Dictyota chalchicueyecanensis sp. nov. (Dictyotales, Phaeophyceae) en el Golfo de México: evidencias moleculares y morfológicas
Dictyota chalchicueyecanensissp. nov. (Dictyotales, Phaeophyceae) in the Gulf of Mexico: molecular and morphological evidence
Dictyota chalchicueyecanensis sp. nov. (Dictyotales, Phaeophyceae) en el Golfo de México: evidencias moleculares y morfológicas
Dictyota chalchicueyecanensissp. nov. (Dictyotales, Phaeophyceae) in the Gulf of Mexico: molecular and morphological evidence
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Date
2016
Authors
Francisco F. Pedroche, 0000-0003-0800-3663
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Volume Title
Publisher
Universidad Autonoma Metropolitana. Unidad Iztapalapa.
Abstract
Description
Las especies del género Dictyota presentan una alta plasticidad fenotípica que contrasta con escasos caracteres morfológicos diagnósticos, lo cual ha llevado a identificar especies con cierta incertidumbre en el Golfo de México. Estudios recientes a nivel mundial refieren filogenias de especies de Dictyota, los que serán la base para contrastar e interpretar los resultados de este estudio. Objetivos. En este trabajo se determina la presencia de una nueva especie para la ciencia del género Dictyota, encontrada en tres localidades del estado de Veracruz, México (Playa Hermosa, Punta Puntillas y Villa Rica). Métodos. Se realizaron análisis filogenéticos y moleculares de secuencias parciales de los genes psbA y cox1, que fueron complementados con análisis morfológicos. Resultados. En los análisis filogenéticos de las secuencias parciales de los genes psbA y cox1, se obtuvo que las muestras de la nueva especie forman un clado monofilético bien soportado. Además, los índices de divergencia genética obtenidos, se encuentran dentro de los valores interespecíficos para el género, lo que permite segregar a Dictyota chalchicueyecanensis sp. nov. de las demás especies del género. Morfológicamente esta nueva especie se caracteriza por presentar un talo erecto, sin iridiscencia, de consistencia rígida al tacto, con pie de fijación al sustrato de forma discoide, de color café claro in situ, ápices redondeados, ramificación dicotómica, con márgenes dentados de forma triangular a espinosa dirigidos hacia los ápices. Esporangios aislados o agrupados en ambas superficies del talo que regularmente germinan en las porciones interdicotómicas basales del mismo. Conclusiones. Los resultados anteriores amplían la diversidad del género Dictyota a nivel mundial, incorporando a D. chalchicueyecanensis como una nueva especie probablemente endémica de México.
Species of the Dictyota genus have a high phenotypic plasticity that contrasts with their limited morphological diagnostic characteristics, which has led to some uncertainty in identifying species in the Gulf of Mexico. Recent studies worldwide have focused on Dictyota species phylogenies, which are the basis for contrasting and interpreting the results of this study. Goals. In our research, we found evidence of a new species belonging to the Dictyota genus in three localities in the state of Veracruz, Mexico (Playa Hermosa, Punta Puntillas y Villa Rica). Methods. Phylogenetic and molecular analyses of partial sequences of the psbA and cox1 genes were performed, complemented by morphological analysis. Results. In phylogenetic analysis of partial sequences of psbA and cox1, we established that samples of the new species form a well-supported monophyletic clade. In addition, the genetic divergence values that were obtained are within the interspecific values for the genus, allowing us to segregate the Dictyota chalchicueyecanensis sp. nov. from the rest of the species of this genus. Morphologically this new species is characterized by an erect thallus, light brown and lacking iridescence, stiff to the touch, with a discoid holdfast, rounded apices, dichotomous branching, dentated margins, with minute teeth, triangular to spinose in shape that are directed toward the apices. Sporangia are isolated or grouped on both sides of the thallus and germinate regularly in interdichotomous basal portions. Conclusion. These results allow us to expand the diversity of the genus Dictyota worldwide, incorporating D. chalchicueyecanensis as a probable new species endemic to Mexico.
Species of the Dictyota genus have a high phenotypic plasticity that contrasts with their limited morphological diagnostic characteristics, which has led to some uncertainty in identifying species in the Gulf of Mexico. Recent studies worldwide have focused on Dictyota species phylogenies, which are the basis for contrasting and interpreting the results of this study. Goals. In our research, we found evidence of a new species belonging to the Dictyota genus in three localities in the state of Veracruz, Mexico (Playa Hermosa, Punta Puntillas y Villa Rica). Methods. Phylogenetic and molecular analyses of partial sequences of the psbA and cox1 genes were performed, complemented by morphological analysis. Results. In phylogenetic analysis of partial sequences of psbA and cox1, we established that samples of the new species form a well-supported monophyletic clade. In addition, the genetic divergence values that were obtained are within the interspecific values for the genus, allowing us to segregate the Dictyota chalchicueyecanensis sp. nov. from the rest of the species of this genus. Morphologically this new species is characterized by an erect thallus, light brown and lacking iridescence, stiff to the touch, with a discoid holdfast, rounded apices, dichotomous branching, dentated margins, with minute teeth, triangular to spinose in shape that are directed toward the apices. Sporangia are isolated or grouped on both sides of the thallus and germinate regularly in interdichotomous basal portions. Conclusion. These results allow us to expand the diversity of the genus Dictyota worldwide, incorporating D. chalchicueyecanensis as a probable new species endemic to Mexico.
Keywords
BIOLOGÍA Y QUÍMICA