Predaea feldmannii subsp. azorica (Nemastomataceae, Nemastomatales), a new subspecies of red algae (Rhodophyta) from the Azores

The red algal genus Predaea (Rhodophyta, Nemastomataceae, Nemastomatales) currently comprises 20 species found in tropical to temperate waters worldwide. The species going under the name Predaea feldmannii (Nemastomataceae, Nemastomatales) in the Azores is here reduced to subspecies rank as P. feldmannii subsp. azorica on the basis of comparative morphology and rbcL sequence analysis. The evidence presented here includes a phylogenetic tree inferred from chloroplast-encoded rbcL sequences of selected members of the Nemastomatales. P. feldmannii subsp. azorica shares with P. feldmannii subsp. feldmannii linear-oblong outer cortical cells, dichotomously branched cortical fascicles, a large number of auxiliary nutritive cells per cluster, and gonimoblast initiation from the incoming connecting filament near its point of fusion with the auxiliary cell. Differences include a sac-like, lobed thallus and occasional lateral cells on the carpogonial branch in the Azorean subspecies, versus a subcylindrical, subdichotomous habit with marginal lobes, and lack of lateral cells on the carpogonial branch in P. feldmannii subsp. feldmannii. The known distribution of P. feldmannii subsp. feldmannii is worldwide in tropical regions and so far P. feldmannii subsp. azorica is known only from the Azores.