Encapsulated sensory corpuscles in the sclerocorneal boundary tissues of the killer whale &lt;i&gt;Orcinus orca&lt;/i&gt; L.

Vrabec, F

doi:10.1159/000143740

Cited by 10 publications

(12 citation statements)

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“…Despite the fact that these nerve endings' function remains uncertain ( Vrabec ; Wickham ; Dubielzig and Agiurre ; Hatfield et al . ), it is suggested that they act as receptors to maintain the intraocular pressure stability under water (Vrabec ; Wickham ; Hatfield et al . ).…”

Section: Discussionmentioning

confidence: 99%

Morphology of accessory structures of the humpback whale (Megaptera novaeangliae) eye

et al. 2014

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Rodrigues, F.M., Silva, F.M.O., Trompieri-Silveira, A.C., Vergara-Parente, J.E., Miglino, M.A. and Guimarães, J.P. 2015. Morphology of accessory structures of the humpback whale (Megaptera novaeangliae) eye. -Acta Zoologica (Stockholm) 96: 328-334.The humpback whale (Megaptera novaeangliae) has a cosmopolitan distribution and inhabits coastal and oceanic habitats, being present in polar and tropical waters. In aquatic mammals, vision has an important role in the perception of photoperiod changes. Due to lack of information on the morphology of Mysticetes, this study aimed to provide a morphological description of the adnexal structures of the humpback whale eye. Three newborn female specimens, stranded on the coast of Sergipe, Brazil, were used. Samples were fixed in a 10% formalin solution, dissected and photographed, and all the structures were collected and analysed using different light microscopy techniques. Eyelids were characterized by a palpebral fissure, a palpebral opening, two grooves (dorsal and ventral) and the presence of mechanoreceptors in the dermis. Some fibres of the four recti muscles had palpebral, scleral and glandular insertions. The Harderian gland filled the area between the orbit wall and the eyeball. Two vascular networks separated the extraocular retractor muscle of the eye and surround the optic nerve. The morphology of the accessory structures of the humpback whale eye was similar to that of other cetaceans, which suggests an adaptation to diving during migration, contributing to the perception of temperature difference in different regions.Juliana P. Guimarães, N ucleo de Estudo dos Efeitos Antropogênicos nos Recursos Marinhos/Fundac ßão Mam ıferos Aqu aticos, Av. Tancredo Neves,

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Section: Discussionmentioning

confidence: 99%

Morphology of accessory structures of the humpback whale (Megaptera novaeangliae) eye

et al. 2014

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“…Encapsulated sensory corpuscles (ESC) are specialized nerve endings of unknown function in the region of the iridocorneal angle of cetaceans (Fig ) . ESC are not found intraocularly in other mammals.…”

Section: Discussionmentioning

confidence: 99%

“…It has been suggested that ESC within the cetacean eye may function as pressure receptors, possibly to IOP . There are few IOP measurements in cetaceans.…”

Section: Discussionmentioning

confidence: 99%

Anatomic features of the cetacean globe

Miller

Samuelson

Dubielzig

2013

Veterinary Ophthalmology

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The horizontal diameter of the globe was longer than the vertical diameter. The posterior sclera was thick, causing the internal axial length (and therefore the optical axis) to be shorter than the vertical diameter. The cornea was composed of an epithelium, Bowman's layer, collagenous stroma, thin Descemet's membrane and endothelial layer. Bowman's layer was present in all specimens except one Kogia breviceps. The thickness was variable, with the acellular layer thickest in Tursiops truncatus and thinnest in Kogia sp. The iris was well vascularized and muscled while the ciliary body lacked musculature, but retained vasculature. Single and clustered ESC were found in the anterior uvea, sclera surrounding the anterior uvea, trabecular meshwork, or some combination of these locations. They were often regionally grouped and varied from 0 to 21. There were three species where no ESC were found, L. borealis, D. capensis, and S. bredanensis, but the presence of these corpuscles cannot be ruled as only one section of the globe was analyzed.

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“…Other cetaceans have been found to have well‐developed iris musculature, which may be a tool to help focus light underwater, in addition to the spherical lens. Many species of odontocete cetaceans studied thus far have been noted to have a unique type of encapsulated corpuscle located in various areas within the iridocorneal angle, which may function in regulation of aqueous humor dynamics in these animals lacking ciliary body musculature 5,17 , 18 …”

Section: Introductionmentioning

confidence: 99%

“…11 The pilot whale is lacking in ciliary body musculature like the West Indian manatee. 13 Other cetaceans such as the beluga whale ( Delphinapterus leucas ) and narwhal ( Monodon monoceros ) were also found to lack this structure, 11 as did the the killer whale ( Orcinus orca ) , 18 the humpback whale ( Megaptera novaeangliae [ boops ]), 5 and the nine species of odontocete cetaceans studied by Wickham. 17 The pilot whale, as mentioned earlier, does have increased ciliary body vasculature as in the West Indian manatee.…”

Section: Introductionmentioning

confidence: 99%

Structure and presumptive function of the iridocorneal angle of the West Indian manatee (Trichechus manatus), short‐finned pilot whale (Globicephala macrorhynchus), hippopotamus (Hippopotamus amphibius), and African elephant (Loxodonta africana)

Hatfield¹,

Samuelson²,

Lewis³

et al. 2003

Veterinary Ophthalmology

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The iridocorneal angles of prepared eyes from the West Indian manatee, short-finned pilot whale, hippopotamus and African elephant were examined and compared using light microscopy. The manatee and pilot whale demonstrated capacity for a large amount of aqueous outflow, probably as part of a system compensating for lack of ciliary musculature, and possibly also related to environmental changes associated with life at varying depths. The elephant angle displayed many characteristics of large herbivores, but was found to have relatively low capacity for aqueous outflow via both primary and secondary routes. The hippopotamus shared characteristics with both land- and water-dwelling mammals; uveoscleral aqueous outflow may be substantial as in the marine mammals, but the angular aqueous plexus was less extensive and a robust pectinate ligament was present. The angles varied greatly in size and composition among the four species, and most structures were found to be uniquely suited to the habitat of each animal.

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Encapsulated sensory corpuscles in the sclerocorneal boundary tissues of the killer whale <i>Orcinus orca</i> L.

Cited by 10 publications

References 1 publication

Morphology of accessory structures of the humpback whale (Megaptera novaeangliae) eye

Morphology of accessory structures of the humpback whale (Megaptera novaeangliae) eye

Anatomic features of the cetacean globe

Structure and presumptive function of the iridocorneal angle of the West Indian manatee (Trichechus manatus), short‐finned pilot whale (Globicephala macrorhynchus), hippopotamus (Hippopotamus amphibius), and African elephant (Loxodonta africana)

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