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Single-stranded conformational polymorphism (SSCP) analysis of Rubisco spacer plastid haplotypes was used to assess population differentiation in the mangrove-dwelling red alga Caloglossa leprieurii (Montagne) J. Agardh. Over 1000 samples from 16 populations in northern and eastern Australia were scored with SSCP. Seven haplotypes were discovered, three of which were only found in single populations. The haplotypes formed three phylogenetically distinct lineages. A haplotype found only in north Australia (haplotype N) has closer affinities with a haplotype previously found in Japan than with any other Australian haplotypes. One haplotype (B) was dominant in northern populations and another (C) was dominant in southern populations. Haplotype A was found in geographically intermediate populations but never in high abundance ( 10 %). Population analysis of haplotype frequencies revealed that many populations were significantly differentiated from each other. These data indicate that populations of C. leprieurii in Australia are genetically isolated from each other, as many individual populations, probably due to limited gene flow.

The trend in naming genera based almost exclusively on molecular data, and not on morphological diagnostic characters, is increasing. In bifurcating phylogenetic trees generic cut-offs are arbitrary, but at the bare minimum nomenclatural changes should be supported by multiple phylogenetic methodologies using appropriate models for all the various gene partitions, strong support with all branch support methods, and should also result in adding to our knowledge of the interrelationships of taxa. We believe that a recent taxonomic treatment of the genus Pyropia (Yang et al. 2020) into several genera is unwarranted. We reanalysed the data presented in the recent article, using additional phylogenetic methods. Our results show that many of the newly established genera are not well supported by all methods, and the new circumscription of the genus Pyropia renders it unsupported. We also tested additional outgroups, which were previously suggested as sister to Pyropia, but this did not substantially change our conclusions. These generic nomenclatural changes of the previously strongly supported genus Pyropia, do not shed light on the evolution of this group and have serious consequences in these commercially important algae, that are also governed by a plethora of regulation and by-laws that now need to be amended. We suggest that the over-splitting of groups based only on poorly produced and modestly supported phylogenies should not be accepted and that the genus Pyropia sensu Sutherland et al. (2011) be restored.

Koliellopsis inundata Lokhorst gen. & sp. nov. (Trebouxiophyceae) is described from periodically flooded agricultural fields in the borderland of Belgium and the Netherlands. This new, unbranched, filamentous alga is typified by relatively long vegetative cells, which have a bilobed, laminate chloroplast with a nucleus positioned in its median constriction. Its filaments lack a distinct basal-distal differentiation and both ends terminate in about equally shaped, rounded or, more often (slightly) tapering cells. Despite its semiterrestrial occurrence the new alga does not attach to hard substrate, presumably owing to the lack of end cells to produce mucilage and to function as a holdfast. The systematic position of Koliellopsis among the green algae is inferred from ultrastructural examinations of the cell division patterns and from phylogenetic analyses of partial 18S rRNA gene sequences.