Browsing by Author "Schils, Tom"
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- The correct identification of the species going under the name Scizymenia dubyi (Schizymeniaceae, Rhodophyta) in the Azores, based on molecular and morphological evidences.Publication . Gabriel, Daniela; Schils, Tom; Neto, Ana I.; Fredericq, Suzanne
- Genetic diversity of Gibsmithia hawaiiensis complex (Dumontiaceae, Rhodophyta)Publication . Gabriel, Daniela; Draisma, Stefano; Schmidt, William E.; Schils, Tom; Sauvage, Thomas; Maridakis, Clio; Gurgel, Carlos Frederico Deluqui; Lim, Phaik Eem; Harris, D. J.; Fredericq, SuzanneABSTRACT: The genus Gibsmithia was erected to accommodate a species with the peculiar combination of gelatinous lobes rising from cartilaginous stalks. Based on G. hawaiiensis from Hawaii, it remained monotypic for over 20 years, when three additional species were described from Australia. G. hawaiensis is unique for its furry appearance due to cortical filaments beyond the surface. Gibsmithia have been reported from the Indian Ocean and central and western Pacific, with G. hawaiensis having the widest distribution. Genetic studies based on COI, rbcL and UPA, reveal that G. hawaiiensis is monophyletic with nine distinct species sharing a similar habit. G. hawaiiensis complex exhibits high genetic diversity in Indomalaysia region, with different species presenting genetically variable populations. Species restricted to isolated region as Hawaii or the Red Sea comprises genetically conserved populations. Four of those cryptic species can be distinguished based on characters previously regarded as morphological plasticity: the generitype and the new species G. eilatensis, G. indomalayensis and G. lata distributa. Because specimens of the other species are only available dried onto herbarium paper or in silica-gel, their reproductive characters can not be characterized. New reports of the complex are given to Madagascar, Europa Island, the Red Sea and Guam, and also to new regions of Malaysia, Indonesia, the Philippines and the French Polynesia.
- Got Talent: Peyssonnelia globally showcases its skillsPublication . Gabriel, Daniela; Krayesky, David; Norris, James N.; Schmidt, William E.; Schils, Tom; Fredericq, SuzanneABSTRACT: The crust forming genus Peyssonnelia Decaisne is a taxon of great ecological importance, with some species involved in the establishment of rhodoliths. Comparative morphological and molecular analyses demonstrate a greater diversity of peyssonnelioid species than was previously reported. In chloroplast-encoded rbcL-based trees, species referred to as Peyssonnelia in the literature do not group together, but are scattered among other genera that were not currently placed in the Peyssonneliaceae. Two recently reported genera for the Gulf of Mexico, “ Polystrata” and Metapeyssonnelia, were excluded from the family, and together with a third clade are nested inside the Rhizophyllidaceae of the Dumontiaceae-complex. The Rhizophyllidaceae is newly reported for the Gulf of Mexico, with six species. The number of distinct species of Peyssonneliaceae now present in the Gulf of Mexico has increased from 6 to 21. On the other hand, the number of Peyssonnelia reported for the Azores was reduced from five to one species. Some species placed in Cruoriella and Cruoriopsis actually belong in the Peyssonneliaceae. New combinations are being proposed to accommodate known and new species in Cruoriella, and in two formerly monotypic genera, Sonderophycus and Riquetophycus. The Peyssonneliaceae forms a monophyletic assemblage that could not be maintained in the Gigartinales and thus a new order was constituted, Peyssonneliales, unrelated to the cluster of families centred around the Halymeniaceae of the Halymeniales, or the Gigartinaceae of the Gigartinales.
- Phylogenetic appraisal of the genus Platoma (Nemastomatales, Rhodophyta), including life history and morphological observations on P. cyclocolpum from the Azores.Publication . Gabriel, Daniela; Parente, Manuela I.; Neto, Ana I.; Raposo, Monica; Schils, Tom; Fredericq, SuzanneThe red algal genus Platoma Schmitz (Schizymeniaceae, Nemastomatales) with type Platoma cyclocolpum (Montagne) Schmitz was originally described from the Canary Islands. Life history studies were conducted on P. cyclocolpum from the Azores under 10uC/8:16 light (L):dark (D), 15uC/16:8 L:D, and 23uC/natural daylight regimes in culture. Three nonreproductive modes of thallus development resulted from germinating carpospores: (1) a permanent crust, (2) a filiform, nonfoliose erect thallus occasionally attached by a holdfast composed of cell aggregations, and (3) a filiform, nonfoliose erect thallus has been reported previously for populations from the Canary Islands, but the latter two have not been described before. Platoma cyclocolpum is widely reported in the literature, but specimens under that name from Madagascar are identified here as Platoma chrysymenioides Gavio et al., a deepwater species first described from the northern Gulf of Mexico and now recorded for the entire gulf. Genuine P. cyclocolpum specimens from the Azores, Madeira, and the Canary Islands were sequenced for chloroplast-encoded rbcL, and phylogenetic relationships of four Platoma species are discussed. A table listing diagnostic morphological and anatomical features of Platoma species is provided.
- Predaea feldmannii subsp. azorica (Nemastomataceae, Nemastomatales), a new subspecies of red algae (Rhodophyta) from the AzoresPublication . Gabriel, Daniela; Schils, Tom; Neto, Ana I.; Paramio, Luz; Fredericq, SuzanneThe red algal genus Predaea (Rhodophyta, Nemastomataceae, Nemastomatales) currently comprises 20 species found in tropical to temperate waters worldwide. The species going under the name Predaea feldmannii (Nemastomataceae, Nemastomatales) in the Azores is here reduced to subspecies rank as P. feldmannii subsp. azorica on the basis of comparative morphology and rbcL sequence analysis. The evidence presented here includes a phylogenetic tree inferred from chloroplast-encoded rbcL sequences of selected members of the Nemastomatales. P. feldmannii subsp. azorica shares with P. feldmannii subsp. feldmannii linear-oblong outer cortical cells, dichotomously branched cortical fascicles, a large number of auxiliary nutritive cells per cluster, and gonimoblast initiation from the incoming connecting filament near its point of fusion with the auxiliary cell. Differences include a sac-like, lobed thallus and occasional lateral cells on the carpogonial branch in the Azorean subspecies, versus a subcylindrical, subdichotomous habit with marginal lobes, and lack of lateral cells on the carpogonial branch in P. feldmannii subsp. feldmannii. The known distribution of P. feldmannii subsp. feldmannii is worldwide in tropical regions and so far P. feldmannii subsp. azorica is known only from the Azores.
- Taxonomic studies in the Schizymeniaceae (Nemastomatales, Rhodophyta): on the identity of Schizymenia sp. in the Azores and the generic placement of Nemastoma confusumPublication . Gabriel, Daniela; Schils, Tom; Parente, Manuela I.; Draisma, Stefano; Neto, Ana I.; Fredericq, SuzanneComparative rbcL sequence analysis indicates that the species going under the name Schizymenia dubyi in the Azores should be referred to as S. apoda. Sequences of Schizymenia specimens from China and Namibia were also identified as S. apoda, of which the type locality is the Cape Province in South Africa. Schizymenia dubyi, described from Atlantic France, is clearly a distinct species that we here report for Japan and Sicily in the Mediterranean Sea. Both Schizymenia species, along with an unreported species from Japan, are distinct from S. pacifica described from Washington, in the Pacific Coast of North America. Secondary pit connections were observed in gametophytes of S. apoda from the Azores, a previously unknown character for the Nemastomatales. Examination of type material of Nemastoma confusum indicates that this species, currently placed in the Nemastomataceae, should be transferred to the genus Platoma in the Schizymeniaceae. A morphological comparison between Platoma confusum (Kraft & John) comb. nov. with descriptions of P. cyclocolpum and P. chrysymenioides suggests that the three species are closely related.