TWO NEW AUSTRALIAN SPECIES OFPREDAEA(NEMASTOMATACEAE, RHODOPHYTA) WITH TAXONOMIC RECOMMENDATIONS FOR AN EMENDED NEMASTOMATALES AND EXPANDED HALYMENIALES1

Publisher Website
Google Scholar
Abstract
Two new species of the red algal genusPredaeaare described from Australia. The first,Predaea auroraKraft et G.W. Saunders, sp. nov., is unusual in its cool‐temperate distribution and in a number of anatomical attributes, most notably the rhizoid‐like habit of the nutritive filaments associated with the auxiliary cells. The second species,Predaea tumescensKraft et G.W. Saunders, sp. nov., inhabits a coral reef habitat more typical of the genus but nonetheless differs in a number of anatomical details from other reported species. Nuclear small subunit rDNA sequences have confirmed the affinity ofP. aurorato other species currently included in this genus. Molecular analyses further indicate thatPredaeabelongs in the Nemastomataceae and that the Nemastomataceae and Schizymeniaceae are sister taxa in an independent clade of “lineage 4” florideophyte algae. As such, a proposal is made to resurrect the Nemastomatales Kylin emend. G.W. Saunders et Kraft to accommodate these two families. Within the Schizymeniaceae, the Australian‐endemicPlatoma australicumandPlatoma foliosumwere only distantly related to the other includedPlatoma,Schizymenia, andTitanophoraspp. We therefore proposeWetherbeellaG.W. Saunders et Kraft, gen. nov., to accommodate these two species. An additional outcome of our molecular analyses is that the genusTsengiais not a member of the Nemastomataceae (where it is currently placed) but rather forms an independent lineage in the Halymeniales that we now designate as the Tsengiaceae G.W. Saunders et Kraft, fam. nov. Finally, the South AfricanNemastoma lanceolatumJ. Agardh is transferred toTsengia.