Solenopora

The extinct Solenoporaceae have traditionally been interpreted as a group of red algae ancestral to the Corallinales.
The genus from which they take their name, Solenopora, originates in the Ordovician. Unlike the Corallinaceae, this family has large vegetative cells and an undifferentiated thallus.
Additionally there are external, non-calcified sporangia.
The differences in structure suggest that the holotype is not an alga at all, but rather is a chaetetid sponge. Post-Palaeozoic specimens therefore require re-classification. However, some algal taxa are still classified within the genus.
Some specimens of algal "Solenopora" retain an original pink colouration, which is banded with growth stages of the fossil; this is produced by boron-containing hydrocarbons.
The solenoporaceae mineralized with calcite.
Other genera within the Solenoporaceae.
Although the following other genera have been included in this family, their status is uncertain due to the loose definition of the family.