The Eyes of an African Penguin (Spheniscus demersus): General Morphology and Ophthalmopathology

Author(s):  
Ekaterina Sokolenko ◽  
Gero Hilken ◽  
Nora Denk ◽  
Fabia Wyss ◽  
Christian Wenker ◽  
...  
ACS Omega ◽  
2020 ◽  
Vol 5 (51) ◽  
pp. 33280-33289
Author(s):  
Anddre Osmar Valdivia ◽  
Kristen Jasmin Ortega ◽  
Sanjoy K. Bhattacharya ◽  
Carolyn Cray

2016 ◽  
Vol 51 (2) ◽  
pp. 83-90 ◽  
Author(s):  
Christiaan Labuschagne ◽  
Lisa Nupen ◽  
Antoinette Kotzé ◽  
J Paul Grobler ◽  
Desiré L Dalton

Parasitology ◽  
2019 ◽  
Vol 146 (6) ◽  
pp. 791-804 ◽  
Author(s):  
Marcela P. A. Espinaze ◽  
Cang Hui ◽  
Lauren Waller ◽  
Francois Dreyer ◽  
Sonja Matthee

AbstractThe African penguin (Spheniscus demersus) is a critically endangered species endemic to southern Africa. Limited information is available on the parasite diversity associated with the species in natural settings. This study explores the diversity and incidence of parasites associated with African penguins and their nests, and records the effect of host and environmental factors on parasite infestation. Ecto-, haemo- and helminth parasites were recorded from 210 adult birds, 583 chicks and 628 nests across five colonies (two mainland and three islands) along the south-western coast of South Africa, in 2016 and 2017. Mean nest density (total and active nests) and climate variables (temperature and precipitation) were obtained for each colony. Parapsyllus humboldti was the most abundant and prevalent ectoparasite on penguins and in nests (69.10 and 57.80%, respectively), while Piroplasmorida/Haemospororida (33.51%) and Cardiocephaloides spp. (56.17%) were the most prevalent haemo- and helminth parasites of penguins, respectively. In general parasite abundance and prevalence was significantly affected by penguin age (chicks vs adults), location (mainland vs islands), nest density (total and active nests) and season (spring vs autumn/winter). It is concluded that parasite infestations are structured and that penguin chicks at mainland colonies are more susceptible to parasite infestations during spring.


2020 ◽  
Vol 50 (4) ◽  
pp. 917
Author(s):  
Matthew Golembeski ◽  
Samantha J. Sander ◽  
Jennifer Kottyan ◽  
William E. Sander ◽  
Ellen Bronson

2007 ◽  
Vol 55 (5) ◽  
pp. 317 ◽  
Author(s):  
Daniel B. Thomas ◽  
R. Ewan Fordyce

Penguins are generally smaller than the predicted minimum body size for marine endotherms. Anatomical observations of the little blue penguin (Eudyptula minor) suggest that extant penguins actively defeat the lower size threshold using regional heterothermy. The wing arteries in the little blue penguin form a humeral plexus, a series of three parallel arteries (including the marginal artery) that stem from the axillary artery, replacing a single brachial artery. Each artery of the plexus is associated with at least two veins to form a counter current heat-retention system. The humeral plexus thus restricts heat from entering distal areas of the wing and dissipating into seawater, ultimately reducing the bulk mass required for heat production and insulation. Humeral plexi are confirmed as a synapomorphic character of the Spheniscinae, with the humeral plexus of E. minor most similar to that of the African penguin Spheniscus demersus. The humeral plexus represents a loophole in body size minima of marine endotherms and offers insight into the ecology of living penguins.


2012 ◽  
Vol 4 (4) ◽  
pp. 1067-1069 ◽  
Author(s):  
Christiaan Labuschagne ◽  
Desiré L. Dalton ◽  
Antoinette Kotzé

2015 ◽  
Vol 11 (7) ◽  
pp. 20150237 ◽  
Author(s):  
Richard B. Sherley ◽  
Henning Winker ◽  
Res Altwegg ◽  
Carl D. van der Lingen ◽  
Stephen C. Votier ◽  
...  

Marine no-take zones can have positive impacts for target species and are increasingly important management tools. However, whether they indirectly benefit higher order predators remains unclear. The endangered African penguin ( Spheniscus demersus ) depends on commercially exploited forage fish. We examined how chick survival responded to an experimental 3-year fishery closure around Robben Island, South Africa, controlling for variation in prey biomass and fishery catches. Chick survival increased by 18% when the closure was initiated, which alone led to a predicted 27% higher population compared with continued fishing. However, the modelled population continued to decline, probably because of high adult mortality linked to poor prey availability over larger spatial scales. Our results illustrate that small no-take zones can have bottom-up benefits for highly mobile marine predators, but are only one component of holistic, ecosystem-based management regimes.


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