Topic
Thorea
About: Thorea is a research topic. Over the lifetime, 30 publications have been published within this topic receiving 263 citations.
Papers
TL;DR: Findings indicate the Thoreaceae has been misclassified in the Batrachospermales and should be placed in its own order, theThoreales, characterized by having freshwater representatives with multiaxial gametophytes, a uniaXial chantransia stage, and pit plugs with two cap layers, the outer one of which is usually plate‐like.
Abstract: Representatives of the freshwater red algal family Thoreaceae were studied to resolve their taxonomic and phylogenetic status. Three specimens of Nemalionopsis and five collections of Thorea were examined for pit plug ultrastructure and analyzed for the sequences of the genes coding for the large subunit of RUBISCO (rbcL) and the small subunit of rRNA (18S rRNA). The phylogenetic trees generated from the two genes, and a combined tree all showed the Thoreaceae to be contained in a well-supported monophyletic clade that is separate from the other two families currently classified in the Batrachospermales, the Batrachospermaceae and the Lemaneaceae. In addition, secondary structure elements of the 18S rRNA gene were observed at positions 650 and 1145 (Escherichia coli numbering system) that are not present in other members of the Rhodophyta. The pit plugs of the gametophytic and chantransia stages of the Thoreaceae contain two cap layers, the outer one of which is typically plate-like, though occasionally inflated ones have been seen. No pit plug cap membrane has been observed. These findings indicate the Thoreaceae has been misclassified in the Batrachospermales and should be placed in its own order, the Thoreales. This order is characterized by having freshwater representatives with multiaxial gametophytes, a uniaxial chantransia stage, and pit plugs with two cap layers, the outer one of which is usually plate-like.
51 citations
TL;DR: North American populations and type specimens of Thorea and Nemalionopsis were compared using multivariate morphometrics and image analysis to recognise the separation of the two genera based on spore-bearing branch-to-assimilatory filament length ratio and assimilatory filament density.
Abstract: North American populations and type specimens of Thorea and Nemalionopsis were compared using multivariate morphometrics and image analysis. We continue to recognise the separation of the two genera based on spore-bearing branch-to-assimilatory filament length ratio and assimilatory filament density (≤0·3 and loose for Thorea and ≥0·6 and compressed for Nemalionopsis, respectively). Four species of Thorea were distinguished worldwide: T. hispida (syn. T. andina, T. lehmannii, T. ramosissima), T. violacea (syn. T. bachmannii, T. brodensis, T. gaudichaudii, T. okadae, T. prowsei and T. riekei), T. clavata and T. zollingeri. The former two species have variable branched, non-clavate assimilatory filaments, whereas the latter two have unbranched, clavate assimilatory filaments. Thorea hispida has copious secondary branches while T. violacea is sparsely branched. Thorea clavata is differentiated from T. zollingeri by having fewer monosporangia per cluster. Two of these species were found in North America: T. h...
29 citations
TL;DR: The populations of Thorea from central Mexico and south‐eastern Brazil corroborated the known world distribution for T. hispida, consisting dommantly of tropical to subtropical rainforests, sometimes extending into warm temperate areas.
Abstract: Phycology Laboratory National Autonomous University of Mexico Ciudad Universitaria, AP 70-620, Coyoacan, 04510, Mexico DF
19 citations
TL;DR: The characteristics of the Thoreaceae, with a distinctive developmental pattern of the juvenile gametophyte and the occurrence of two morphological types in the ‘Chantransia’ stage, support the proposal to elevate it to the ordinal level.
Abstract: Seven populations (six in culture and one sampled directly from nature) of the freshwater red algal families Batrachospermaceae, Lemaneaceae and Thoreaceae were examined, involving three species of Batrachospermum, two of Paralemanea and one of Thorea. All ‘Chantransia’ stages ultimately produced juvenile gametophytes. The production of juvenile gametophytes in the three populations of Batrachospermum was generally most abundant at 15°C and low irradiances (47−68 μmol photons m−2 s−1). The most abundant gametophyte development in the Paralemanea species was observed at 10°C and low or high irradiances (47−142 μmol photons m−2 s−1). Gametophyte production in Thoreaceae occurred at higher temperatures (20°C) and also at low irradiances. In species of the Batrachospermaceae and Lemaneaceae, the ‘elimination cells’ can be situated on the basal or suprabasal cell of the juvenile gametophyte, but the position is usually fixed in individual species. The presence and position of the elimination cells rem...
18 citations
TL;DR: The morphology and ontogeny of Thorea riekei sp.
Abstract: SUMMARY
The morphology and ontogeny of Thorea riekei sp. nov. from a spring-fed stream in Landa Park, New Braunfels, Texas, are described. The organism was isolated into unialgal culture and grown through its complete life history, stages of which are illustrated by photomicrographs. Comparative studies were made of herbarium specimens of Thorea species from several United States herbaria. A review of the taxonomic literature on the genus Thorea revealed a considerable number of inaccurate and doubtful determinations of herbarium specimens. A brief study of the ultrastructure of T. riekei is included.
18 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2019 | 1 |
| 2018 | 2 |
| 2015 | 3 |
| 2012 | 1 |
| 2010 | 1 |
| 2006 | 1 |