Meridionella gen. nov., a new genus of Cystocloniaceae (Gigartinales, Rhodophyta) from the Southern hemisphere, including M. obtusangula comb. nov. and M. antarctica sp. nov

TONICELLI, GINA; CROCE, M. EMILIA; DIAZ-TAPIA, PILAR; FREDERICQ, SUZANNE; FRESHWATER, DAVID; GAUNA, M. CECILIA; PARODI, ELISA.R; VERBRUGGEN, HEROEN ; HOMMERSAN, MAX

JOURNAL OF PHYCOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2021 vol. 57 p. 797 - 816

0022-3646

The classification of Cystoclonium obtusangulum has been questioned since the species was first described by Hooker and Harvey as Gracilaria obtusangula. The objective of this study was to provide the first comprehensive taxonomic analysis of Cystoclonium obtusangulum, based on rbcL and 18S rRNA gene sequences coupled with morphological observations made on syntype specimens and new collections. Sequence divergences of rbcL and maximum-likelihood phylogenies for both rbcL and 18S demonstrated that specimens identified as Cystoclonium obtusangulum represent a clade of two distinct species that is distantly related to the generitype Cystoclonium purpureum. A new genus, Meridionella gen. nov. is proposed for this clade. The two species placed in this new genus were morphologically indistinguishable cryptic species, but have disjunct distributions, with Meridionella obtusangula comb. nov. found from temperate to cold coasts of South America and the Falkland Islands and Meridionella antarctica sp. nov., occuring in Antarctic waters. Vegetative and reproductive characters of Meridionella gen. nov. are described, and implications of our results for the biogeography of the family Cystocloniaceae are discussed.