RESUMEN
The Peyssonneliaceae represents the only family in the order Peyssonneliales, a clade of red encrusting algae distributed worldwide, including 136 species in eleven currently accepted genera. Delineation of genera in the Peyssonneliaceae has mostly been based on vegetative characteristics. Previous molecular phylogenies have shown that some traditionally circumscribed genera are not monophyletic and relationships among them are uncertain. We contribute to the knowledge of the evolutionary history of this clade, presenting a robust rbcL phylogeny that provides new insights on the origin and diversification of the Peyssonneliales. Based on a broad dataset and morphological analyses, we propose a revised taxonomic scheme for the Peyssonneliales resolved as monophyletic with well-supported main lineages. Our results show that Peyssonnelia is polyphyletic, and, therefore, we propose three new genera, Agissea, Olokunia, and Rhodowynnea to accommodate species currently assigned to Peyssonnelia, but distantly related to the clade with the type species of the genus. Additionally, barcoding techniques and analyzed criteria for specific delimitation supported the establishment of one new genus, Brasilophycus, and seven new species, from northeastern Brazil: Agissea amadoi, A. densissima, A. taberniforma, A. villatlantica, A. yemonjasagbae, Brasilophycus similis, and B. roseomarginatus. Our integrative taxonomic approach reveals underestimated diversity of Brazilian Peyssonneliales. Investment in broader sampling along the Brazilian coast and other tropical areas may reveal that its marine biodiversity can be expanded, enlightening our knowledge about this ecologically important group of red algae.
Asunto(s)
Rhodophyta , Biodiversidad , Evolución Biológica , Brasil , Filogenia , Rhodophyta/genéticaRESUMEN
The Southwest Atlantic is notable for having extensive reef areas cemented by nongeniculate coralline red algae. Based on an analysis of four genetic markers and morpho-anatomical features, we clarify the species of Harveylithon in the tropical and warm temperate Southwest Atlantic. Species delimitation methods (mBGD, ABGD, SPN, and PTP), using three markers (psbA, rbcL, and COI), support the recognition of three new species: H. catarinense sp. nov., H. maris-bahiensis sp. nov., and H. riosmenum sp. nov., previously incorrectly called Hydrolithon samoënse. Our findings highlight the importance of using an approach with several lines of evidence to solve the taxonomic status of the cryptic species.
Asunto(s)
Rhodophyta , Brasil , FilogeniaRESUMEN
Absorption spectra are indicative of biological sample chemical composition and can be used as a basis for the construction of descriptive and predictive models for biotechnological screening or assays. In marine algae, chemical composition can vary due to species-specific differences in biochemistry, as well as intra-specific responses to unique environmental variables. Different indices (UVCi, UVB+Ai and PARi) were proposed and calculated to evaluate how photoprotective compounds vary in 18 species of Phaeophyceae. In addition, they were correlated to abiotic factors. Through this technique, seven main peaks were detected in the absorbing spectra of marine brown algal extracts. The highest photoprotective indices values were found in species collected in tropical areas, where higher solar radiation is observed compared to the southern Brazilian coast. Considering additional abiotic factors, water temperature and nitrate concentration were negatively correlated with UV indices. PARi's indices were positively affected by nitrate. All species collected on the Brazilian coast have absorption peaks in the region of phenolic compounds and carotenoids, suggesting that tropical marine brown macroalgae may have developed an effective antioxidant defense system, suggesting adaptation to environments characterized by high solar radiation. UVR/PAR indices congregated essential information to possible future biotechnological screening, facilitating selection of high priority species or sites, fostering actions to enhance alternative sustainable management strategies of coastal environments.
Asunto(s)
Absorción de Radiación , Phaeophyceae/química , Protectores contra Radiación/química , Algas Marinas/química , Rayos Ultravioleta , BrasilRESUMEN
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.
Asunto(s)
Gracilaria/clasificación , Algas Marinas/clasificación , Proteínas Algáceas/genética , Región del Caribe , ADN de Algas/genética , Gracilaria/citología , Gracilaria/genética , América del Norte , Filogenia , ARN Ribosómico 23S/genética , Algas Marinas/citología , Algas Marinas/genética , Análisis de Secuencia de ADN , América del Sur , Especificidad de la EspecieRESUMEN
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.
Asunto(s)
Filogenia , Rhodophyta/clasificación , Proteínas Algáceas/genética , Brasil , Código de Barras del ADN Taxonómico , Rhodophyta/anatomía & histología , Rhodophyta/genética , Análisis de Secuencia de ADN , Especificidad de la EspecieRESUMEN
Sete táxons de rodofíceas marinhas bentônicas são referidos pela primeira vez para o litoral brasileiro: Acrochaetium corymbiferum (Thur. in Le Jolis) Batters, A. liagorae Brgesen, Aglaothamnion herveyi (M. Howe) Aponte, D.L. Ballant. & J.N. Norris, Crouanophycus latiaxis (L.A. Abbott) Athanas., Grallatoria reptans M. Howe e Gelidiella sanctarum Feldmann & Hamel. Gelidiopsis repens (Kütz.) Weber Bosse é pela primeira vez referido para o Oceano Atlântico. As coletas foram realizadas no medio e infralitoral. O material está depositado no Herbário Alexandre Leal Costa. Referência da descrição original, basiônimo, descrição morfológica, distribuição geográfica e comentários taxonômicos são apresentados para cada táxon estudado.
Seven taxa of benthic marine rodophytes are reported for the first time from the Brazil littoral: Acrochaetium corymbiferum (Thur. in Le Jolis) Batters, A. liagorae Brgesen, Aglaothamnion herveyi (M. Howe) Aponte, D.L. Ballant. & J.N. Norris, Crouanophycus latiaxis (L.A. Abbott) Athanas., Grallatoria reptans M. Howe and Gelidiella sanctarum Feldmann & Hamel. Gelidiopsis repens (Kütz.) Weber Bosse this is the new reference to the Atlantic Ocean. The material collected on mediolittoral and infralittoral was deposited in the Herbarium Alexandre Leal Costa (ALCB) at the Universidade Federal da Bahia. Reference to the original description, basionym, morphological description, geographical distribution and taxonomical comments are presented for each taxon studied.