scholarly journals Cyanobacteria Phylogenetic Studies Reveal Evidence for Polyphyletic Genera from Thermal and Freshwater Habitats

Diversity ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 298
Author(s):  
Rita Cordeiro ◽  
Rúben Luz ◽  
Vitor Vasconcelos ◽  
Vítor Gonçalves ◽  
Amélia Fonseca
Keyword(s):  
North Atlantic Ocean ◽  
Extreme Environments ◽  
Morphological Characteristics ◽  
Taxonomic Revision ◽  
Environmental Data ◽  
New Genera ◽  
Environmental Distribution ◽  
The North ◽  
Freshwater Habitats ◽  
Terrestrial Habitats

Cyanobacteria are among the most diverse morphological microorganisms that inhabit a great variety of habitats. Their presence in the Azores, a volcanic archipelago of nine islands in the middle of the North Atlantic Ocean, has already been reported. However, due to the high diversity of cyanobacteria habitats, their biodiversity is still understudied, mainly in extreme environments. To address this, a total of 156 cyanobacteria strains from Azores lakes, streams, thermal and terrestrial habitats were isolated. Identification was made based on a polyphasic approach using classical taxonomy (morphological characteristics and environmental data) and phylogeny among 81 strains assessed by maximum likelihood and Bayesian analysis of 16S rDNA partial sequences. The 156 isolates showed a high genera diversity (38) belonging to the orders Chroococcales, Nostocales, Oscillatoriales, and Synechococcales. Eleven new genera for the Azores habitats are here reported, reinforcing that cyanobacteria biodiversity in these islands is still much understudied. Phylogenetic analysis showed 14 clusters associated with these cyanobacteria orders, with evidence for six new genera and valuable information towards Microchaete/Coleospermum taxonomic revision that better reflects species environmental distribution. These results emphasize the need for cyanobacteria taxonomy revisions, through polyphasic studies, mainly in Synechococcales order and in the Microchaete/Coleospermum, Nostoc, and Anabaena genera.

More on snails and islands: molecular systematics and taxonomic revision of Setobaudinia Iredale (Gastropoda : Camaenidae) from the Kimberley, Western Australia, with description of new taxa

2013 ◽  
Vol 27 (6) ◽  
pp. 634 ◽  
Author(s):  
Francesco Criscione ◽  
Frank Köhler
Keyword(s):  
New Species ◽  
New Taxa ◽  
Morphological Characteristics ◽  
Taxonomic Revision ◽  
Sister Group ◽  
Northern Territory ◽  
Land Snails ◽  
North West ◽  
The North ◽  
High Precipitation

Setobaudinia Iredale, 1933 is a genus of camaenid land snails endemic to the Western Australian Kimberley. It comprises 20 currently recognised species, most of which occur within the north-western high precipitation zone between the Admiralty Gulf and Collier Bay and within less than 60 km distance from the coast. Exceptionally, two species are found on isolated limestone outcrops in the drier interior of the Victoria River District, Northern Territory. By studying the differentiation in shell and genital anatomy as well as in the mitochondrial markers 16S and COI, we revise the taxonomy of Setobaudinia and describe new taxa. The Northern Territory species S. victoriana Solem, 1985 is identified as a member of the genus Trachiopsis, which otherwise comprises species from the York Peninsula, Queensland. The species Damochlora spina Solem, 1985 is shown to be a member of the genus Setobaudinia. A new species from the eastern Kimberley has been identified as the sister group of Setobaudinia. It is placed in the new genus Kymatobaudinia for exhibiting morphological characteristics that differ from those of all other Setobaudinia species. In addition, we describe nine new species from coastal areas and islands off the cost throughout the south-west to north-west Kimberley: S. angustilabiata, sp. nov.; S. colmani, sp. nov.; S. incisa, sp. nov.; S. kessneri, sp. nov.; S. latilabiata, sp. nov.; S. longiflagellata, sp. nov.; S. malbyana, sp. nov.; S. minima, sp. nov.; S. plana, sp. nov. ZooBank Publication code: http://zoobank.org/References/3C953F1A-62E5-4CE5-9D5E-D8D5774B4059

SEM and TEM observations of sperm development in the testis of the freshwater fish Oreochromis mossambicus

1990 ◽  
Vol 48 (3) ◽  
pp. 58-59
Author(s):  
Daryl A. Cornish ◽  
George L. Smit
Keyword(s):  
Morphological Characteristics ◽  
Oreochromis Mossambicus ◽  
Breeding Cycle ◽  
Limited Information ◽  
North West ◽  
The North ◽  
Sem And Tem ◽  
Sperm Development ◽  
Ultrastructural Characteristics ◽  
The University

Oreochromis mossambicus is currently receiving much attention as a candidater species for aquaculture programs within Southern Africa. This has stimulated interest in its breeding cycle as well as the morphological characteristics of the gonads. Limited information is available on SEM and TEM observations of the male gonads. It is known that the testis of O. mossambicus is a paired, intra-abdominal structure of the lobular type, although further details of its characteristics are not known. Current investigations have shown that spermatids reach full maturity some two months after the female becomes gravid. Throughout the year, the testes contain spermatids at various stages of development although spermiogenesis appears to be maximal during November when spawning occurs. This paper describes the morphological and ultrastructural characteristics of the testes and spermatids.Specimens of this fish were collected at Syferkuil Dam, 8 km north- west of the University of the North over a twelve month period, sacrificed and the testes excised.

Zooplankton Biogeochemical Cycles

2017 ◽  
Author(s):  
Deborah Steinberg
Keyword(s):  
North Atlantic ◽  
North Atlantic Ocean ◽  
Significant Proportion ◽  
Biogeochemical Cycles ◽  
Biological Pump ◽  
The North ◽  
Particle Export ◽  
Chemical Cycling ◽  
Cycling Of Nutrients ◽  
Planktonic Communities

The structure of planktonic communities profoundly affects particle export and sequestration of organic material (the biological pump) and the chemical cycling of nutrients. This chapter describes the integral and multifaceted role zooplankton (both protozoan and metazoan) play in the export and cycling of elements in the ocean, with an emphasis on the North Atlantic Ocean and adjacent seas. Zooplankton consume a significant proportion of primary production across the world's oceans, and their metabolism plays a key role in recycling carbon, nitrogen, and other elements. The chapter also addresses how human or climate-influenced changes in North Atlantic zooplankton populations may in turn drive changes in zooplankton-mediated biogeochemical cycling.

scholarly journals Islands in the desert: environmental distribution modelling of endemic flora reveals the extent of Pleistocene tropical relict vegetation in southern Arabia

2019 ◽  
Vol 124 (3) ◽  
pp. 411-422 ◽  
Author(s):  
James S Borrell ◽  
Ghudaina Al Issaey ◽  
Darach A Lupton ◽  
Thomas Starnes ◽  
Abdulrahman Al Hinai ◽  
...  
Keyword(s):  
Environmental Variables ◽  
Narrow Range ◽  
Biodiversity Hotspot ◽  
Environmental Data ◽  
Distribution Data ◽  
Endemic Plants ◽  
Environmental Niche ◽  
Environmental Distribution ◽  
Southern Arabia ◽  
Endemic Flora

AbstractBackground and AimsSouthern Arabia is a global biodiversity hotspot with a high proportion of endemic desert-adapted plants. Here we examine evidence for a Pleistocene climate refugium in the southern Central Desert of Oman, and its role in driving biogeographical patterns of endemism.MethodsDistribution data for seven narrow-range endemic plants were collected systematically across 195 quadrats, together with incidental and historic records. Important environmental variables relevant to arid coastal areas, including night-time fog and cloud cover, were developed for the study area. Environmental niche models using presence/absence data were built and tuned for each species, and spatial overlap was examined.Key ResultsA region of the Jiddat Al Arkad reported independent high model suitability for all species. Examination of environmental data across southern Oman indicates that the Jiddat Al Arkad displays a regionally unique climate with higher intra-annual stability, due in part to the influence of the southern monsoon. Despite this, the relative importance of environmental variables was highly differentiated among species, suggesting that characteristic variables such as coastal fog are not major cross-species predictors at this scale.ConclusionsThe co-occurrence of a high number of endemic study species within a narrow monsoon-influenced region is indicative of a refugium with low climate change velocity. Combined with climate analysis, our findings provide strong evidence for a southern Arabian Pleistocene refugium in Oman’s Central Desert. We suggest that this refugium has acted as an isolated temperate and mesic island in the desert, resulting in the evolution of these narrow-range endemic flora. Based on the composition of species, this system may represent the northernmost remnant of a continuous belt of mesic vegetation formerly ranging from Africa to Asia, with close links to the flora of East Africa. This has significant implications for future conservation of endemic plants in an arid biodiversity hotspot.

Spatiotemporal evolution of the chlorophyll a trend in the North Atlantic Ocean

2018 ◽  
Vol 612 ◽  
pp. 1141-1148 ◽  
Author(s):  
Min Zhang ◽  
Yuanling Zhang ◽  
Qi Shu ◽  
Chang Zhao ◽  
Gang Wang ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Chlorophyll A ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Spatiotemporal Evolution ◽  
The North ◽  
The North Atlantic
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