Gondwanorchestia tristanensis gen. nov. sp. nov., a new southern hemisphere genus and species of talitrid amphipod (Amphipoda, Senticaudata, Talitridae)

Zootaxa ◽  
2020 ◽  
Vol 4748 (2) ◽  
pp. 375-381
Author(s):  
JAMES K. LOWRY ◽  
ALAN A. MYERS ◽  
JORGE PÉREZ-SCHULTHEISS

Material collected by the Norwegian Scientific Expedition to Tristan Da Cunha in the South Atlantic Ocean in the years 1937–1938 and later attributed by Stephensen, 1949 to Orchestia scutigerula Dana, 1852 has been re-examined and is described as a new genus and species, Gondwanorchestia tristanensis sp. nov. Orchestia scutigerula Dana, 1852 is transferred to Gondwanorchestia gen nov. and compared with G. tristanensis sp. nov. 

2020 ◽  
Vol 89 (3) ◽  
Author(s):  
Ryszard Ochyra ◽  
Vítězslav Plášek

<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>


The Condor ◽  
2003 ◽  
Vol 105 (3) ◽  
pp. 439-452 ◽  
Author(s):  
Richard Cuthbert ◽  
Peter G. Ryan ◽  
John Cooper ◽  
Geoff Hilton

Abstract The Atlantic Yellow-nosed Albatross (Thalassarche chlororhynchos) breeds only at the Tristan da Cunha archipelago and Gough Island in the central South Atlantic Ocean, and is threatened by mortality from longline fisheries operating in the South Atlantic. Demographic data have been collected from two study colonies on Gough Island and Tristan da Cunha for 20 years. Annual variation in the number of breeding birds was strongly correlated between the two islands, and over the whole study period both study populations have trended downward at around 1.2% per year. The number of established breeders on Gough Island has declined more rapidly, and significantly, at an annual rate of 2.3%. Monitoring established breeders may be a sensitive means of detecting population trends. Average breeding success (67–69%) and breeding frequency (66–65%) were very similar on the two islands. On Gough Island immature and adult annual apparent survival averaged 88 ± 3% and 92 ± 1%, respectively, and apparent survival from fledging to age 5 has averaged 31 ± 8%. Apparent adult survival on Tristan da Cunha averaged only 84 ± 2%. Annual survival of Tristan birds was negatively correlated with longline fishing effort in the South Atlantic Ocean. Population modeling predicts annual rates of decrease of 1.5–2.8% on Gough Island and 5.5% on Tristan da Cunha. Comparison with congeners suggests that the observed and predicted decreases are most likely to be caused by low adult and immature survival. The conservation status of Atlantic Yellow-nosed Albatrosses should be changed from Near Threatened to Endangered. Demografía y Tendencias Poblacionales del Albatros Thalassarche chlororhynchos Resumen. El albatros Thalassarche chlororhynchos sólo se reproduce en el archipiélago Tristan da Cunha y en la isla Gough en el Océano Atlántico Sur central, y se encuentra amenazado debido a la mortalidad causada por las pesqueras de espinel que operan en el Atlántico Sur. Se colectaron datos demográficos durante 20 años en dos colonias reproductivas en el archipiélago Tristan da Cunha y en la isla Gough. La variación anual en el número de aves reproductivas se correlacionó fuertemente entre las dos islas, y durante todo el período de estudio ambas poblaciones han presentado tendencias de decrecimiento de aproximadamente un 1.2% por año. El número de reproductores establecidos en la isla Gough ha disminuido significativamente y más rápidamente, a una tasa anual de 2.3%. El monitoreo de los reproductores que se establecen puede ser un medio sensible para detectar tendencias poblacionales. El éxito reproductivo promedio (67–69%) y la frecuencia de cría (66–65%) fueron muy similares en ambas islas. En la isla Gough la sobrevivencia aparente de inmaduros y adultos fue en promedio de 88 ± 3% y 92 ± 1%, respectivamente. La sobrevivencia de volantones a la edad de 5 años fue en promedio de 31 ± 8%. La sobrevivencia aparente de adultos en Tristan de Cunha fue en promedio sólo de 84 ± 2%. La sobrevivencia anual de las aves de Tristan se correlacionó negativamente con el esfuerzo de la pesca de espinel en el Océano Atlántico Sur. Los modelos poblacionales predicen tasas de disminución anuales de un 1.5–2.8% en la isla Gough y de un 5.5% en Tristan da Cunha. Comparaciones con congéneres sugieren que las disminuciones observadas y predichas son muy probablemente causadas por la baja sobreviviencia de adultos e inmaduros. La categoría de conservación del albatros T. chlororhynchos debería ser cambiada de “casi amenazada” a “en peligro.”


Oryx ◽  
1991 ◽  
Vol 25 (2) ◽  
pp. 76-79 ◽  
Author(s):  
Peter G. Ryan ◽  
John Cooper

The oriental driftnet fleet, which is responsible for the large-scale mortality of non-target species in the Pacific Ocean, has extended its range to include the South Atlantic Ocean. Relatively little is known about the areas of operation and impacts of driftnetting in the South Atlantic as yet, but it is emerging that driftnetting is equally devastating to the fauna of this ocean. This paper reviews the impact of the driftnet fishery on non-target species in the central South Atlantic Ocean. Several lines of evidence suggest that fishing effort is focused on Tristan da Cunha, apparently resulting in considerable mortality of rockhopper penguins Eudyptes chrysocome and other marine organisms. Britain should take steps to curb this destructive fishing technique in Tristan waters.


Polar Biology ◽  
2020 ◽  
Author(s):  
Alexander L. Bond ◽  
Christopher Taylor ◽  
David Kinchin-Smith ◽  
Derren Fox ◽  
Emma Witcutt ◽  
...  

AbstractAlbatrosses and other seabirds are generally highly philopatric, returning to natal colonies when they achieve breeding age. This is not universal, however, and cases of extraordinary vagrancy are rare. The Tristan Albatross (Diomedea dabbenena) breeds on Gough Island in the South Atlantic Ocean, with a small population on Inaccessible Island, Tristan da Cunha, ca 380 km away. In 2015, we observed an adult male albatross in Gonydale, Gough Island, which had been ringed on Ile de la Possession, Crozet Islands in 2009 when it was assumed to be an immature Wandering Albatross (D. exulans). We sequenced 1109 bp of the cytochrome b mitochondrial gene from this bird, and confirmed it to be a Tristan Albatross, meaning its presence on Crozet 6 years previous, and nearly 5000 km away, was a case of prospecting behaviour in a heterospecific colony. Given the challenges in identifying immature Diomedea albatrosses, such dispersal events may be more common than thought previously.


2021 ◽  
Vol 260 ◽  
pp. 112435
Author(s):  
Daniel Ford ◽  
Gavin H. Tilstone ◽  
Jamie D. Shutler ◽  
Vassilis Kitidis ◽  
Polina Lobanova ◽  
...  

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