Species-delimitation and phylogenetic analyses of some cosmopolitan species of Hypnea (Rhodophyta) reveal synonyms and misapplied names to H. cervicornis, including a new species from Brazil.
Hypnea has an intricate nomenclatural history due to a wide pantropical distribution and considerable morphological variation. Recent molecular studies have provided further clarification on the systematics of the genus; however, species of uncertain affinities remain due to flawed taxonomic identification. Detailed analyses coupled with literature review indicated a strong relationship among H. aspera, H. cervicornis, H. flexicaulis, and H. tenuis, suggesting a need for further taxonomic studies. Here, we analyzed sequences from two molecular markers (COI-5P and rbcL) and performed several DNA-based delimitation methods (mBGD, ABGD, SPN, PTP and GMYC). These molecular approaches were contrasted with morphological and phylogenetic evidence from type specimens and/or topotype collections of related species under a conservative approach. Our results demonstrate that H. aspera and H. flexicaulis represent heterotypic synonyms of H. cervicornis and indicate the existence of a misidentified Hypnea species, widely distributed on the Brazilian coast, described here as a new species: H. brasiliensis. Finally, inconsistencies observed among our results based on six different species delimitation methods evidence the need for adequate sampling and marker choice for different methods.
Programa de Pós-Graduação em Botânica, Universidade Estadual de Feira de Santana, Av. Transnordestina, s/n, Feira de Santana, Bahia, 44031-460, Brazil.|Laboratório de Algas Marinhas, Instituto de Biologia, Universidade Federal da Bahia, Rua Barão de Jeremoabo, s/n, Salvador, Bahia, 40.170-115, Brazil.
Priscila Barreto
PB
de Jesus
Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, São Paulo, São Paulo, 05508-090, Brazil.
Fabio
F
Nauer
Department of Organismic and Evolutionary Biology, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, Massachusetts, 02138, USA.
Goia de Mattos
GM
Lyra
Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, São Paulo, São Paulo, 05508-090, Brazil.
Valéria
V
Cassano
Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, São Paulo, São Paulo, 05508-090, Brazil.
Mariana Cabral
MC
Oliveira
Laboratório de Algas Marinhas, Instituto de Biologia, Universidade Federal da Bahia, Rua Barão de Jeremoabo, s/n, Salvador, Bahia, 40.170-115, Brazil.
José Marcos de Castro
JM
Nunes
Laboratório de Genética e Evolução de Plantas, Instituto de Biologia, Universidade Federal da Bahia, Rua Barão de Jeremoabo, s/n, Salvador, Bahia, 40.170-115, Brazil.
Alessandra Selbach
AS
Schnadelbach
D020418:Algal Proteins / Q000235:genetics; D001938:Brazil; D058893:DNA Barcoding, Taxonomic; D010802:Phylogeny; D000461:Rhodophyta / Q000033:anatomy & histology / Q000145:classification* / Q000235:genetics; D017422:Sequence Analysis, DNA; D013045:Species Specificity
D020418:Algal Proteins

Hypnea aspera
; 
Hypnea flexicaulis
; 
Hypnea tenuis
; Cystocloniaceae; single-marker delimitation methods; synonymy; systematics; taxonomy