Selected ocular dimensions of three penguin species

Confocal and Electron Microscopic Structure of the Cornea from Three Species of Penguin

“…We are unsure as to why the posterior corneal lamellae were particularly thick in the gentoo and why there were less connections between lamellae in the central cornea of both king and gentoo penguins than in the little penguin [ 4 ]. The posterior cornea of both gentoo and king penguins has also been noted to become more swollen post mortem than the anterior half post-mortem, something not seen in the little penguin [ 3 ], and perhaps this difference in cross-connections between lamellae may account for that. However, we do note that both gentoo and king penguins have larger and flatter corneas than little penguins.…”

“…Demographic data is presented in Table 1 , including the corneal curvature where known, obtained using either the IOLMaster 700 (Carl Zeiss Meditech Inc., Jena, Germany), Nidek OPD-Scan III (Nidek Co. Ltd., Aichi, Japan) or Pentacam AXL (OCULUS Optikgeräte GmbH, Wetzlar, Germany). The latter data was included in a previous report [ 3 ]. All raw data is available in the online open access repository (Digital Science, London, UK).…”

“…The microstructure of the penguin cornea is of great interest because of its amphibious habit, and it has been postulated that its remarkably flat contour is an adaptation to its need to operate in both marine and terrestrial environments [ 1 , 2 ]. However, the shape of the penguin cornea does vary, with the smaller penguins having smaller, more steeply curved corneas [ 3 ]. The most recent transmission (TEM) and scanning (SEM) electron microscopic study of the penguin cornea was performed on what was described as a little penguin Eudyptula minor [ 4 ], although we note that these specimens were obtained in Western Australia while ours came from Auckland, New Zealand and recent evidence suggests that they are different species although of the same genus [ 5 , 6 , 7 , 8 , 9 ].…”

“…The aim of this study was to use confocal microscopy to examine the microstructure of the cornea of three species of penguin, the king Aptenodytes patagonicus , gentoo Pygoscelis papua and little penguins. We undertook this study on three different species partly because these three were those most readily accessible in Auckland but, given their vastly different foraging behaviours, known differences in corneal shape and the long period of independent evolution of each species [ 3 , 9 , 15 , 16 , 17 , 18 , 19 , 20 ], we also wished to look for variation within Spheniscidae, and for a possible correlation with size or diving depth. Because TEM of two of these species, namely the king and gentoo, has not previously been published, following confocal microscopy we undertook that examination on one cornea of each to look for any morphological differences between the three species, bar the obvious one of size [ 4 , 10 , 12 ].…”

An Overview of the Penguin Visual System

“…We identified articles relating to penguin head anatomy and vision by internet searches using the keywords: penguin, vision and eye on Google Scholar and the University of Auckland Library catalogue (which includes most major databases), from the reference list of a book on avian sensory ecology [ 2 ] (pp. 259–296), and from the references used by the current authors’ previously published works relating to penguins [ 34 , 35 , 36 , 37 ]. There are few articles that specifically relate to the penguin visual system itself.…”