Reassignment of some South African species to <i>Chamberlainium</i>, with a comment about the recognition of families of Corallinales (Rhodophyta)

Abstract

Using an integrated taxonomic approach, DNA sequencing of field-collected and historical type specimens, as well as morpho-anatomical characters and species’ ecology and biogeography, we reassessed the single-most ecologically important non-geniculate coralline algal genus, Spongites, in South Africa. DNA sequences (psbA, rbcL) from type and recently collected specimens formed well-supported clades within Chamberlainoideae, all aligning closer to the generitype of Chamberlainium, C. tumidum, than to the generitype of Spongites, S. fruticulosus (Neogoniolithoideae, Corallinales). Nine species of Chamberlainoideae are now confirmed for South Africa, eight in Chamberlainium and one in Pneophyllum. South African specimens called Spongites discoideus and S. yendoi, both with type localities far removed from South Africa, Argentina and Japan, respectively, are not those species. The latter species had included seven cryptic to pseudocryptic species. We describe the most ecologically important of these species, Chamberlainium cochleare sp. nov., as well as resurrect Lithophyllum natalense, and transfer both it and Spongites impar to Chamberlainium. Additionally, we argue that within the monophyletic Corallinales it is premature to elevate subfamilies to families when several subfamilies have no distinguishing morpho-anatomical characters. Furthermore, some morpho-anatomical characters that have been proposed to distinguish subfamilies vary even within a single subfamily.

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