Pinnatiphycus menouana gen. et sp nov (Rhodophyta : Dicranemataceae) from New Caledonia and Fiji (South Pacific): vegetative and reproductive morphology and molecular phylogeny

2006

Article référencé dans le Web of Science WOS:000239049400004

N'Yeurt Antoine, Payri Claude, Gabrielson P. W., Fredericq S.

Phycologia, 2006, 45 (4), p. 422-431 ISSN 0031-8884

A new tropical genus and species belonging to the family Dicranemataceae, Pinnatiphycus menouana, is described from lagoon and outer reef-slope habitats in New Caledonia and Fiji. The new genus differs from other members of the family by the unique combination of the following characters: (1) tetrasporangia borne in terminal nemathecia on lateral cylindrical branchlets; and (2) the disposition of cystocarps along lateral branchlets rather than on the main axis itself. The new species differs from Peltasta australis J. Agardh by the presence of cylindrical lateral branchlets along the flattened main axes and the occurrence of reproductive structures in terminal, subterminal or basal positions on the lateral branchlets. It differs from subtropical Reptataxis rhizophora (Lucas) Kraft from Lord Howe Island by the presence of both yellowish refractive medullary cell clusters and cylindrical lateral branches bearing subapical tetrasporangial sori and cystocarps, as well as a central fusion cell and the production of carposporangia in chains of two to three rather than four to six. rbcL molecular analysis of Fijian samples unequivocally places the genus in the family Dicranemataceae with 100% bootstrap support, strongly relating it to two species of Tylotus. The family itself, however, received only weak bootstrap support (66%) for distinguishing it from the clade containing the virtually Australian-endemic families Mychodeaceae and Acrotylaceae. Pinnatiphycus favors deepwater habitats (65-70 m) with low light intensities or shallower (< 30 m) but turbid high-current areas, which may have contributed to it being overlooked in the past.

PAR00001030