DNA barcoding reveals multiple overlooked Australian species of the red algal order Rhodymeniales (Florideophyceae), with resurrection of Halopeltis J. Agardh and description of Pseudohalopeltis gen. nov.

Abstract

The DNA barcode (COI-5P) was used to investigate cryptic diversity among Rhodymenia spp. in southern Australia. Whereas eight species are currently recognized, we uncovered ca. 20 genetic species groups, phylogenetically assigned to four genera in two families. Procumbent specimens with molecular and anatomical signatures of the Fryeellaceae are assigned to Pseudohalopeltis tasmanensis gen. et sp. nov. Collections from Lord Howe Island recorded in the field as Rhodymenia / Fauchea sp. are assigned to the poorly known genus Microphyllum as Microphyllum robustum sp. nov. A cluster of species with distinct molecular and anatomical attributes is included in a resurrected Halopeltis J.G. Agardh, including Halopeltis australis (J. Agardh) comb. nov. (type species); Halopeltis austrina (Womersley) comb. nov.; Halopeltis cuneata (Harvey) comb. nov. [including Rhodymenia halymenioides (J. Agardh) Womersley]; Halopeltis gracilis sp. nov.; Halopeltis prostrata sp. nov.; and Halopeltis verrucosa (Womersley) comb. nov. Four additional species of Halopeltis from Lord Howe Island (LH1, LH2), Tasmania (TAS), and Western Australia are not characterized further. For Rhodymenia sensu stricto, similar levels of cryptic diversity were noted. Samples tentatively field-identified as “ Rhodymenia sonderi ,” but having affiliations to Rhodymenia rather than Halopeltis, are referred to Rhodymenia novahollandica sp. nov. Collections field-identified as R. obtusa are genetically distinct from that species and are assigned to Rhodymenia wilsonis (Sonder) comb. nov. Two highly divergent species currently identified as Rhodymenia leptophylla (LH from Lord Howe Island; TAS from Tasmania), as well as two additional cryptic previously unnamed taxa from South Australia (SA) and Victoria (VIC), are not characterized further.

First report of Halopeltis (Rhodophyta, Rhodymeniaceae) from the non-tropical Northern Hemisphere: H. adnata (Okamura) comb. nov. from Korea, and H. pellucida sp. nov. and H. willisii sp. nov. from the North Atlantic

“…All PCR products were sequenced using a Big Dye Terminator Cycle Sequencing Ready Retional collections and genetic material to clarify species relationships (e.g., McDonald 2010, Kraft andSaunders 2011). Using mitochondrial barcoding techniques and large subunit ribosomal RNA (LSU) gene sequences, a recent paper by Saunders and McDonald (2010) resurrected the genus Halopeltis J. Agardh (1854), for the last 150 years an entity subsumed in Rhodymenia Greville (1830).…”

“…Subsequent 19th century phycologists made no mention of Halopeltis. The convoluted nomenclatural history of this genus is recounted in detail by Saunders and McDonald (2010), who, after resurrecting Halopeltis from synonomy, moved three additional Rhodymenia and Rhodymeniocolax Setch. (1923) species to the genus and described two novel species that they had collected in southeastern Australia and Lord Howe Island.…”

“…To explore further the phylogenetic affinities of the newly discovered COI-5P genetic species, LSU and rbcL data were generated for one representative each of these three newly uncovered genetic species, as well as for additional rhodymeniaceous species (Table 1); emphasizing the Halichrysis and Halopeltis lineage with suitable outgroups (Saunders and McDonald 2010), to allow for single (COI-5P, LSU, and rbcL), as well as a combined gene analyses (Fig. 1).…”

“…These studies have discovered cryptic diversity within the order (e.g., Saunders et al 2006, Ballantine and LozadaTroche 2008, Schneider and Lane 2008, Saunders and McDonald 2010, as well as allowing for generic discovery and realignment in the Rhodymeniaceae, Fryeellaceae, Faucheaceae, Hymenocladiaceae, Champiaceae and Lomentariaceae (e.g., Millar et al 1996, Saunders et al 1999, 2006, Wilkes et al 2005, Dalen and Saunders 2007, Le Gall et al 2008, Saunders and McDonald 2010, Suzuki et al 2010. Combined, such molecular-assisted, alpha taxonomic (MAAT) studies have begun to demonstrate a significantly clearer picture of species richness and evolutionary relationships within this order than was known in the 20th century (Bliding 1928, Kylin 1931, 1956, Sparling 1957.…”

Diversidade de Gelidiales (Rhodophyta) baseada em marcadores moleculares e estudos morfoanatômicos para região Sudeste do Brasil

“…Uma das ferramentas moleculares que auxilia a taxonomia é a técnica de "DNA barcoding", que consiste em obter um fragmento relativamente curto de DNA (~400-700 pb), que pode ser inteiramente sequenciado como o mesmo par de "primers" utilizado na PCR, e ser utilizado em uma comparação com um banco de dados para identificar a espécie. Este sistema começou a ser utilizado principalmente em animais (Hebert et al, 2003), mas esse estudo tem aumentado cada vez mais em algas (Clarkston & Saunders, 2010;Costa et al, 2012;Le Gall & Saunders, 2010;Milstein & Saunders, 2012;Milstein et al, 2011;Saunders & McDonald, 2010;Saunders, 2005;Sherwood & Presting, 2007;Sherwood et al, 2008).…”