German to English Science Zoology Marine Biology

"Anhand des Bedeckungsgrades ist ersichtlich, dass Hydrozoen zu den dominierenden Erstbesiedlern zählen, wobei im Jahresgang zuerst die Leptozoen, dann die Anthozoen dominieren."

This term crops up repeatedly in the document in both its plural and singular forms. When I google "leptzoe," I get zero results for that word. Instead, it automatically gives me search results for protozoa. Same thing when I google my initial guess, "leptozoan(s)." But the above sentence gives the most context, and from this, I surmise that the correct translation may bew leptolinae: http://en.wikipedia.org/wiki/Leptolinae

It would be nice, however, to get confirmation from someone who really knows their marine biology. Thank you!