Unpaired Ultimobranchial Glands of the African Lungfish, Protopterus dolloi

The ultimobranchial glands of juvenile African lungfish (Protopterus dolloi) (14 individuals; total body length 25-205 mm) were immunohistochemically examined. In individuals larger than 36 mm, one ultimobranchial gland was close to the left afferent branchial arteries. The topography of the ultimobranchial gland was similar to that of salamanders and sharks, but not to teleosts. With body growth, the ultimobranchial gland was vascularized and the parenchymal cells were gradually immunostained with anti-calcitonin antibody. In all individuals examined, the ultimobranchial gland existed only on the left side of the pharynx. These observations are discussed from a phylogenetic viewpoint.