PHYLOGENY OF THE DUMONTIACEAE (GIGARTINALES, RHODOPHYTA) AND ASSOCIATED FAMILIES BASED ON SSU rDNA AND INTERNAL TRANSCRIBED SPACER SEQUENCE DATA

• Published in: Journal of Phycology
• Main Authors: Tai, Vera, Lindstrom, Sandra C., Saunders, Gary W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2001
• Subjects: Antarctic; Pacific; The Antarctic; Antarc*
• Online Access: http://dx.doi.org/10.1046/j.1529-8817.2001.037001184.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1529-8817.2001.037001184.x; https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1529-8817.2001.037001184.x

Small subunit (SSU) rDNA was sequenced for 25 species in 19 genera of the Gigartinales (Rhodophyta). As well, the internal transcribed spacer (ITS) region was sequenced, and a data matrix of 36 morphological characters was constructed for 16 species of Dumontiaceae. Phylogenetic trees were calculated from a multiple alignment of the SSU sequence data to infer relationships between species of Dumontiaceae and other gigartinalean taxa. The SSU analysis produced a polyphyletic Dumontiaceae. Notably, Acrosymphyton failed to associate with the included Gigartinales, let alone the Dumontiaceae, supporting an earlier proposal to remove it to a new family. The analyses were equivocal about the phylogenetic affinities of Dudresnaya , which clustered with the Kallymeniaceae, and the affinities of the Indo‐West Pacific Gibsmithia , Kraftia , and Dasyphloea , the last‐mentioned clustering with the Antarctic Gainiaceae, and these four taxa with Portieria (Rhizophyllidaceae). Further investigations are necessary to resolve relationships among these taxa. Rhodopeltis , a genus recently moved to the Dumontiaceae from the Polyideaceae, showed a weak association with the remaining northern Dumontiaceae. The final group consisted of cold‐temperate Northern Hemisphere species. Phylogenetic analyses using a combination of SSU, ITS, and morphological data within this clade produced two strongly supported clades, a Dilsea / Neodilsea clade and a Cryptosiphonia / Dumontia clade. Dilsea is derived from a paraphyletic Neodilsea and may itself be polyphyletic. Atlantic and Pacific isolates of Dumontia contorta clearly showed sufficient divergence to warrant recognition as distinct species, and Dumontia alaskana , sp. nov. is proposed for the Pacific species.