Reassessment of Tristan da Cunha Gelidium (Gelidiales, Rhodophyta) species

2020 ◽  
Vol 63 (5) ◽  
pp. 455-462
Author(s):  
D. Wilson Freshwater ◽  
Sue Scott ◽  
Enrico M. Tronchin ◽  
Gary W. Saunders
Keyword(s):  
Southern Africa ◽  
Endemic Species ◽  
Red Algae ◽  
Genetic Group ◽  
The Third ◽  
Tristan Da Cunha

AbstractThree endemic species of Gelidium have been described from the remote Tristan da Cunha archipelago. A recent barcode survey of Tristan da Cunha red algae in combination with the clarification of vouchers for previously sequenced specimens has prompted a molecular and morphological reassessment of these species. Analyses of rbcL and COI-5P data indicated that all sequenced Tristan da Cunha specimens represented a single taxon, and furthermore that this genetic group was conspecific with Gelidium micropterum from southern Africa. Morphologically the Tristan da Cunha specimens represented either Gelidium concinnum or Gelidium regulare, and there was a grade of character states between both of these species, as well as G. micropterum. Based on these results the synonymy of G. concinnum and G. regulare under G. micropterum is proposed and an expanded description of G. micropterum provided. None of the studied Tristan da Cunha specimens clearly fit the description of the third endemic species, Gelidium inflexum, and its status could not be determined.

scholarly journals The Sinking of Another Tristan da Cunha Moss Endemic and Its Phytogeographical Consequences

2020 ◽  
Vol 89 (3) ◽  
Author(s):  
Ryszard Ochyra ◽  
Vítězslav Plášek
Keyword(s):  
Atlantic Ocean ◽  
Southern Hemisphere ◽  
Endemic Species ◽  
Distribution Patterns ◽  
South Atlantic ◽  
South Atlantic Ocean ◽  
Original Material ◽  
The Third ◽  
Tristan Da Cunha ◽  
Central South

<p>The original material of <em>Isopterygium tristaniense </em>Dixon, an endemic species of the Tristan da Cunha archipelago in the central South Atlantic Ocean, is taxonomically evaluated and some details of its morphology are illustrated. The species is found to be conspecific with the Holarctic <em>Pseudotaxiphyllum elegans </em>(Brid.) Z.Iwats. and it is the third record of the species in the Southern Hemisphere. The global distribution of this species is reviewed and the distribution patterns of the South Atlantic mosses are briefly discussed.</p>

A Social Sonic Paradigm

2021 ◽  
pp. 540-554
Author(s):  
Tegan Bristow ◽  
João Orecchia Zúñiga
Keyword(s):  
Case Studies ◽  
Southern Africa ◽  
Political Engagement ◽  
Sound Art ◽  
Intellectual Engagement ◽  
The Third ◽  
Primary Focus ◽  
Definition Of ◽  
Forms Of Knowledge

This chapter presents an examination of why—in contemporary Africa, with Southern Africa as the primary focus—there are very few artists working with sound in a manner that fits the paradigm of sound art as it is known in Euro-America. Emphasis is not placed on a lack of intellectual engagement, which is significant in the Euro-American definition of sound art. What is presented does not aim to deviate from this, but rather acts to affirm an engagement with alternative forms of knowledge and mechanisms of sound found in the South. Three areas are explored; these however are interlinked and do not stand alone. The first is an understanding of the practice of interdisciplinarity as political engagement. The second explores the role of community and communal interaction with sound and how this is fundamental to form in the region. The third extends this by showing how the histories of knowledge and power are fundamental to these explorations in the region, emphasizing how contemporary explorations of sound are used to both contain and shift these histories. The chapter takes shape with the use of case studies and draws on interviews conducted by the authors.

scholarly journals Intraspecific Molecular Variation of Allium ursinum (Amaryllidaceae) Across the Border of Two Subspecies Distribution Ranges

2015 ◽  
Vol 57 (1) ◽  
pp. 31-43
Author(s):  
Kaja Rola ◽  
Anna Lenart-Boroń ◽  
Piotr Boroń ◽  
Piotr Osyczka
Keyword(s):  
Genetic Variability ◽  
Hybrid Zone ◽  
Mantel Test ◽  
Genetic Group ◽  
Secondary Contact ◽  
Putative Hybrid ◽  
Morphological Pattern ◽  
The Third ◽  
Allium Ursinum ◽  
Distribution Ranges

Abstract The study investigates the genetic differentiation among two subspecies of Allium ursinum L., namely A. ursinum subsp. ursinum and subsp. ucrainicum as well as their putative hybrid that is represented by individuals with intermediate morphology. Inter-Simple Sequence Repeats (ISSR) were applied to determine the status of intermediate morphotypes in terms of their genetic pattern and to assess the level of genetic variability within and between various populations of A. ursinum. The study comprises 144 specimens from nine populations along the east-west transect in Poland, which includes localities of both subspecies and their putative hybrid. Among the examined populations, 48 bands were amplified, of which 45 were found to be polymorphic. The principal coordinate analysis (PCoA), the neighbour-net analysis and Mantel test showed a strong correlation between genetic variability and geographic distance. Analysis of molecular variance (AMOVA) revealed that a greater proportion of total genetic variation resided within populations rather than among them. The Structure Bayesian clustering analysis revealed the presence of three distinct genetic groups within studied populations, where ‘eastern’ genotypes correspond to A. ursinum subsp. ucrainicum, and ‘western’ to subsp. ursinum; whereas the third genetic group has the largest share in the individuals occurring at the border of the distribution ranges of both subspecies. The emergence of the third genetic group is probably an effect of hybridization events occurring within the secondary contact zone. Typical morphologically intermediate populations occur only in a relatively narrow geographical zone, but the hybrid zone revealed by molecular markers is actually much wider than it is suggested by the morphological pattern of individuals. The current distribution pattern of both subspecies of A. ursinum and their hybrid zone is related to the two main directions of postglacial migration of Fagus sylvatica to the area of Poland. The hybrid zone arose as an effect of the secondary contact of two divergent lineages of A. ursinum.

Fourth addendum to the synoptic review of red algal genera

2019 ◽  
Vol 62 (4) ◽  
pp. 355-367 ◽  
Author(s):  
Craig W. Schneider ◽  
Michael J. Wynne
Keyword(s):  
New Taxa ◽  
Red Algae ◽  
New Genera ◽  
Half Century ◽  
Hierarchical Framework ◽  
The Third ◽  
The Past ◽  
Red Algal ◽  
Molecular Sequencing

Abstract The fourth addendum to Schneider and Wynne’s 2007 “A synoptic review of the classification of red algal genera a half century after Kylin’s 1956 ‘Die Gattungen der Rhodophyceen’” is presented, covering the names of genus- and higher-level taxa added or modified since our third addendum (Bot. Mar. 59: 397–404). Since that synopsis, we added 21 new genera in a first addendum, 27 in the second, and 40 in the third, demonstrating the increasing amount of genetic work over more than a decade. In this fourth addendum, we add 58 new genera to the list of red algae as well as many new taxa in the hierarchical framework over the past 3 years. Based upon molecular sequencing, other genera reinstated from synonymy studies are included.

scholarly journals Preface

1965 ◽  
Vol 249 (759) ◽  
pp. 258-258
Keyword(s):  
Geographical Distribution ◽  
Endemic Species ◽  
Scientific Interest ◽  
Ecological Stability ◽  
Ecological Balance ◽  
Tristan Da Cunha ◽  
Ecological Evolution ◽  
Gough Island ◽  
Island Group

The four islands of the Tristan da Cunha-Gough Island group are very isolated. They contain a unique fauna and flora. Knowledge of these is very incomplete in important respects. Such knowledge could not only help towards understanding the origins of the geographical distribution of plants and animals, it could also throw valuable light on the factors governing colonization of isolated regions. But it is not only the unique biota which is of scientific interest in these islands. We have here a natural ecological balance between the endemic species of an impoverished and therefore simple fauna and flora. Such islands could thus allow us to study with comparative ease the factors which control ecological stability; a study of the great importance to mankind today. Moreover, fortunately there have now been found in these islands evidence of datable remains of the geologically recent biota, so that there is a reasonable chance that we shall one day be able to trace the ecological evolution in time.

Viewpoint: Is the European attitude to GM products suffocating African development?

2005 ◽  
Vol 32 (12) ◽  
pp. 1069 ◽  
Author(s):  
Greg Bodulovic
Keyword(s):  
Southern Africa ◽  
Food Production ◽  
Agricultural Biotechnology ◽  
Genetically Modified ◽  
Gm Crops ◽  
Food Aid ◽  
African Development ◽  
The Third ◽  
Food Shortages ◽  
Developed Nations

Currently, parts of Southern Africa are experiencing the third major drought in five years. The previous two droughts greatly affected food production, resulting in food shortages, which necessitated the provision of food aid to the region by developed nations. However, some of the food aid included genetically modified (GM) crops, the supply of which triggered hostile reactions by southern African governments, and in one case resulted in food aid being withheld from people on the verge of starvation. This article will examine the background and reasons behind the condemnation of GM crops by southern African nations, and will consider whether the lack of support of agricultural biotechnology by European nations has contributed to this situation. Furthermore, the necessity of agricultural biotechnology in future African development will be considered.

scholarly journals Taxonomy and chorology of Corbichonia (Lophiocarpaceae s.l.) with further description of a new species from Southern Africa

Phytotaxa ◽  
2015 ◽  
Vol 218 (3) ◽  
pp. 227 ◽  
Author(s):  
Alexander P. Sukhorukov ◽  
Maria Kushunina
Keyword(s):  
South Africa ◽  
New Species ◽  
Southern Africa ◽  
Taxonomic Status ◽  
Herbarium Material ◽  
The Third ◽  
The Core ◽  
Morphological Differences ◽  
A New Species

A re-examination of the herbarium material has allowed to describe a new species, Corbichonia exellii, occurring in Southern Africa (Angola, Namibia and South Africa). C. exellii represents the third species in the genus. Morphological differences between all three Corbichonia species (C. decumbens, C. rubriviolacea, and C. exellii) are provided. The description of the genus is defined using the newly discovered characters (reproductive features). The taxonomy of all Corbichonia species (synonyms included) is provided, as well as maps for all species. The lectotypes of Orygia decumbens (basionym of Corbichonia decumbens) and O. mucronata (synonym of C. decumbens) are designated on specimens preserved, respectively, at BM and K. The genus Corbichonia, recently placed in Lophiocarpaceae, is markedly different from the core genus Lophiocarpus on the basis of embryological, morphological and carpological characters, and deserves further investigation concerning its taxonomic status.

Cytology of the fern flora of Tristan da Cunha

1968 ◽  
Vol 170 (1021) ◽  
pp. 361-379 ◽  
Keyword(s):  
Chromosome Number ◽  
Southern Hemisphere ◽  
Endemic Species ◽  
Special Interest ◽  
New Record ◽  
Atlantic Basin ◽  
High Chromosome Number ◽  
Tristan Da Cunha

Twenty species out of a total of twenty-six leptosporangiate ferns known to occur on Tristan da Cunha have been examined cytologically. Four species have been independently examined from Gough with concordant results. Hymenophyllum tunbrigense , included among the Tristan species, is a new record for the island. Other points of special interest about individual taxa include demonstration of an extremely high chromosome number ( n = 174) in the supposedly endemic species Eriosorus cheilanthoides , demonstration of the existence of two different cytotypes (one only present on Tristan) within Blechnum penna-marina in the southern hemisphere and of complex polyploid relationships affecting several other taxa which are discussed individually. In addition the cytological composition of the fern flora as a whole is discussed in relation to other temperate and tropical floras in or near the Atlantic basin.

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