Revision of the genus Ulvella (Ulvellaceae, Ulvophyceae) based on morphology and tufA gene sequences of species in culture, with Acrochaete and Pringsheimiella placed in synonymy

Abstract

Nielsen R., Petersen G., Seberg O., Daugbjerg N., O'Kelly C.J. and Wysor B. 2013. Revision of the genus Ulvella (Ulvellaceae, Ulvophyceae) based on morphology and tufA gene sequences of species in culture, with Acrochaete and Pringsheimiella placed in synonymy. Phycologia 52: 37–56. DOI: 10.2216/11-067.1

Microfilamentous green algae in the Ulvellaceae are notoriously difficult to identify and classify. We revised Ulvella based on the morphology of 46 unialgal culture isolates, including several from type localities, and we were guided by a phylogenetic reconstruction based on chloroplast-encoded tufA gene sequences. Species previously referred to Acrochaete, including the type species A. repens, formed a clade that included Pringsheimiella scutata and Ulvella lens, the type species of their respective genera. These species were placed in a single genus, and Ulvella had priority. The circumscription of the genus was emended to include microscopic species with branched filaments that may or may not form mono- and polystromatic disc-shaped thalli. Ten new species were described (viz. U. aequicrassa, U. dasycala, U. gigas, U. glabra, U. globocaespitosa, U. inopinata, U. pachypes, U. pseudorepens, U. vacuospora, and U. waernii), and two were resurrected (U. parasitica, previously considered a synonym of A. repens, and U. porphyrae, previously synonymised with A. viridis). Ectochaete polymorpha was placed in synonymy with U. leptochaete and Acrochaete parasitica f. zosterae with Ochlochaete hystrix. Ten new combinations were proposed for species previously referred to Acrochaete (viz. U. cingens, U. codicola, U. geniculata, U. inflata, and U. taylori) or Pringsheimiella (viz. U. gratulans, U. mauritiana, U. sanctae-luciae, U. striata, and U. udoteae).

Key Words::

• Acrochaete
• Chloroplast-encoded tufA gene sequences
• Culture studies
• Microfilamentous green algae
• Ochlochaete
• Pringsheimiella
• Ulvella
• Ulvellaceae

ACKNOWLEDGEMENTS

We thank Juan Correa for providing isolates; Peter Wagner, Copenhagen, Denmark, for the Latin diagnoses; Charlotte Hansen, Copenhagen, and Wendy Bellows, Bigelow Laboratory for Ocean Sciences, West Boothbay Harbor, Maine, USA, for assistance with the molecular work; and Peer Corfixen, Copenhagen, for technical support. A Carlsberg Foundation grant supported the molecular work and equipment. A fellowship from Japan Society for the Promotion of Science (JSPS) to R. Nielsen supported collections in Japan in 2000.

SUPPLEMENTARY DATA

Supplementary data associated with this article can be found online at http://dx.doi.org/10.2216/11-067.1.s1.