title: MESOPHYLLUM SPHAERICUM SP. NOV. (CORALLINALES, RHODOPHYTA): A NEW MAËRL-FORMING SPECIES FROM THE NORTHEAST ATLANTIC(1).
abstract: Mesophyllum sphaericum sp. nov. is described based on spherical maërl individuals (up to 10 cm) collected in a shallow subtidal maërl bed in Galicia (NW Spain). The thalli of these specimens are radially organized, composed of arching tiers of compact medullary filaments. Epithallial cells have flattened to rounded outermost walls, and they occur in a single layer. Subepithallial initials are as long as, or longer than the daughter cells that subtend them. Cell fusions are abundant. Multiporate asexual conceptacles are protruding, mound-like with a flattened pore plate, lacking a peripheral raised rim. Filaments lining the pore canal and the conceptacle roof are composed of five to six cells with straight elongate and narrow cells at their base. Carposporangial conceptacles are uniporate, protruding, and conical. Spermatangial conceptacles were not observed. Molecular results placed M. sphaericum near to M. erubescens, but M. sphaericum is anatomically close to M. canariense. The examination of the holotype and herbarium specimens of M. canariense indicated that both species have pore canal filaments with elongate basal cells, but they differ in number of cells (five to six in M. sphaericum vs. four in M. canariense). Based on the character of pore canal filaments, M. canariense shows similarities with M. erubescens (three to five celled). The outermost walls of epithallial cells of M. canariense are flared compared to the round to flattened ones of M. erubescens, the latter being widely accepted for the genus Mesophyllum. The addition of M. sphaericum as new maërl-forming species suggests that European maërl beds are more biodiverse than previously understood.
authors.affiliation: Laboratorio de Algas Marinas, Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de A Coruña. Campus de A Zapateira, S/N. A Coruña. E-15071, SpainDepartment of Botany, National Museum of Natural History, Smithsonian Institution, Washington, D.C., 20560, USADepartamento de Biología Marina, Universidad de Baja California Sur (UABCS). Apartado postal 19-B, km. 5.5 Carretera al sur, La Paz, B.C.S. 23080, MexicoDivision of Life Sciences, Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaDepartamento de Biología Vegetal (Botánica), Universidad de La Laguna, La Laguna, Canary Islands, E-38271, SpainDivision of Life Sciences, Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaLaboratorio de Algas Marinas, Departamento de Biología Animal, Biología Vegetal y Ecología. Universidad de A Coruña. Campus de A Zapateira, S/N. A Coruña. E-15071, Spain.
authors.forename: Viviana
authors.initials: V
authors.lastname: Peña
authors.affiliation: Laboratorio de Algas Marinas, Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de A Coruña. Campus de A Zapateira, S/N. A Coruña. E-15071, SpainDepartment of Botany, National Museum of Natural History, Smithsonian Institution, Washington, D.C., 20560, USADepartamento de Biología Marina, Universidad de Baja California Sur (UABCS). Apartado postal 19-B, km. 5.5 Carretera al sur, La Paz, B.C.S. 23080, MexicoDivision of Life Sciences, Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaDepartamento de Biología Vegetal (Botánica), Universidad de La Laguna, La Laguna, Canary Islands, E-38271, SpainDivision of Life Sciences, Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaLaboratorio de Algas Marinas, Departamento de Biología Animal, Biología Vegetal y Ecología. Universidad de A Coruña. Campus de A Zapateira, S/N. A Coruña. E-15071, Spain.
authors.forename: Walter H
authors.initials: WH
authors.lastname: Adey
authors.affiliation: Laboratorio de Algas Marinas, Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de A Coruña. Campus de A Zapateira, S/N. A Coruña. E-15071, SpainDepartment of Botany, National Museum of Natural History, Smithsonian Institution, Washington, D.C., 20560, USADepartamento de Biología Marina, Universidad de Baja California Sur (UABCS). Apartado postal 19-B, km. 5.5 Carretera al sur, La Paz, B.C.S. 23080, MexicoDivision of Life Sciences, Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaDepartamento de Biología Vegetal (Botánica), Universidad de La Laguna, La Laguna, Canary Islands, E-38271, SpainDivision of Life Sciences, Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaLaboratorio de Algas Marinas, Departamento de Biología Animal, Biología Vegetal y Ecología. Universidad de A Coruña. Campus de A Zapateira, S/N. A Coruña. E-15071, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Riosmena-Rodríguez
authors.affiliation: Laboratorio de Algas Marinas, Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de A Coruña. Campus de A Zapateira, S/N. A Coruña. E-15071, SpainDepartment of Botany, National Museum of Natural History, Smithsonian Institution, Washington, D.C., 20560, USADepartamento de Biología Marina, Universidad de Baja California Sur (UABCS). Apartado postal 19-B, km. 5.5 Carretera al sur, La Paz, B.C.S. 23080, MexicoDivision of Life Sciences, Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaDepartamento de Biología Vegetal (Botánica), Universidad de La Laguna, La Laguna, Canary Islands, E-38271, SpainDivision of Life Sciences, Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaLaboratorio de Algas Marinas, Departamento de Biología Animal, Biología Vegetal y Ecología. Universidad de A Coruña. Campus de A Zapateira, S/N. A Coruña. E-15071, Spain.
authors.forename: Moon-Yung
authors.initials: MY
authors.lastname: Jung
authors.affiliation: Laboratorio de Algas Marinas, Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de A Coruña. Campus de A Zapateira, S/N. A Coruña. E-15071, SpainDepartment of Botany, National Museum of Natural History, Smithsonian Institution, Washington, D.C., 20560, USADepartamento de Biología Marina, Universidad de Baja California Sur (UABCS). Apartado postal 19-B, km. 5.5 Carretera al sur, La Paz, B.C.S. 23080, MexicoDivision of Life Sciences, Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaDepartamento de Biología Vegetal (Botánica), Universidad de La Laguna, La Laguna, Canary Islands, E-38271, SpainDivision of Life Sciences, Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaLaboratorio de Algas Marinas, Departamento de Biología Animal, Biología Vegetal y Ecología. Universidad de A Coruña. Campus de A Zapateira, S/N. A Coruña. E-15071, Spain.
authors.forename: Julio
authors.initials: J
authors.lastname: Afonso-Carrillo
authors.affiliation: Laboratorio de Algas Marinas, Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de A Coruña. Campus de A Zapateira, S/N. A Coruña. E-15071, SpainDepartment of Botany, National Museum of Natural History, Smithsonian Institution, Washington, D.C., 20560, USADepartamento de Biología Marina, Universidad de Baja California Sur (UABCS). Apartado postal 19-B, km. 5.5 Carretera al sur, La Paz, B.C.S. 23080, MexicoDivision of Life Sciences, Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaDepartamento de Biología Vegetal (Botánica), Universidad de La Laguna, La Laguna, Canary Islands, E-38271, SpainDivision of Life Sciences, Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaLaboratorio de Algas Marinas, Departamento de Biología Animal, Biología Vegetal y Ecología. Universidad de A Coruña. Campus de A Zapateira, S/N. A Coruña. E-15071, Spain.
authors.forename: Han-Gu
authors.initials: HG
authors.lastname: Choi
authors.affiliation: Laboratorio de Algas Marinas, Departamento de Biología Animal, Biología Vegetal y Ecología, Universidad de A Coruña. Campus de A Zapateira, S/N. A Coruña. E-15071, SpainDepartment of Botany, National Museum of Natural History, Smithsonian Institution, Washington, D.C., 20560, USADepartamento de Biología Marina, Universidad de Baja California Sur (UABCS). Apartado postal 19-B, km. 5.5 Carretera al sur, La Paz, B.C.S. 23080, MexicoDivision of Life Sciences, Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaDepartamento de Biología Vegetal (Botánica), Universidad de La Laguna, La Laguna, Canary Islands, E-38271, SpainDivision of Life Sciences, Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, KoreaLaboratorio de Algas Marinas, Departamento de Biología Animal, Biología Vegetal y Ecología. Universidad de A Coruña. Campus de A Zapateira, S/N. A Coruña. E-15071, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Bárbara
keywords: Corallinales; Galicia; Iberian Peninsula; Mesophyllum canariense; Mesophyllum erubescens; Mesophyllum sphaericum; NE Atlantic; maërl; nuclear SSU rDNA; rhodolith