Occurrence and structure of epipharyngeal pouches in bears (Ursidae)

The infrequent mention of epipharyngeal pouches occurring in some species o f bears indicates the scarcity of morphological and functional knowledge ab out these structures. In order to provide precise morphological data on the structure of these remarkable formations and to verify their taxonomic uti lity, the pharyngeal regions of 1 spectacled bear and 3 brown bears were ex amined. All these individuals possessed epipharyngeal pouches, which are tu bular, blind-ending outpouchings of the caudodorsal pharyngeal wall equippe d with respiratory epithelium and a thick layer of elastic fibres. While th e spectacled bear and Ursus arctos syriacus possessed a single pouch on the caudodorsal wall of the nasopharynx, in Ursus arctos and Ursus arctos beri ngianus 2 unequally sized pouches were present. Two additional sacs of smal ler size, representing outpouchings of the lateral pharyngeal wall, occurre d in the spectacled bear. These findings prove epipharyngeal pouches to be constant and unique morphological features of the family Ursidae, the anato mical features suggesting involvement in the respiratory system most probab ly in important aspects of ursid phonation. This is the first description o f epipharyngeal pouches in the spectacled bear.