)
Hygrophorus caeruleus (a mushroom)
Couchioplanes caeruleus (a bacterium)
Oxypetalum, Xiphidium, Allium, Conospermum, Polemonium, Calochilus, and
Gladiolus caeruleum (flowering plants)

Which brings me back to my original question, which really wasn't all that
important :-)  What is the difference between caeruleus and coeruleus?
Actually I think a previous post on the subject may have provided a clue.
Someone yesterday mentioned, I believe, that coeruleus is from new Latin.
So I suspect it is probably a derivative of the classical Latin caeruleus.

New Question!  Are there any mollusks named after Linnaeus?  Or any animal
species at all??  If not, why not?  It would seem appropriate that someone
would have seen fit to honor the man who started it all!   Well okay, he
didn't "start it all", but his adaptation of binomial nomenclature is still
the foundation of modern taxonomy.

Paul M.