17 research outputs found

    Genetic diversity of sympatric Schizymenia dubyi and S. apoda (Schizymeniaceae, Rhodophyta) in Wellington Harbour, New Zealand

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    Schizymenia dubyi is reported as a new introduction in Wellington, which already has introduced S. apoda. These species coexist in tidepools and the crustose sporophyte is for the first time reported from this population. The diversity and species status of these two species was explored using mitochondrial, plastid and nuclear markers. Haplotypes of rbcL in New Zealand samples of S. dubyi match a haplotype found in Australia that was considered as ‘introgressed’ into S. apoda. COI haplotypes of S. dubyi from New Zealand are also similar to specimens from Australia and Europe, although New Zealand S. apoda samples have a unique haplotype. ITS ribotypes of S. dubyi from New Zealand also are shared with Australia and Europe, while again S. apoda ribotypes are unique. Phylogenetic and network analyses show that these two species are very closely related, and the hypothetical ‘introgressed’ nature of specimens is not supported by phylogenetic analyses. In addition, species delimitation methods are not congruent and do not clarify the species status of these two entities. Morphologically, these species are not distinct, except that in S. dubyi the cystocarp ostiole may be in a depression. The apparent incongruence between markers, leading to the hypothesis of introgression, is probably due to the early stages of the speciation process during which species have a ‘paraphyletic’ phase, in which stochastic incomplete lineage sorting leads to ancestral haplotypes being retained differentially, versus hybridization, introgression and non-maternal inheritance of organelles. Whether these two entities are distinct species needs to be reconsidered, as many species criteria are not met (e.g. monophyly) or need to be tested (e.g. reproductive barriers)

    Why one species in New Zealand, Pugetia delicatissima (Kallymeniaceae, Rhodophyta), should become two new genera, Judithia gen. nov. and Wendya gen. nov.

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    © 2015 British Phycological Society. Blade-forming red algae occur worldwide and, prior to DNA sequencing, had been notoriously difficult to identify and classify, especially when lacking critical reproductive features. This, coupled in New Zealand with many longstanding assumptions that taxa were identical to non-New Zealand species or genera, resulted in many misapplied names. Pugetia delicatissima R.E. Norris, an endemic New Zealand blade-forming species of the family Kallymeniaceae, is actually comprised of one existing and one new species belonging to two distinct genera, as established by our phylogenetic analyses of DNA sequences from the rbcL gene. Analyses of combined rbcL and LSU genes showed that neither is closely related to the generitype of Pugetia, the northern-eastern Pacific, P. fragilissima Kylin. We propose the names Judithia and Wendya for these two newly revealed genera. In addition to diagnostic rbcL and LSU sequences, Judithia is morphologically and anatomically characterized by rounded to oblong blades that do not taper basally at the stipe, loosely aggregated surface cortical cells and cystocarps lacking both a pericarp and an ostiole, all features observed in the holotype of P. delicatissima. Wendya, in contrast, is characterized by blades that taper both apically and basally, compactly arranged surface cortical cells and cystocarps that have both a pericarp and a distinct ostiole. The two genera also are distinguished from one other, as well as from Pugetia by features of pre- and post-fertilization development, including the number of subsidiary cells produced on carpogonial and auxiliary branch systems, whether subsidiary cells in the carpogonial branch system fuse with the supporting cell or not, and the site of origin of gonimoblast cells. Although small in area, New Zealand hosts ten of the 27 currently recognized genera in the Kallymeniaceae and is the southern-hemisphere region of greatest generic diversification in this family

    Misure, idee per un museo della scienza

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    L'organizzazione dell'evento ha richiesto: l'individuazione di un tema comune per la mostra che tutti i musei avrebbero poi sviluppato secondo le proprie competenze, la preparazione e la scelta delle modalità espositive, la scelta e preparazione dei materiali da esporre per il museo di arte e giacimenti minerari. Questo ha comportato la scelta di lastre di rocce ornamentali e il tipo di taglio da effettuare, la realizzazione di materiale espositivo (fotografie e disegni) da esporre insieme alle descrizioni didascaliche dei contenuti della vetrina. Preparazione della sezione del testo del catalogo riguardante l’allestimento della vetrina del museo di arte e giacimenti minerari

    Meridionella gen. nov., a New Genus of Cystocloniaceae (Gigartinales, Rhodophyta) from the Southern Hemisphere, Including M. obtusangula comb. nov. and M. antarctica sp. nov.

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    The classification of Cystoclonium obtusangulum has been questioned since the species was first described by Hooker and Harvey as Gracilaria? obtusangula. The objective of this study was to provide the first comprehensive taxonomic analysis of Cystoclonium obtusangulum, based on DNA sequences coupled with morphological observations made on syntype specimens and new collections. Sequence divergences of rbcL, UPA, and COI-5P, and maximum-likelihood phylogenies for rbcL and 18S demonstrated that specimens identified as Cystoclonium obtusangulum represent a clade of two distinct species that are distantly related to the generitype Cystoclonium purpureum. A new genus, Meridionella gen. nov., is proposed for this clade. The two species placed in this new genus were morphologically indistinguishable cryptic species, but have disjunct distributions, with Meridionella obtusangula comb. nov. found from temperate to cold coasts of South America and the Falkland Islands and Meridionella antarctica sp. nov., occurring in Antarctic waters. Vegetative and reproductive characters of Meridionella gen. nov. are described, and implications of our results for the biogeography of the family Cystocloniaceae are discussed.Postprint2,23
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