One lichen is actually 126 species and counting

Well-known tropical fungal partnership could be several hundred different kinds

LICHEN RECOUNT  A tropical lichen that biologists long knew as Dictyonema glabratum turns out to be one of at least 100 different species that had been lumped together under that name, DNA studies now show. This lichen will be named as a separate Cora species.

Image courtesy of Robert Lücking

A kind of lichen that biologists thought they knew well has turned out to consist of at least 126 distinct species — and maybe more than 400 — lumped under a single name.

Dictyonema glabratum isn’t some obscure, tiny organism, says Manuela Dal-Forno of George Mason University in Fairfax, Va. The South American lichen species often grows in curly masses about the size of a fist. It can vary in color as well as in other traits, but other single species vary naturally, so biologists didn’t suspect its extreme underlying variation. Dal-Forno and her colleagues analyzed DNA in a highly variable region of the lichen’s fungal component. (Lichens combine a fungus and at least one kind of photosynthetic pal from another kingdom, but traditionally the fungus gets the name.)

At first the researchers detected 16 hidden species, a number “already considered spectacular,” says coauthor Robert Lücking of the Field Museum in Chicago. When more DNA analysis revealed over 100 species, “we were totally stunned,” he says.

A computer simulation Lücking developed estimates the total could top 400 unrecognized species, he reports with Dal-Forno and colleagues June 30 in Proceedings of the National Academy of Sciences

Susan Milius is the life sciences writer, covering organismal biology and evolution, and has a special passion for plants, fungi and invertebrates. She studied biology and English literature.

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