title: Delimitating cryptic species in the Gracilaria domingensis complex (Gracilariaceae, Rhodophyta) using molecular and morphological data.
abstract: Species in the genus Gracilaria that display conspicuously flattened vegetative morphologies are a taxonomically challenging group of marine benthic red algae. This is a result of their species richness, morphological similarity, and broad phenotypic plasticity. Within this group, the Gracilaria domingensis complex is one of the most common, conspicuous, and morphologically variable species along the tropical western Atlantic Ocean. Previous research has identified that members of this complex belong to two distantly related clades. However, despite this increased phylogentic resolution, species delimitations within each of these clades remain unclear. Our study assessed the species diversity within this difficult complex using morphological and molecular data from three genetic markers (cox1, UPA, and rbcL). We additionally applied six single-marker species delimitation methods (SDM: ABGD, GMYCs, GMYCm, SPN, bPTP, and PTP) to rbcL, which were largely in agreement regarding species delimitation. These results, combined with our analysis of morphology, indicate that the G. domingensis complex includes seven distinct species, each of which are not all most closely related: G. cervicornis; a ressurected G. ferox; G. apiculata subsp. apiculata; a new species, Gracilaria baiana sp. nov.; G. intermedia subsp. intermedia; G. venezuelensis; and G. domingensis sensu stricto, which includes the later heterotypic synonym, G. yoneshigueana. Our study demonstrates the value of multipronged strategies, including the use of both molecular and morphological approaches, to decipher cryptic species of red algae.
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, Massachusetts, 02138, USA.|Programa de Pós-Graduação em Botânica, Universidade Estadual de Feira de Santana, Av. Transnordestina, s/n, Feira de Santana, Bahia, 44031-460, Brazil.
authors.forename: Goia de M
authors.initials: GM
authors.lastname: Lyra
authors.affiliation: The Environment Institute, Australian Centre for Evolutionary Biology and Biodiversity, School of Earth and Environmental Sciences, University of Adelaide, DX 650-418, Adelaide, South Australia, 5005, Australia.|Department of Environment, Water and Natural Resources, State Herbarium of South Austrália, PO Box 2732, Kent Town, South Australia, 5071, Austrália.|Departamento de Botânica, CCB, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, 88040-900, Brazil.|Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, São Paulo, São Paulo, 05508-090, Brazil.
authors.forename: C Frederico D
authors.initials: CF
authors.lastname: Gurgel
authors.affiliation: Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, São Paulo, São Paulo, 05508-090, Brazil.
authors.forename: Emmanuelle da S
authors.initials: ED
authors.lastname: Costa
authors.affiliation: Programa de Pós-Graduação em Botânica, Universidade Estadual de Feira de Santana, Av. Transnordestina, s/n, Feira de Santana, Bahia, 44031-460, Brazil.
authors.forename: Priscila B
authors.initials: PB
authors.lastname: de Jesus
authors.affiliation: Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, São Paulo, São Paulo, 05508-090, Brazil.
authors.forename: Mariana C
authors.initials: MC
authors.lastname: Oliveira
authors.affiliation: Instituto de Biociências, Universidade de São Paulo, Rua do Matão 277, São Paulo, São Paulo, 05508-090, Brazil.
authors.forename: Eurico C
authors.initials: EC
authors.lastname: Oliveira
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, Massachusetts, 02138, USA.
authors.forename: Charles C
authors.initials: CC
authors.lastname: Davis
authors.affiliation: Laboratório de Algas Marinhas, Instituto de Biologia, Universidade Federal da Bahia, Rua Barão de Jeremoabo, s/n, Salvador, Bahia, 40170-115, Brazil.
authors.forename: José Marcos de Castro
authors.initials: JM
authors.lastname: Nunes
mesh_terms: D020418:Algal Proteins / Q000235:genetics; D017691:Caribbean Region; D048028:DNA, Algal / Q000235:genetics; D044724:Gracilaria / Q000145:classification* / Q000166:cytology / Q000235:genetics; D009656:North America; D010802:Phylogeny; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D012624:Seaweed / Q000145:classification* / Q000166:cytology / Q000235:genetics; D017422:Sequence Analysis, DNA; D013020:South America; D013045:Species Specificity
chemical_list: D020418:Algal Proteins; D048028:DNA, Algal; D012338:RNA, Ribosomal, 23S
keywords: 
  Gracilaria
  ; Gracilariales; Rhodophyta; rbcL; systematics; taxonomy