The kidney of Leptonychotes weddelli (Pinnipedia: Phocidae) with some observations on the kidneys of two other southern phocid seals

• Published in: Journal of Morphology
• Main Authors: Vardy, P. H., Bryden, M. M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1981
• Subjects: Crabeater Seal; Elephant Seal; Leptonychotes weddelli; Lobodon carcinophagus; Mirounga leonina
• Online Access: http://dx.doi.org/10.1002/jmor.1051670103; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjmor.1051670103; https://onlinelibrary.wiley.com/doi/pdf/10.1002/jmor.1051670103

Abstract The structure of the kidney of Leptonychotes weddelli was examined using corrosion casts, India ink injection, and histological methods. Some observations were made on the kidney of the crabeater seal (Lobodon carcinophagus) and the elephant seal (Mirounga leonina) . The kidneys in all three species are reniculate, as in many other marine mammalian species. Features that have not been described previously in a phocid seal are a peripyramidal muscle, and venous drainage characterized by a large extrinsic system and a small intrinsic system. Examination of specialized fornices, relative medullary thickness, and the volumes of juxtamedullary relative to peripheral glomeruli (all of which relate to urine concentrating ability) revealed that each reniculus of Leptonychotes is similar to the unilobar kidney of a small mammal that produces only moderately concentrated urine. The high glomerular volume to cortical volume ratio may be related to high glomerular filtration rates after feeding observed in marine mammals. It is concluded that reniculation is more likely to be related to the large size of most marine mammals than to some factor related directly to the marine environment.